Animal Kingdom

Animal Kingdom
INTRODUCTION
There is a vast diversity in the number and types
of animals in nature. They range from unicellular
to multicellular. They are found in the deepest
of the oceans, in snow-covered mountains, from
the poles to the equator. There are differences in
the structure and forms of the different animals.
But there are some fundamental features in them
which show resemblance such as arrangement
of cells, body plan, symmetry, segmentation,
coelom, germ layer, body temperature, skeleton
and notochord, types of digestive, respiratory,
circulatory, excretory, reproductive systems.
We need to classify organisms to make our study
easier and to study the interrelationship between
different groups.
BASES OF CLASSIFICATION
Habitat
y On the basis of habitat, animals are divided into
the following types:
⚪ Aquatic-Organisms that are found in water.
They can be:
Marine-Echinoderms, many sponges and
coelenterates.
Animal Kingdom – Characteristics of Classification

Fresh water-Prawns, some fishes and
molluscs.
⚪ Terrestrial-Organisms that are found on land.
They can be:
Fossorial animals (found in burrows) -
Earthworm, snake, rabbit.
Arboreal (found on trees) - Birds, bats,
monkeys.
Scansorial (climb the walls) - House
lizards, squirrels.
Gray Matter Alert!!!
Marine phyla: Phylum Echinodermata,

Ctenophora and phylum Hemichordata are
three exclusively marine phyla.
1.
Levels of Organisation
y Animals are divided into five types, on the basis
of their level of organisation:
⚪ Protoplasmic level of organisation: A cellular
body performs all the biological activities.
Example: Protozoa
⚪ Cellular level of organisation: The cells of
the body are present in loose aggregates and
together perform all the functions.
Example: Sponges
⚪ Tissue level of organisation: The cells of the
organism unite together to form a tissue
system which helps the organism to perform
different functions.
Example: Coelenterata
⚪ Organ level of organisation: The tissues
combine together to form organs which
perform different functions.
Example: Platyhelminthes
⚪ Organ system level of organisation: The
organs of an organism combine together to
form different organ systems which help in
the functioning of the whole organism.
Examples: Aschelminthes to Chordata.
Symmetry
It is the arrangement of the body organs on either
side of the main axis of the body. It is of two
types – Asymmetry and symmetry.
y Asymmetry: When the body of an organism
cannot be divided into two identical halves in any
plane.
Examples: In some sponges and snails.
y Symmetry: When the body of an organism can be
divided into two identical halves in one or more
planes. On the basis of the plane involved, it is of
two types:
⚪ Radial:
When the body of an organism can be
divided into two identical halves by any
2.
plane passing through the central axis of
the body.
For sessile animals, radial symmetry was
useful as it helped them in food gathering
from all sides. They might have developed
appendages all around to capture the prey.
Examples: Coelenterates, Ctenophores,
Echinoderms
⚪ Bilateral:
When the body of an organism can be
divided into two identical halves by only
one plane, passing through the longitudinal
axis of the body.
It arose when animals on the ocean floor
became mobile. A crawling animal will
encounter food with the end that moves
first.
So, mouth developed at this end. Sensory
organs and a coordinating brain developed
at the front end.
These organs helped in sensing food. So,
the head enclosing the brain became
associated with the mouth end. This is
cephalization.
Examples: Annelids, Arthropods.
3.
Body Plan
Animals show three different types of body plan:
y Cell aggregate plan: In this case, the body is just
an aggregate of cells.
Example: Sponges
y Blind sac plan: In this case, the multicellular

organism has tissue or organ level of organisation.
The organism has only one opening for intake of
food as well as it is through this pore, the waste
is thrown out of the body.
y Tube within the tube plan: In this case, the body
consists of two tubes. One tube is formed by
the wall of the body and the second is formed
by the digestive tract. It has two openings. One
at the anterior for intake of food and the other
at the posterior end for egestion of undigested
food. It is of two types – Protostomes and
Deuterostomes.
4.
⚪ Protostomes: ‘Proto’ means first and ‘stoma’
means mouth. Thus, in protostome organisms, Definition
the development of the mouth in the embryo
takes place first followed by the anus. Cephalization: Differentiation of
Examples: Flatworm, roundworm, Annelida, head at the anterior end during
Mollusca embryonic development.
⚪ Deuterostomes: ‘Deutero’ means second, and
‘stoma’ means mouth. Thus, in deuterostome
organisms, the development of the anus takes
place first and development of mouth in the Definitions
embryo takes place after it.
Examples: Echinodermata, Hemichordata, Protostomes: Organisms in
Chordata which the mouth is developed
first in the embryo, followed by
Germ Layers the anus.
The layer of the gastrula which gives rise to the Examples: Planaria, Ascaris,
different parts of the body is called the germ earthworm, Pila, wasp
layers. On the basis of the number of the layers,
there are two categories: Deuterostomes: Organisms in
y Diploblastic: Two germ layers i.e., ectoderm and which the anus develops first
endoderm give rise to the different parts of the in the embryo, followed by the
body. In between the two layers is present a non- mouth.
cellular layer known as mesoglea. Examples: Starfish,
Examples: Sponges, Coelenterate, Ctenophora Balanoglossus, rohu, snake,
pigeon, deer
5.
y Triploblastic: Three germ layers i.e., ectoderm,
mesoderm and endoderm give rise to the Previous Year’s Question
different parts of the body. Examples: Flatworm
to mammals
Which one of the following kinds
of animals are triploblastic?
(1) Flatworms
(2) Sponges
(3) Ctenophores
(4) Corals
Segmentation
Segmentation is the division of a body into
portions known as segments. It is of four types:
y Metameric segments (True segmentation): The

body is divided into segments; internally and
externally.
Example: Annelida
y External Segmentation- Arthropoda
y Internal Segmentation- Chordata
y Pseudometamerism (False segmentation):
The segments of the body are not formed
from the embryo and thus are known as
pseudometamerism.
Example: Tape worm
6.
Coelom
The space between the body wall and the gut wall
is known as coelom. On the basis of the nature
of coelom, organisms are of the following types:
y Acoelomates: Organisms do not have any cavity
or coelom and thus are called as acoelomates.
Examples: Platyhelminthes, porifera,
coelenterate, ctenophora
y Pseudocoelomates: The mesoderm is present in

form of small pouches between the ectoderm
and endoderm.
Example: Aschelminthes
7.
Definition
Pseudocoelomate: In these
organisms, mesoderm is present
in form of small pouches
in between the two layers
ectoderm and endoderm.
y Coelomates (Eucoelomates): It is a body cavity

which arises from the mesoderm. It is of three
types:
⚪ Schizocoelom: It develops due to the split in
the mesoderm sheet.
Examples: Arthropods, molluscs, annelids
⚪ Enterocoelom: The mesoderm arises from
the wall of the embryonic gut as a hollow
outgrowth and forms the coelom.
Examples: Echinoderms, chordates
⚪ Haemocoelomates: In Arthropods and
Molluscs, the true coelom is reduced and
filled with blood and known as haemocoel.
8.
Skeleton
The framework of the body that gives shape and
protection to the animals is known as skeleton.
It is of two types on the basis of their position:
y Endoskeleton: Hard structure that is present
inside the body.
Examples: Bones present inside the body, like
humans.
y Exoskeleton: It is present outside the body. It is

of different types like-
⚪ Calcareous shells in Mollusca.
⚪ Epidermal scales in reptiles.
⚪ Feathers in birds.
⚪ Hair, nails, claws, horns in mammals.
Notochord
It is a solid, unjointed and mesodermal rod,
present on the dorsal side of the body. Depending
upon its presence or absence, there are two
groups of animals:
y Non-Chordates: Organisms that do not have the
notochord are known as non-chordates.
Examples: Poriferans to Hemichordates
9.
y Chordates: Organisms that have the notochord
are known as chordates. Definition
Examples: Pisces to mammals
Notochord: A solid, unjointed
Cleavage mesodermal rod present on
It is of two types: the dorsal side of the body. In
y Mosaic (Determinate) Cleavage: Complete some animals, it develops into a
embryo is formed from the whole blastomere. If vertebral column in later stages
any of the blastomere gets detached accidentally of their life.
then the embryo formation will cease.
Example: Annelids
y Non-Mosaic (Non-determinate) Cleavage: On
separation of some of the blastomeres in the
early stage, the leftover blastomeres will give Keywords
rise to the complete embryo.
Example: Chordates
Diploblastic
Triploblastic
Development
Coelomate
y Indirect: The young one does not resemble the
Pseudocoelomate
parent. It undergoes metamorphosis through a
Protostomes
number of larval or nymphal stages to develop
Deuterostomes
into an adult.
Examples: Mosquito, frog, tape worm
10.
y Direct: The young one resembles the adult and it
does not undergo metamorphosis. Definition
Examples: Humans, birds
Metamorphosis: Drastic
changes through which the larva
of an organism, structurally and
morphologically modifies into
the adult.
Examples: Development of
butterfly and frog
Types of Eggs
Based on the quantity of yolk, they are of three
types:
y Microlecithal: The amount of yolk in the egg is
less.
Examples: Eggs of Herdmania, Sea Urchin
y Mesolecithal: The amount of yolk in the egg is
moderate.
Examples: Eggs of frog, fish, toad
y Macrolecithal: The amount of yolk in the egg is

high.
Examples: Eggs of birds, reptiles, bony fishes.
Based on the distribution of yolk in the cytoplasm

of egg, they are of three types:
⚪ Homolecithal: Yolk is uniformly distributed.
Examples: Eggs of Annelids, molluscs,
protochordates
⚪ Telolecithal: Yolk is concentrated in the
vegetal half.
Examples: Eggs of Amphibians
⚪ Meiolecithal: Yolk is present in the entire
ooplasm, except for a little disc-shaped space
in the cytoplasm for the nucleus.
Examples: Eggs of Reptiles
11.
⚪ Centrolecithal: Yolk is present in the centre
of the cell.
Examples: Eggs of insects
Body Temperature
On the basis of body temperature, organisms are
of two types:
y Homeotherms (Warm-blooded animals): The

body temperature does not change with the
change in ambient temperature.
Examples: Birds, mammals. Previous Year’s Question
y Poikilotherms (Cold-blooded animals): The body
temperature changes with the change in the Temperature changes in the
ambient temperature. environment affect most of the
Examples: Amphibians, pisces, reptiles animals which are
(1) poikilothermic
Digestion (2) homeothermic
Based on where the digestion takes place, it is (3) aquatic
divided into two types: (4) desert living
y Intracellular: Digestion takes place within the
cells of the body.
Examples: Amoeba
12.
y Extracellular: Digestion takes place outside the
cell, in a cavity of an organ.
Examples: Hydra
Digestive System
It is of two types:
y Incomplete: A single opening that functions both
as a mouth and anus.
y Complete: Two openings, i.e. mouth and anus are
present. Definitions
Examples: Arthropoda, annelida, aschelminthes,
chordata Aerobic Respiration: Respiration
that occurs in the presence of
Respiration Oxygen. High amount of energy
Organisms follow two modes of respiration: is generated.
y Aerobic respiration: Organisms respire in the
presence of oxygen. Anaerobic Respiration:
Examples: Mammals, reptiles, coelenterates Respiration that occurs in the
y Anaerobic respiration: Organisms respire in the absence of oxygen. Less amount
absence of oxygen. of energy is generated.
Example: Flatworms
Table. Different modes of respiration in animals

Modes of Respiration Respiratory Organs Animals
• Body surface Body surface Sponge, sea anemone
• Branchial Gills Garden snail, rohu
• Cutaneous Skin Earthworm, frog
• Tracheal Trachea Cockroach
• Booklung Booklungs Spider, scorpion
13.
Modes of Respiration Respiratory Organs Animals
• Buccopharyngeal Buccopharyngeal cavity Frog, toad
Toad, snake, crocodile,

• Pulmonary Lungs
pigeon, deer
Circulation
It is of two types:
y Open circulation: In such a circulation, the blood
flows through a space called sinuses. The sinuses
are known as Haemocoel.
y There is no capillary system.
y The blood flows at low pressure.
y Body tissues and important organs exchange
respiratory gases, nutrients and waste products
directly from blood.
Examples: Arthropoda, Mollusca.
y Closed circulation: In such a circulation, the

blood flows through the blood vessels.
y The blood flows at high or low pressure.
Examples: Annelids, mammals.
Excretion
The process by which the nitrogenous waste is
thrown out of the body is known as excretion.
It is of following types, on the basis of the main
nitrogenous waste:
14.
y Ammonotelism: When the main nitrogenous
waste is ammonia. Such animals are known as Previous Year’s Question
ammonotelic.
Examples: Sponges, coelenterates, ctenophores,
Which of the following does not
echinoderms
have an open circulatory system?
y Ureotelism: When the main nitrogenous waste is
(1) Frog’s tadpole
urea. Such animals are known as ureotelic.
(2) Prawn
Examples: Amphibians, mammals
(3) Chelifer
y Uricotelism: When the main nitrogenous waste is
(4) Cockroach
uric acid. Such animals are known as uricotelic.
Examples: Birds, reptiles, insects.
Dual Excretion: Some animals

have dual mode of excretion.
Examples: In normal condition,
earthworm secretes urea but
it secretes ammonia when
sufficient water is available.
Excretory Organs Animals

• Body surface Sponges, sea anemone, starfish
• Protonephridia (flame cells) Flatworms
• Intracellular tubes Roundworms
• Nephridia Earthworm
• Antennary/green glands Prawn
15.
Excretory Organs Animals
• Malpighian tubules Cockroach
• Coxal gland Scorpion and spider
• Kidneys Garden snails, alligator
Nervous System
y System that helps the organism to coordinate all Previous Year’s Question
of its function. Different organisms have different
types of nervous system.
Uricotelism is found in
y Sponges do not have any nerve cell.
(1) mammals and birds
y Coelenterates have diffused type of nervous
(2) fish and fresh water
system.
protozoans
y Flatworms and roundworms have a ladder-type
(3) birds, land reptiles and
nervous system.
insects
y Echinoderms have two ring nervous system.
(4) frogs and toads
Reproduction
The process by which an adult organism gives
rise to a young one of its own kind is known as

reproduction. It is of two types:
y Asexual reproduction: In this type of reproduction, Definitions
only a single parent is involved. Gametes are not
formed. Asexual Reproduction: The
Examples: Hydra, Penicillium process by which a single parent
y Sexual reproduction: In this type of reproduction, gives rise to a new individual.
two parents are involved. Gametes are formed Examples: Amoeba, Hydra
and fertilization and meiosis take place.
y Organisms can be unisexual (as in humans) or Sexual Reproduction: The
bisexual (as in earthworm) where both the sexes process by which the gametes
are present in the same organism. of two parents fuse to give rise
y Fertilization can be internal (as in mammals) or to an offspring.
external (as in fishes and amphibians).
16.
CLASSIFICATION IN ANIMALS
y On basis of the above-given characteristics, animals were classified into
different groups by the different scientists.
y Aristotle: He divided animalia into two groups:
y Anaima: It included animals without red blood cells.
Examples: Sponges, Arthropoda, Mollusca.
y Enaima: It included animals with red blood cells.
Example: Chordates
Many scientists later tried to classify organisms into different groups but
the finally accepted classification is of Robert Whittaker.
17.
y Robert Whittaker’s five kingdom classification
(1969): Whittaker divided the living organisms
into five kingdoms:
⚪ Monera
⚪ Protista
⚪ Fungi
⚪ Plantae
⚪ Animalia.
In 1969, Robert Harding Whittaker proposed this
system. He argued that fungi, which had been
previously placed along with plants, had a unique
method of obtaining food. So he proposed
Kingdom Fungi and separated it from plants. Now,
living organisms are divided into five kingdoms; Keywords
Monera, Protista, fungi, Plantae and Animalia.
Cell structure
Criteria used by Whittaker for his classification Body organisation
scheme was: Mode of nutrition
y Cell structure Reproduction
y Body organisation Phylogenetic relationship
y Mode of nutrition
y Reproduction
y Phylogenetic relationships
This system placed all prokaryotes in Kingdom

Monera and unicellular eukaryotes were placed

in the kingdom Protista. Fungi were elevated to
the level of kingdom.
y Animalia is divided into 31 phyla, 11 of which are Previous Year’s Question
considered to be major ones.
y Animal kingdoms have organisms which are
Five kingdom system of
multicellular, eukaryotic, heterotrophic. They
classification suggested by R.H.
lack a cell wall.
Whittaker is not based on
y They depend upon plants or plant products for
(1) presence or absence of a
their food.
well defined nucleus
y They digest food inside a cavity.
(2) mode of reproduction
y They store digested food as Glycogen and fats.
(3) mode of nutrition
y They respond to stimuli and have a nervous
(4) complexity of body
system. Exception-Sponges do not have nerve
organisation
cells.
18.
Summary: Classification of Animal Kingdom
Broad classification of kingdom Animalia based on common fundamental characters.
19.
Summary: Characteristics of Animal Kingdom
20.
Summary: Characteristics of Classification
21.
Non-Chordata
Phylum Protozoa
y Initially, it was placed in animal kingdom but they could not be called as
animals as they showed characteristics of both plants and animals like
Euglena. Thus finally Haeckel placed them in a separate kingdom Protista
and later Robert Whittaker maintained its status as a kingdom in his
five kingdom classification. But here we will keep in mind the traditional
concept and study it here as a phylum of Non-Chordata.
y Microscopic one-celled organism performs all the metabolic activities, and
thus known as ‘Acellular’ organisms.
y Habitat:
⚪ Aquatic
⚪ Terrestrial,
⚪ Free living -Amoeba
⚪ Parasitic -Plasmodium
⚪ Solitary or colonial -Proterospongia
⚪ Pathogenic causes diseases-Entamoeba histolytica, Leishmania
y Level of body organisation: Protoplasmic level.
y Consists of protoplasm with a single or more than one nucleus.
y Maybe enveloped by plasmalemma, pellicle, cyst, theca, lorica or shell.
y Locomotion: By means of-
⚪ Pseudopodia-Amoeba
⚪ Flagella-Euglena
⚪ Hairy cilia-Paramoecium
⚪ No locomotory organelles-Plasmodium
y Nutrition
⚪ Holozoic-Amoeba
⚪ Mixotrophic-Euglena
⚪ Parasitic- Plasmodium
⚪ Digestion is intracellular, takes place in food vacuole.
y Respiration: By exchange of gases through body surface
y Excretion: Takes place by contractile vacuole.
⚪ Nitrogenous waste is Ammonia.
⚪ Some fresh water protozoans get rid of excess water through contractile
vacuole and the phenomenon is known as Osmoregulation.
⚪ Amoeba has one vacuole and Paramoecium has two vacuoles.
Non-Chordata
22.
Paramoecium-It is
heterokaryotic i.e possesses
two nuclei, macronucleus and
micronucleus.
Macronucleus is polyploid and
is the somatic nucleus that
controls the metabolic activities.
Micronucleus is diploid and
controls the reproductive
activities of the organism.
y Reproduction:
⚪ Asexual
Binary fission -Amoeba
Definition
Transverse fission -Paramoecium
Longitudinal fission - Euglena
Binary fission-A mode of
Multiple fission -Plasmodium
asexual reproduction in which a
unicellular parent cell divides to
form two daughter cells.
Non-Chordata
23.
⚪ Sexual :
Syngamy -Plasmodium
Conjugation -Paramoecium
y Some also form cyst which helps in reproduction
in unfavorable conditions. They do not have
natural death because in unicellular animals,
growth is always followed by binary fission.
The parent cell divides and forms two daughter
individuals and thus, loses its identity.
y Examples:
⚪ Amoeba Rack your Brain
⚪ Plasmodium
⚪ Euglena Which organisms are considered
⚪ Leishmania to be immortal?
Classification of Protozoa
Phylum Protozoa is classified into the following
four classes on the basis of modes of locomotion-
y Mastigophora or Flagellata: Locomotion is by
flagella.
Examples: Trypanosoma gambiense, Giardia
intestinalis
y Sarcodina: Locomotion by pseudopodia.
Examples: Amoeba, Entamoeba histolytica
y Ciliata: Locomotion by cilia.
Example: Paramoecium
y Sporozoa: Locomotory organs absent.
Example: Plasmodium
Non-Chordata
24.
PHYLUM PORIFERA (Sponges or pore bearing)
y Robert Grant gave the term ‘Porifera’. They are
commonly known as Sponges.
y Shape: tubular, vase-like, cylindrical and
branched.
y Habitat: Aquatic, mostly marine and a few are
found in fresh water (Spongilla). They are solitary
or colonial. They are attached to the substratum
and hence are sessile.
y Level of body organisation: They are multicellular,
having a cellular level of organisation.
y Symmetry: Mostly asymmetrical.
y Germ Layer: They are diploblastic, having two
layers namely dermal layer and gastral layer.
y Body layers: The body wall of sponges consists
of three layers Pinacoderm, Choanoderm and
Mesenchyme lining the central cavity called the
spongocoel.
⚪ Pinacoderm:
The layer present externally is known as
epidermis or pinacoderm. It is a single
layer of cells which are polygonal in shape,
known as pinacocytes.
Pinacocytes have nucleus in the center.
The cells show contractility, which helps
the sponges to increase and decrease in
size.
This layer also contains tubular cells
known as pore cells or porocytes. They
are the modification of pinacocytes.
The space present in the porocytes is
known as ostia or incurrent pore. Each
porocyte allows water to move to the
spongocoel.
⚪ Choanoderm:
The layer lines the spongocoel is the
gastrodermis or choanoderm. It consists
of flagellated collar cells, known as Connecting link: Proterospongia
choanocytes. is a connecting link between
Non-Chordata
The choanocyte consists of ovoid cell with Protozoa and Porifera.

a transparent collar which surrounds the
flagella.
25.
The flagella beat and ensure the flow of
water within the body of the animal. Definition
⚪ Mesenchyme:
The non-cellular layer present between Choanocytes- Flagellated
the Pinacoderm and Choanoderm is cells which have a collar of
mesenchyme.It consists of gelatinous protoplasm at the base of the
matrix known as mesoglea. flagellum. They line the canal
The matrix contains many amoeba-shaped chambers of sponges.
cells called amoebocytes and minute
skeletal elements made up of calcium
known as spicules.
Amoebocytes are modified into many
different types namely-
• Archaeocytes give rise to totipotent
cells.
• Trophocytes (nurse cells) provide
nutrition to the cells.
• Thesocytes store food.
• Chromocytes contain the coloured
pigments which provide colour to the
sponges.
• Scleroblasts secrete spicules. The
calcareous spicules are present
between the Pinacoderm and
Choanoderm and form the skeleton of Keywords
the sponges. They can be made up of
calcium or silicon Calcoblasts are the Spongocoel
calcareous spicules. Choanocyte
• Gland cells are the cells that secrete Hermaphrodite
slimy substance. Ascon, Sycon, Leucon
• Germ cells are the cells that form the Cell structure
sperms and ova.
y Coelom: Acoelomate
y Canal System: A distinguishing feature of the
sponges is the presence of a canal system in the
body.
This system helps the organism to obtain food and
oxygen from the surrounding medium whereas
harmful substances and reproductive bodies are
Non-Chordata
carried out of the body. There are three types of

canal system-
26.
y Ascon: It is the simplest type of canal system,
found in asconoid sponges like Leucosolenia.
The body consists of minute pores called as
incurrent pores which leads to the single large
cavity known as spongocoel. Spongocoel opens
into the outside by a circular opening known as
osculum.
Ingressing water 

Through dermal ostia
→ Spongocoel

Through Osculum
→ To the outside
⚪ Sycon: It is a complex type of canal system

found in syconoid like Sycon, Grantia. It is
formed by the folding of the wall of asconoid
sponges. It includes two types of canals i.e.,
incurrent and radial, which alternate with each
other. Both the canals are interconnected
with a pore (known as prosopyle) between
them. Water moves into spongocoel through
the apopyles and then moves out by
osculum.

→ Incurrent
Non-Chordata
canals 
Prosopyles
→ Radial canals 
Apopyles
→
Spongocoel 
Through Osculum
→ To the outside
27.
⚪ Leucon: The walls of the leuconoid sponges
show further folding, that leads to the
complex leucon type of canal system. The
incurrent canal enters into the flagellated
chambers through the prosopyles, which
lead into the excurrent canal through the
apopyles. Excurrent canal is developed due
to the shrinkage of the spongocoel.

→ Incurrent
canal 
Prosopyles
→ Flagellated chambers →
Apopyles → Excurrent canal → →Through Osculum
To the outside
y Nutrition: Digestion is intracellular, and food

consists of microscopic plants and animals.
y Respiration: Takes place by diffusion through the
water that moves into the canals.
y Excretion: Occurs through the canals.
y Reproduction: They reproduce asexually as well
as sexually.
⚪ Asexually, they reproduce by buds or by the Definition
gemmule formation.
⚪ They are hermaphrodite and sperm and ovum
Indirect development : The
are formed. The sperms are released into
young one does not resemble
water, which move into another sponge and
the parent. It undergoes
fuses with the ovum to form a zygote.
metamorphosis through a
⚪ Development is indirect and takes place by
number of larval or nymph
the formation of a ciliated larva known as
stages to develop into an adult.
amphiblastula.
y Examples:
⚪ Euspongia: Bath sponge
⚪ Euplectella: Venus flower basket
⚪ Spongilla: Fresh Water sponge
Classification of Phylum Porifera:

y Phylum Porifera is classified into the following
three classes on the basis of the types of
Non-Chordata
Spicules-
28.
⚪ Class Calcarea or Calcispongiae: Exoskeleton
is formed of calcareous spines. Examples-
Leucosolenia, Scypha
⚪ Class Hyalospongiae or Hexactinellida:
Exoskeleton is formed of six-rayed siliceous
spicules. Examples- Euplectella, Hyalonema
⚪ Class Demospongiae-Exoskeleton is either
formed of spongin fibres or siliceous spicules
or both. Examples- Euspongia, Spongilla
y Distinctive Features Over Protozoa

⚪ Multicellular
⚪ Presence of canal system
⚪ Formation of gametes
⚪ Development of larva
PHYLUM COELENTERATA OR CNIDARIA

y The term ‘Coelenterata’ was given by Leuckart
while Hyman gave the term ‘Cnidaria’.
y Habitat: They are aquatic and most of them are
found in marine water except Hydra which is a
freshwater cnidarian.
y They are solitary or colonial and may be sedentary
or free swimming.
y Level of organisation: They are the first group of
organisms that show tissue level of organisation.
y Symmetry: They show radial symmetry.
y Germ Layer: They are diploblastic animals.
y The body wall: The outer Epidermis and inner
Gastrodermis. In between these two layers, a
non-cellular layer called mesoglea is present.
y Epidermis: It is the outer-most layer and consists
of small cuboidal cells. Its function is protective
and sensory. Various cells that constitute this
layer are:
⚪ Epithelio-muscle cells: The muscle contracts
and shortens the body and the tentacles.
⚪ Gland cells: Secrete a sticky material which
Hydra has power of regeneration.
helps in capture and entanglement of the
Non-Chordata
It was discovered by Trembley.

prey.
29.
⚪ Interstitial cells: Ability of regeneration Thus, mechanical and chemical
and hence also known as totipotent stimulation is necessary for the
or reserve cells. These cells help in discharge of the nematocyst.
regeneration, budding and formation of Once the nematocyst comes
other cells like the reproductive cells, out, it cannot be used again. The
glandular, stinging cells. cnidoblast of the nematocyst
⚪ Sensory cells: Found specially on the moves to the gastrovascular
tentacles, hypostome and pedal disc. cavity and is digested.
⚪ Nerve cells/Ganglia: They are present Discharged nematocysts are
in the coelenterates (first one to have formed within 48 hours.
nerve cells). They are found in the ⚪ Gastrodermis: Inner layer of the
epidermis layer and formed from the body lining the gastrovascular cavity.
interstitial cells. It consists of the following cell:
⚪ Germ cells: The interstitial cells in ⚪ Endothelio-muscular or nutritive
summer, differentiate and give rise to cells: The cells consist of two
the gonads which differentiate into flagella, which keep the liquid food
testes or ovaries. inside the body cavity in moving
⚪ Cnidoblasts: Many of the interstitial state.
cells of the epidermis become ⚪ Endothelio-gland cells: Enzymatic
specialized to form the stinging cells gland cells secrete digestive
called cnidoblasts. When they are enzymes into the cavity for digestion.
developed, they migrate to the tentacles Mucous glands secrete lubricants
through the mesoglea by the amoeboid and paralyse the prey.
movement. ⚪ Interstitial cells: They are totipotent
Cnidoblasts are oval in shape and and can transform into any other
consist of the nematocyst (stinging types of cells when required.
organ). ⚪ Sensory cells: They are stimulated
They act as an organ of defence. It is by the presence of a prey into the
filled with a poisonous fluid known body.
as hypnotoxin, which consists of ⚪ Nerve cells: Similar to those that
proteins and phenols. appear in the epidermis. Nematocysts
The cnidoblast projects out of the are absent in the gastrodermis.
epidermis as a tiny hair like structure ⚪ Mesoglea: A non cellular, thin layer
known as the cnidocil. present between the epidermis and
Discharge of nematocyst takes place gastrodermis.
when the cnidocil is stimulated by
the touch of the food and the prey.
Non-Chordata
30.
y Nutrition: They are carnivorous and feed on
nematodes, insects and crustaceans.
⚪ The prey is captured by the nematocysts and
partially extracellular digestion takes place
(outside the cell in a cavity).
⚪ Then it is moved into the gastrovascular
cavity and intracellular digestion takes place.
Digested food is sent to all parts of body.
y Respiration: It is carried out by the body surface
via diffusion.
Non-Chordata
y Excretion: Ammonia is the chief excretory

product.
31.
y Nervous System: A primitive form of nervous shaped and formed by blastostyle.
system is present, which consists of a ⚪ Medusa has four gonads. Reproduces
network of nerve cells and their processes. sexually.
y Reproduction: Life cycle of a coelenterate ⚪ Metagenesis is seen in Obelia. In
consists of two forms- it, the polyp reproduces asexually
⚪ One is the attached polyp and the other to form medusa and medusa
is the free-swimming medusa. reproduces sexually to form polyp.
⚪ Polyps are fixed and cylindrical in shape. Such an alternation of generation is
Polyps are without gonads. Polyps feed known as metagenesis.
and protect the colony and reproduce ⚪ Direct or indirect development takes
asexually by budding. place by planula, scyphistoma and
⚪ Medusa is free living. It is umbrella- ephyra.
Non-Chordata
32.
y Examples:
⚪ Hydra: Fresh water polyp
⚪ Obelia: Sea fur
⚪ Physalia: Portuguese man-of-war
⚪ Adamsia: Sea anemone
⚪ Pennatula: Sea-pen
⚪ Meandrina: Brain coral
Classification of Phylum Cnidaria

y Phylum Cnidaria is classified into the following
three classes on the basis of the dominance of
medusa or polyp phase in the life cycle-
y Class Hydrozoa: Water animals. They have either
polyps or both polyps and medusa are present.
Examples – Obelia, Physalia
y Class Scyphozoa: Cup-shaped animals. They have
medusa only. Examples – Aurelia, Rhizostoma
y Class Anthozoa: Flower-shaped animals. They
have polyps only. Examples – Adamsia, Meandrina
Distinctive features over Porifera

y Tissue level of organisation
y Digestive cavity is present
y Tentacles with cnidoblast
y Few nerve cells are present
y Motile forms are also present
Non-Chordata
33.
PHYLUM CTENOPHORA
y The phylum is commonly known as comb jellies
or sea walnuts. Ktene means comb-a group of
cilia and phoros means bearing. Initially,they
were placed as a subphylum in Cnidaria but
Eschscholtz recognised it as a separate phylum
Cnetophora. Nematocysts are absent so known
as Acnidaria.
y Habitat: Mostly marine, solitary, free swimming
y Level of organisation: Tissue level of organisation.
y Symmetry: Symmetry is radial. The arrangement
of combs gives it a radial symmetry whereas
the tentacles and the gastrovascular cavity are
bilaterally symmetrical.
y Germ layer: They are diploblastic, having outer
epidermis and inner gastrodermis.
y Coelom: Acoelomate
y Body structure: Most adult, tentacle-bearing
ctenophores have a high capacity to regenerate
the missing body regions.
⚪ The body wall consists of two layers – the
epidermis and gastrodermis and middle jelly-
like mesoglea with some cells and muscle
fibres.
⚪ Nematocysts are absent. Special adhesive
cells known as Colloblasts are present in
the epidermis of the tentacles which help in
capture of food.
y Locomotion: It is with the help of eight external
vertical ciliated comb plates called as swimming
plates. The combs usually propel away from the
mouth and thus they usually swim in the direction
in which the animal is eating. Bioluminescence: Ctenophores
y Nutrition: The digestive tract consists of the or comb jellies use
mouth, pharynx, stomodeum or stomach, which bioluminescence for instant
is highly coiled, has canals and two anal pores. signalling. Calcium changes
⚪ Thus, digestive tract is complete. Digestion is the shape of the enzyme
both extracellular and intracellular. photoprotein and it produces
⚪ They are carnivorous animals. Most of the light.
Non-Chordata
unwanted matter is thrown out of the mouth
34.
and small unwanted particles are ejected
through the anus.
y Nervous System: The brain and central nervous
system are absent in them. Nervous system is
diffused type.
y Respiratory, circulatory and excretory systems
are absent.
y Reproduction: They are hermaphrodite, except
the members of genus Ocyropsis, which are
dioecious.
⚪ Asexual reproduction is absent. They
reproduce sexually.
⚪ The gamete formed, moves out of the body
from the mouth. Fertilization is thus external.
⚪ In Coeloplana and Tjalfiella, gametes are
taken in through the mouth and fertilization
is internal.
⚪ Development includes Cydippid larvae. When
there is shortage of food, they become small
in size and do not produce gametes. Once
the food supply becomes normal, they grow
in size and reproduce.
y Most ctenophores are capable of reproduction
before they reach adulthood and this is known
as paedogenesis.
y Examples:
⚪ Pleurobrachia: Sea Gooseberry
⚪ Beroe
⚪ Cestum: Venus’s Girdle
Classification of Ctenophora
y Phylum Ctenophora is classified into the following
two classes, on the basis of the presence or Corals: They are hard materials
absence of tentacles: secreted by marine, mostly
y Class Tentaculata: Two, long, aboral tentacles colonial, polypoid coelenterates.
are present. Examples – Cestum, Coeloplana Corals form the stable marine
y Class Nuda: Tentacle is absent. Example – Beroe ecosystem.
Corallium rubrum is a type of red
coral which is used in jewellery
Non-Chordata
as red moonga stone.
35.
Distinctive Features Over Cnidaria
Comb like ciliary plates
Bioluminescence
Keywords
PHYLUM PLATYHELMINTHES (FLAT WORMS)
y The term Platyhelminthes was given by Gegenbaur.
Platy-flat;helminth-worms. Metagenesis
y Habitat: They are mostly parasitic and a few are Cnidoblasts
free-living like Dugesia. Bioluminescence
y Level of Organisation: They have an organ level Colloblasts
of organisation. The body is dorsoventrally flat
and hence known as flatworms. The body is
usually unsegmented like in Liver fluke (Fasciola
hepatica) except in Tapeworm (Taenia solium).
y Symmetry: They have bilateral symmetry (first

Rack your Brain
bilateral animal).
y Germ Layer: They are first triploblastic organisms.
y Body structure: The space between the body wall Which proglottides of tapeworm
Non-Chordata
is filled with parenchyma. The fluid present in show apolysis and why?
36.
the parenchymal walls maintains the body shape
and acts as a hydroskeleton.
⚪ Muscles in the body wall are mesodermal.
⚪ Below the epidermis longitudinal, circular,
oblique muscles are present.
⚪ The body consists of sucker with which they
attach to the host. The suckers are present at
the anterior end i.e. oral suckers.
⚪ First animal to have cephalisation.
y Coelom: Acoelomate. Gray Matter Alert!!!
y Nutrition: Digestive system consists of an
alimentary canal which is incomplete (without Parasitic adaptations in
anus). Platyhelminthes:
⚪ Mouth leads into the pharynx, then Flattened body for easy
oesophagus which opens into the intestine attachment to the host.
and the intestine is divided into many Suckers and hooks to attach
branches known as diverticula or caeca. This to the organs of the host.
is the case in Liver fluke. In tapeworm the gut Produce a large number of
is absent. eggs or sperms.
y Respiration: Well-developed respiratory system. Outer layer resistant to the
⚪ Respiration is through the body surface. digestive enzymes of the host.
⚪ Parasites like Taenia show anaerobic
respiration.
y Excretion: Excretory system consists of flame
cells or protonephridia that consist of cilia. Definitions
⚪ The cilia move and this appears like flickering
flame and is thus known as flame cell. Flame Independent host: A host in
cells are also known as Solenocytes. which the parasite undergoes
⚪ Flame cells help in osmoregulation. its asexual phase.
⚪ Excretory pore present on the ventral surface Example: Snail is an intermediate
of the body. host of liver fluke.
Primary host: A host in which a
parasite attains sexual maturity.
Example: Sheep is a primary
host of liver fluke.
Non-Chordata
37.
y Nervous system: Nervous system consists of a
brain around the pharynx.
⚪ Nervous system is primitive and ladder-like
having a brain ring and 1-3 paired longitudinal
nerves connected at intervals by transverse
commissures.
⚪ Nerves arise from the brain towards the
anterior and posterior part of the body.
y Reproduction: They are hermaphrodite.
⚪ Life cycle is digenetic i.e., completed in two
hosts.
⚪ Primary host is sheep and secondary host is
snail as in Liver fluke. Primary host is man and
secondary host is pig in case of Tapeworm.
⚪ Self-fertilization is seen in Taenia and cross-
fertilization is seen in Fasciola.
⚪ Development is through the formation of many
larval forms. In flukes miracidium, sporocyst,
redia, cercaria and metacercaria larvae are
Non-Chordata
present. In tapeworm, oncosphere, hexacanth

and cysticercus larvae are seen.
38.
⚪ Skeletal system and circulatory system are
absent.
⚪ Regeneration: It takes place in some of the
flat worms like in Planaria.
y Examples:
⚪ Dugesia: Planaria
⚪ Schistosoma: Blood fluke
⚪ Fasciola: Liver fluke
⚪ Taenia: Tapeworm
Table. Common Flatworm Infections in Human
Disease Causative Agent Organ Affected
Fascioliasis Fasciola hepatica Liver
Taeniasis, Cysticercosis Taenia solium Intestine
Schistosomiasis Schistostoma japonicum Blood
Echinococcus
Echinococcosis Liver, lungs
multilocularis
Fasciolopsiasis Fasciolopsis buski Intestine
Classification of Phylum Platyhelminthes

Is classified into the following three classes on
the basis of body shape, mouth position and
habitat:
y Class Turbellaria: Body is leaf-like, free-living
and mouth is present on the ventral side. Highest
power of regeneration. Examples – Planaria
y Class Trematoda: Body is leaf-like, either ecto or
Non-Chordata
endoparasites. Mouth is present on the anterior

end. Example – Fasciola
39.
y Class Cestoda: Ribbon-like, endoparasites.
Mouth and alimentary canal are absent. Example:
Taenia solium
Distinctive Features Over Ctenophora

y Organ level of organisation Previous Year’s Question
y Bilateral symmetry
y Triploblastic
Which one of the following is a
y Nervous system with brain, nerve cords
matching set of a phylum and its
y Organised excretory organs, gonads
three examples?
(1) Porifera-Spongilla,
PHYLUM ASCHELMINTHES OR
Euplectella, Pennatula
NEMATHELMINTHES OR NEMATODA
(2) Cnidaria - Bonellia, Physalia,
(ROUNDWORM)
Aurelia
y Gegenberg proposed the term – Nemathelminthes.
(3) Platyhelminthes -Planaria,
y The word “nematode” comes from a Greek word
Schistosoma, Enterobius
‘nema’ that means thread ‘eidos’ means form.
(4) Mollusca -Loligo, Teredo,
They are commonly known as roundworms, as
Octopus
they appear round in cross-section. They are
found in aquatic and terrestrial habitat. Some are
parasitic and are some free living.
y Level of organisation: The body is unsegmented,
elongated, cylindrical, tapering towards the two
ends. They have organ level of organisation.
y Germ layer: Triploblastic
y Body Structure: Body wall consists of an outer
cuticle, middle syncytial epidermis and innermost
longitudinal muscles.
⚪ Cuticle is thick, tough, transparent layer
secreted by the epidermis. It consists of five
distinct layers.
⚪ First layer is made up of lipids, second layer is
made up of keratin, third layer is sulphur-rich
protein matricin, and fourth layer is of fibres,
and the fifth layer is the inner basement
membrane.
⚪ Cuticle secretes anti enzymes which
neutralizes the effect of the digestive juices
of the host.
Non-Chordata
40.
⚪ Epidermis is present below the cuticle, bearing
fat and glycogen reserves. The innermost
layer consists of longitudinal muscles.
⚪ The pressure of the fluid and action of the
surrounding muscles are used to change an
organism’s shape that produces movement. Rack your Brain
y Coelom: True coelom is absent. Pseudocoelom as
mesoderm is found in the form of small pouches There is an absence of circulatory
in between the ectoderm and endoderm. system in Ascaris. How does
⚪ The pseudocoelomic cavity is filled with the it transport food, oxygen and
pseudocoelomic fluid. It maintains the shape waste in its body?
of the body and forms the hydro skeleton of
the body.
y Digestion: The digestive tract is complete and
straight.
⚪ It consists of the mouth, muscular pharynx,
straight intestine and anus. Previous Year’s Question
⚪ They feed on the blood and the partially or
fully digested food from the host. Food is Ascaris is characterized by
sucked by the rhythmic muscular activity of (1) presence of true coelom but
the pharynx. absence of metamerism
⚪ Digested food is absorbed by the intestine (2) presence of true coelom and
and the undigested food moves out of the metamerism (metamerisation)
anus. (3) absence of true coelom but
Respiration: Respiration occurs through the presence of metamerism
surface of the skin. (4) presence of neither true
y Excretion: Excretory system is simple. coelom nor metamerism.
⚪ Flame cells or protonephridia are absent.
They consist of giant cells known as renette
cells or H-shaped excretory system.
⚪ It consists of two longitudinal excretory
canals which are connected by a transverse
network (below the pharynx). This transverse
duct opens into a common canal that runs to
the excretory pore.
y Nervous system: Consists of nerve ring or
circumpharyngeal ring that forms nerves forward
and backward in the body.
⚪ Sensory organs are present and they are
Non-Chordata
of three types namely Papillae, Amphids,
41.
Phasmids.
⚪ Papillae are present on the lips, surrounding
the mouth.
⚪ Cervical papillae are present behind the lips
and they are tactile in function. Anal papillae
are present ventrally, below the posterior end
in males and help in copulation.
⚪ Near a single papilla, a single amphid is present.
These are gustatory or chemoreceptors.
Phasmids are chemoreceptors opening on
either side of the tail.
y Reproduction: Sexes are separate and hence
show sexual dimorphism.
⚪ The female body is longer than the male body.
Fertilization is internal. Development may be
direct or indirect. Indirect development takes
place by the formation of larva.
⚪ Filariform larva is found in Ancylostoma
(Hookworm), Microfilaria larva is found in
Wuchereria (filarial worm), Rhabditiform larva
is present in Ascaris.
⚪ Well-developed respiratory, circulatory and
skeletal system is absent.
y Examples:
⚪ Ascaris: Intestinal Roundworm
⚪ Wuchereria: Filarial worm
⚪ Ancylostoma: Hook worm
Non-Chordata
42.
Table. Common Worm Infections in Human
Disease Causative Agent Organ Affected
Ancylostomiasis Ancylostoma duodenale Intestine
Ascariasis Ascaris lumbricoides Intestine
Enterobiasis Enterobius vermicularis Intestine
Small intestine,
Trichinosis Trichinella spiralis
periorbital region
Lymphatic Filariasis Wuchereria bancrofti Lymphatic system
Classification of Platyhelminthes
It is classified into the following two classes, on
the basis of the presence or absence of phasmids:
y Class Aphasmidia: Phasmids are absent, while
Amphids are present. Examples – Plectus,
Epsilonema
y Class Phasmidia: Phasmids are present. Examples
– Rhabdias, Enterobius
Distinctive Features Over Platyhelminthes

y Syncytial Epidermis
y Muscular layer of body wall
y Digestive tract is complete
PHYLUM ANNELIDA (SEGMENTED WORM)

y The phylum Annelida was named by Lamarck.
y Habitat: They occur in fresh water, seawater or
moist soil. Some are free-living and some are
Non-Chordata
burrowing or parasitic. The body of the Annelids

is divided into metameric segments (externally by
43.
ring like growth known as annuli and internally
by transverse septa).
y Level of Organisation: They show organ-system
level of body organisation.
y Symmetry: Bilateral symmetry.
Body Segmentation: Peristomium is the first

segment of the body that differs from the other
segments. It surrounds the ventrally elongated,
slit-like mouth (peri-around; stoma-mouth)
hence named as peristomium.
⚪ Prostomium is not a true segment, it is a
triangular fleshy lobe lying in front of the
mouth.
⚪ It consists of two pairs of eyes and a pair of
short cylindrical sensory tentacles and two-
jointed palps.
Body layers: The body wall consists of cuticle,
epidermis and muscles.
⚪ The epidermis consists of columnar cells
which consist of glandular and sensory cells.
The epidermis secretes cuticle.
Non-Chordata
⚪ Cuticle prevents desiccation of the body

and provides protection. The glandular cells
44.
secrete mucus which lines the burrow in
which they live and prevents them from
collapsing.
Muscles lie below the epidermis. Circular,
longitudinal and oblique muscles are present.
⚪ The pressure of the fluid and action of the
surrounding muscles are used to change an
organism’s shape and produce movement.
y Germ layer: Triploblastic
y Ceolom: They are coelomate. The coelom is Previous Year’s Question
schizocoelic in nature i.e. developed by the
splitting of the embryonic mesoderm.
Which one of the following is
⚪ Many septa divide the cavity into
not a characteristic of Phylum
compartments.
Annelida?
y Locomotion: is brought about by the setae,
(1) Pseudocoelom
parapodia and suckers.
(2) Ventral nerve cord
⚪ Setae are stiff bristles present on the body.
(3) Closed circulatory system
Parapodia are flattened, fleshy flap-like
(4) Segmentation
outgrowth of the trunk which is present on
the lateral side of the body.
⚪ Parapodia near the middle part of the trunk
are the largest which goes on decreasing in
size towards the two ends.
⚪ Suckers are present in Leeches and help in
locomotion.
y Nutrition: They are carnivorous (Nereis), omnivores
(Earthworm), and sanguivorous (feeding on blood)
like Leech.
Rack your Brain
⚪ Digestive tract is complete with the presence
of mouth, buccal cavity, pharynx, oesophagus,
True coelom and closed
stomach, intestine, rectum and anus.
circulatory system were first
⚪ Mouth lies ventrally, a post-oral ciliated band
evolved in which group of
lies behind the mouth.
organisms during the course of
⚪ Gut has the presence of oesophagus, stomach,
evolution?
and intestine.
Respiration: It takes place with the help of the
moist skin (known as cutaneous respiration) and
by parapodia. In some organisms, respiration also
takes place through the gills.
Non-Chordata
y Circulation: It is of closed type.
45.
⚪ It means that the blood flows through closed
tubes or blood vessels. Blood consists of
plasma containing many nucleated, colourless,
amoeboid cells or corpuscles and dissolved
pigment haemoglobin or erythrocruorin. Gray Matter Alert!!!
⚪ It gives red colour to the blood and helps in
transport of respiratory gases and food in the An anticoagulant hirudin is
body. present in salivary glands of blood
y Excretion system: It consists of numerous coiled sucking leeches (Sanguivorous).
structures placed in the metameric segments
known as nephridia.
⚪ They are present in all segments except a few
anterior and posterior ones. Each nephridium
consists of nephrostome, body and terminal
ducts.
⚪ Nephrostome consists of a ciliated
funnel communicating with the coelom.
Nephrostome leads into the short tube-like
neck. The body consists of two parts, a short
straight lobe and a twisted lobe.
⚪ Twisted lobe consists of proximal and distal
limb. The distal limb ends in a short, narrow
duct known as terminal duct. They excrete
ammonia out of the body.
y Nervous system: It consists of the central
nervous system, peripheral nervous system and
sympathetic nervous system.
⚪ Central nervous system comprises the nerve
ring and ventral nerve cord. The nerve ring
consists of a paired cerebral ganglia.
⚪ A pair of pear-shaped ganglia connect
together to form the brain, which lies between
the buccal cavity and pharynx in the third
segment.
⚪ The ventral nerve cord sends nerves to the
posterior end of the body. The peripheral
nervous system supplies nerves from the
ganglion to the other segments of the body.
⚪ Sympathetic nervous system forms a nerve
Non-Chordata
net beneath the epidermis, within the muscles
46.
of the body wall and alimentary canal.
⚪ Sensory receptors like tactile receptors,
gustatory receptors and photoreceptors are
found in the Annelids.
y Reproduction: Annelids are both unisexual (as in
Nereis), bisexual (as in Earthworm).
⚪ Fertilization is external.
⚪ Development is mostly direct. If indirect,
the fertilized eggs develop into trochophore
larvae.
⚪ Later, they sink to the sea-floor and
metamorphose into adults. Trochophore larva
is minute, ciliated, unsegmented and pear-
shaped.
⚪ In a well-grown larva, a tuft of cilia in the
apical sensory organ is present.
⚪ A very unique feature of the larva is the
presence of preoral ciliated girdle of cilia
(prototroch) cells above the equator.
⚪ Larval nephridia are present in the lower part
of the body.
y Examples:
⚪ Lumbricus
⚪ Pheretima -Earthworm
⚪ Hirudinaria -Bloodsucking leech
Classification of Phylum Annelida

y Phylum Annelida is classified into the following
four classes, on the basis of the presence or
absence of parapodia, setae, metamers:
⚪ Class Polychaeta – Segmentation is internal or
external. Setae many on the lateral parapodia.
Examples – Nereis, Aphrodita
⚪ Class Oligochaeta – Segmentation is internal
and external. Few Setae. Examples –
Lumbricus, Nais
⚪ Class 3 – Hirudinea-Segmentation is external
without internal septa. Setae absent. Example
– Leech
Non-Chordata
⚪ Class 4 – Archiannelida-Segmentation is
internal. No setae. Examples – Dinophilus,
47.
Protodrilus.
Distinctive Features Over Aschelminthes

y Metameric segmentation
y Presence of parapodia
y Closed circulatory system
PHYLUM ARTHROPODA (ANIMALS WITH JOINTED

APPENDAGES)
y Habitat: They are found in air, water, land,
burrowed in soil and in the bodies of plants and Gray Matter Alert!!!
animals. The body consists of jointed legs or
appendages.
Living fossil: Limulus has shown
y Level of Organisation: They have an organ-system
no changes since it has evolved
level of organisation
on the earth and therefore is
y Symmetry: Show bilateral symmetry and body is
known as living fossil.
segmented.
y Coelom: They are coelomate.
y Germ Layer: Triploblastic
y Body structure: Body is divided into head thorax
and abdomen.
⚪ The head and thorax fuse together to form the
cephalothorax. The body wall or exoskeleton
consists of a single layer of epidermis, an
internal basement membrane and cuticle.
⚪ The epidermis is one cell thick and gives
rise to the basement membrane. Cuticle is
secreted by the epidermis. It is present all
over the body except the midgut region.
⚪ Cuticle is divided into two layers-Epicuticle,
Procuticle. Epicuticle is made up of proteins,
lipids and a waxy layer. This waxy layer makes
the cuticle impermeable to water.
Rack your Brain
⚪ The procuticle is made up of chitin protein.
In some Arthropoda, there is a deposition of
calcium carbonate and calcium phosphate on Muscles developed for the first
it. Cuticle provides protection and rigidity to time in _________.
the insects.
⚪ Cuticle becomes thick, hard and non-flexible
Non-Chordata
which makes the predation of arthropods

difficult.
48.
y Nutrition: They have different types of ⚪ The alimentary canal consists of
mouthparts for feeding, biting and chewing stomodaeum (foregut), mesenteron
like that are found in the grasshoppers, (midgut) and proctodaeum (hindgut).
cockroaches; piercing and sucking type as From the mouth, the food reaches
present in mosquito and bed bug, chewing the stomach where food is acted
and lapping type found in honey bees, upon by the enzymes.
sponging type as in housefly and siphoning ⚪ The digested food is absorbed by
as in butterfly. Digestive system is complete the small intestine and undigested
with mouth and anus. food moves out of the anus.
Non-Chordata
49.
y Respiration: In arthropods occur through the body
surface, gills,book lungs or tracheae. Spiracles
are tiny breathing pores present on the sides of
the thorax and abdomen.
⚪ Air moves into the body through the spiracles.
Spiracles open into an opening known as
atrium which leads into fine air tubes known
as tracheae.
⚪ Tracheae are further branched to form
tracheoles which are filled with fluid tissue
that helps in exchange of gases by diffusion.
⚪ Book lungs consist of a series of leaflike plates
within a chamber. They are usually found in
the 3rd to 6th segment of the body.
⚪ Air is drawn in and expelled out of this
chamber by muscular contraction. Horseshoe
crabs have book gills which are analogous to
book lungs but function in arthropods found
in water.
y Circulation: The circulatory system in arthropods
is open; their blood flows through cavities
between the internal organs and not through
closed vessels.
⚪ Arthropods consist of a heart which is divided
into a linear row of chambers, one in each
segment of the body, which helps in pumping
blood to different parts of the body.
⚪ Blood or haemolymph consists of clear liquid
plasma and white blood cells. Blood has no
pigment.
y Excretion: It is through the malpighian tubules
or green glands. Malpighian tubules are slender
projections that emerge from the digestive tract
that are attached at the junction of the midgut
and hindgut.
y Nervous system: It is similar to that found in the
Annelids. Sensory organs like tentacles and eyes
are present.
Non-Chordata
50.
⚪ Eyes found in arthropods are compound eyes.
They are composed of many independent
visual units, often thousands of them, called
ommatidia.
⚪ Each ommatidium is covered with a lens and
linked to a complex of eight retinular cells
and a light-sensitive central core.
y Reproduction: They are dioecious. Fertilization is
internal. Development is direct or indirect with
some larval forms.
⚪ Parthenogenesis takes place in some Rack your Brain
arthropods. Development of an egg into a
complete individual without fertilization Eusocial phenomenon is seen in
is called parthenogenesis. This type of which organisms?
development is seen in the male honeybees.
y Examples:
⚪ Bombyx mori – Silk moth
⚪ Apis indica – Honey bee
⚪ Mantis – Praying mantis
⚪ Palamneus – Scorpion
⚪ Aranea – Spider
Classification of Phylum Arthropoda

y Phylum Arthropoda is divided into many subphyla
and classes on the basis of the body divisions
and presence or absence of appendages. Few
of the subphyla have been divided into classes.
Some of the classes are:
⚪ Class – Crustacea: The body is divided into
cephalothorax. and abdomen. Two pairs of
antennae and a pair of compound eye are
present. Example – Palaemon, Cancer
⚪ Class – Chilopoda: Body is divided into head
and trunk. Each trunk bears a pair of legs.
Example – Scolopendra (Centipede)
⚪ Class – Arachnida: The body is divided into
cephalothorax and abdomen. It bears six pairs
of appendages. Examples – Scorpion, Spider
⚪ Class – Diplopoda: Body is divided into
Non-Chordata
head, thorax and abdomen. A single pair of
51.
antennae is present. Each thoracic segment
bears a pair of legs. Example – Julus
⚪ Class – Insecta: Body is divided into head,
thorax and abdomen. Consists of a pair
of antennae and a pair of compound eye.
Examples – Silverfish, termites, Butterfly
⚪ Class – Merostomata: Example – Limulus
Distinctive Features Over Annelida

⚪ External segmentation only
⚪ Jointed appendages
⚪ Exoskeleton of Chitin
PHYLUM MOLLUSCA (SOFT BODIED ANIMAL)

y It is the second-largest phylum after Arthropoda.
Mollusca is derived from the word mollis or
molluscs which means soft-bodied.
y Habitat: It consists of all marine animals ranging
from a giant squid to a small snail.
y Level of Organisation: Organ-system level of
organisation.
y Symmetry: It is bilateral but in Pila (apple snail)
due to the presence of twisting of the body during
the growth (torsion) is asymmetrical.
Non-Chordata
52.
y Germ Layer: Triploblastic
y Coelom: coelomate, (Shizocoelom – greatly
reduced) unsegmented. Coelom is reduced. It is
present around the heart, kidney and gonads.
y Body Structure: Neopilina is a segmented mollusc.
The body is divided into head, mantle, muscular
foot and visceral hump.
⚪ The foot or podium is muscular and is distinct
from the rest of the body. In Pila, the foot
consists of many pedal glands which secrete
a slime trail during locomotion.
⚪ Head foot complex is attached to the visceral
mass by a short neck.
⚪ Foot gets its nerve supply from the pedal
nerve cords or pedal ganglia. Mantle is a
layer which encloses the cavity known as the
mantle or pallial cavity.
⚪ The animal retracts its head and foot into
the cavity in order to protect itself from any
danger and to rest.
⚪ The head is retracted first and then the body.
Mantle also secretes the shell in most of the
molluscs.
Non-Chordata
53.
y Nutrition: Some molluscs are herbivores
while others are carnivores. The digestion is
extracellular.
⚪ The Digestive tract is complete, starting
with the mouth and ends with the anus.
The mouth consists of radula which can be
compared to a tongue and consists of minute Rack your Brain
teeth present on them.
⚪ The radula helps the molluscs to take in food. Radula is one of the
It is used in feeding by snails, to bore through characteristics of Mollusca, but
shells by predator snail, to cut the prey by which Mollusc lacks a radula?
squids. The digestive tract is ciliated.
y Respiration: In molluscs, it can be cutaneous
or Pallial, Branchial or Ctenidial or Pulmonary
respiration. Respiration by the integument or by
the mantle is the simplest method. Gray Matter Alert!!!
⚪ Respiration occurs through the soft surface
of the body. Most of the aquatic molluscs Haemocyanin: It is present in
respire by the gills or by ctenidia. Water flows the blood of the Molluscs which
through it and by the process of diffusion gives it a blue colour when
gases are exchanged. exposed to oxygen.
⚪ In some molluscs, actual gills are absent and
other morphologically different structures
are present.
⚪ In Doris, anal gills are present; while in Aeolidia
adaptive gills are present on the dorsal surface
of the body. In terrestrial molluscs like Limax
gills or ctenidium are absent and the mantle
cavity is transformed into pulmonary sac or Pearl: It is formed by nacre layer.
lungs for aerial respiration. Nacre layer’ is called ‘Mother of
y Excretion: Excretory organs are a pair of pearl’. This layer is made up of
metanephridia. Ammonia is the main excretory CaCO3 and conchiolin protein.
substance.
y Circulation: The blood circulates between
gills and heart, through the blood-filled space
haemocoel.
y Except cephalopods, all molluscs have an open
circulatory system.
y Nervous system: It comprises of cerebral,
Non-Chordata
pleural, pedal and visceral ganglia connected by

connectives and commissures.
54.
⚪ Connectives connect dissimilar ganglion and
commissures connect similar ganglion. In
many molluscs, a short fleshy stalk known
as Ommatophore is present on either side
behind the second pair of tentacles.
⚪ At the tip of the ommatophores are present
a black, circular eye. Statocysts i.e., organ of
equilibrium is present in the molluscs.
⚪ Each statocyst is a hollow structure filled
with fluid and calcium particles known as
statoconia.
y Reproduction: They have separate sexes, but
several snails are hermaphrodites.
⚪ Sperm and eggs are spawned into the water.
⚪ Fertilization is external, but internal
fertilization can also be seen in several
species.
⚪ Development is indirect through the free larval
forms Veliger, Trochophore or Glochidium.
y Examples:
⚪ Neopilina
⚪ Chaetopleura: Chiton
⚪ Unio: Fresh water mussel
⚪ Pila: Apple snail Connecting link: Neopilina is
⚪ Loligo: Squid a connecting link between
⚪ Octopus: Devil fish Annelida and Mollusca.
Classification of Phylum Mollusca

y Phylum mollusc is divided into seven classes on
the basis of the shell:
⚪ Aplacophora: Shell absent. Example –
Neomenia
⚪ Monoplacophora: They are one plate bearing.
The shell is spoon-shaped. Example –
Neopilina
⚪ Polyplacophora/Amphineura: Shell consists
of 8 plates. Non-ganglionated nerve ring
is present around the mouth with two
interconnected nerve cords. Example – Chiton
Non-Chordata
⚪ Scaphopoda: Shell is tubular and open at

both ends. Example – Dentalium
55.
⚪ Gastropoda: It includes the largest number
of molluscs. Shell is made up of one piece.
Example – Helix
⚪ Pelecypoda or Bivalvia: Shell is made up of
two halves. Pinctada, Unio
⚪ Cephalopoda: Shell is external, Head and foot
region are modified to form a structure which
has eyes and tentacles. Thus, their name
is cephalopoda or ‘head –foot’. Examples –
Sepia, Loligo, Octopus
y Distinctive features over Arthropoda
⚪ Distinct head
⚪ Better sense organs
⚪ Gills/lungs for respiration
PHYLUM ECHINODERMATA (SPINY SKINNED

ANIMALS)
y Initially, Echinodermata was placed along with
colelenterata in Radiata. Later, Leukart in 1847,
identified it as a separate group. Echinodermata
(echinos-spiny; derma-skin) are known as spiny-
skinned animals. The term echinodermata was
coined by Jacob Kleen.
y Habitat: They are marine animals and found at
the bottom of the water body. Except-Synapta
similis, some are free living or sessile.
⚪ The shape of the body may be star-shaped,
cylindrical or spherical.
⚪ The star-shaped body consists of five
radiating arms ambulacral and five interradii
arms called as inter-ambulacral.
y Level of organisation: They have an organ-system
level of organisation of the body,
y Coelom: Coelomate.Coelom is lined by amoeboid
cells.
y Germ layer: Triploblastic and the body wall
consists of epidermis which extends all over the
body. It consists of scattered gland cells and
neurosensory cells.
Non-Chordata
⚪ The gland cells secrete a protective mucus

sheet around the body. The neurosensory
56.
cells are connected to form a nerve net below
the epidermis.
⚪ Below the epidermis, lies the dermis which
consists of the self-secreted calcareous
plates or ossicles.
⚪ Pedicellariae are a small wrench- or claw-
shaped appendage with movable jaws, called
valves which are present on the body of some
echinoderm like sea star and sea urchin.
⚪ They keep the body surface clear of algae,
encrusting organism, and other debris.
y Symmetry: The larval forms show bilateral
symmetry. The five-armed adults show radial
symmetry. The echinoderms have the ability of
regeneration and autotomy.
y Canal System: The echinoderms consist of canal
system which is a modification of the coelom.
⚪ It consists of a calcareous perforated plate on
the aboral surface of the central disc known
as madreporite.
⚪ This madreporite leads to the stone canal
which is known as madreporic canal.
⚪ Stone canal opens into the ring canal, which
is in the form of a pentagonal ring around the
oesophagus.
⚪ There are small, rounded yellowish structures
that open into the ring canal on the inner side.
⚪ Such bodies are known as Tiedemann’s
glands. The ring canal gives out radial canals
which further give out two series of lateral
canals.
⚪ The lateral canal opens into the tube feet.
Each tube foot consists of rounded sac-like
structure called as ampulla, a middle tubular
part podium and a cup-like sucker at the
lower end.
Non-Chordata
57.
y Circulation: A true blood vascular system is
absent in the echinoderms. It consists of a haemal
system which is enclosed within a perihaemal
system.
y Respiration: It occurs through the structures
known as dermal branchiae or papullae which
are outgrowths on the surface of star fish. They
are continuous with the coelom and help in
exchange of gases by diffusion. Respiration also
occurs through peristominal gills in sea urchins,
genital bursae in brittle star.
y Nervous system: It is primitive. It consists of
nerve net consisting of nerve fibres and some
ganglion cells. They are present in the whole
body. Neurosensory cells are present on the
epidermis. They are of two types – tactile and
olfactory. Tactile cells are found in the tube feet
and olfactory cells are present around the mouth.
Sea star possess red eyespots at the end of each
arm at the base of the terminal tentacle.
y Excretion: Well developed excretory system is
absent. Ammonia is the excretory product which
is thrown out of the body through the papullae.
Non-Chordata
y Reproduction: Sexes are separate except in few

individuals. Fertilization is external. Development
58.
is indirect through the free swimming larval
forms. The larval forms are the early Bipinnaria,
later Bipinnaria, Brachiolaria, Holothuroidea,
Echinoidea larva.
y Examples:
⚪ Asterias–Star fish Gray Matter Alert!!!
⚪ Ophiura–Brittle star
⚪ Echinus–Sea urchin Antedon: It shows high power of
⚪ Cucumaria–Sea cucumber autonomy and regeneration.
⚪ Antedon–Sea lily
Classification of Phylum Echinodermata

y Phylum Echinodermata is divided into five classes
on the basis of the shape of the body:
⚪ Class Asteroidea: Body is star-shaped.
Example – Asterias
⚪ Class Ophiuroidea: Body is star-like, sharply
marked off from the central disc.
Example – Ophiothrix
⚪ Class Echinoidea: Body is globular or disc-
like. Example – Echinus (sea urchin)
⚪ Class Holothuroidea: Body elongated and
cylindrical.
Example – Holothuria (sea cucumber)
⚪ Class Crinoidea: Body has a central disc.
Example – Antedon
y Distinctive Features Over Mollusca
⚪ Water vascular system for locomotion
⚪ Radial symmetry
PHYLUM HEMICHORDATA
y hemi-half; chorde-chord. Initially was treated as
a sub-phylum of Chordata but later given the
status of an independent phylum.
y Habitat: They are living in burrows and are mostly
marine.
y Shape: Body is elongated worm like consisting of
proboscis, collar and trunk.
y Body layer: Skin layer consists of single epidermis.
Non-Chordata
y Symmetry: Bilateral
59.
y Coelom: Body cavity is enterocoelus, that is
divided into protocoel, mesocoel and metacoel.
y Germ Layers: Triploblastic
y Nutrition: Mostly ciliary feeders. Complete
alimentary canal is present in digestive system.
⚪ This is straight or U-shaped. Digestive tract is
complete.
⚪ Narrow openings called gill slits are present
on the dorsal side. They are usually present in
several pairs.
y Respiration: Occurs through the gill slits. Ciliary
filter feeders present that test the quality of
water and food entering the organism.
⚪ Circulation: Circulatory system is open with a
contractile heart vessel with two longitudinal
vessels connected to each other by lateral
vessel.
⚪ Excretion: A single proboscis gland helps in
excretion.
⚪ Nervous System: Nervous system is not
so advanced, consisting of inter epidermal
nerve plexus. Balanoglossus has both mid-
dorsal and mid-ventral nerve cord that is
present along the entire length of the body.
Neurosensory cells are present on the
epidermis are sensitive to touch and light.
⚪ Reproduction: Sexes are separate.
⚪ Gonads are one to many.
⚪ Fertilization is external.
⚪ Direct or indirect development with a free-
swimming tornaria larva.
⚪ Special Feature: True notochord is absent.
⚪ A notochord like structure is found in
their buccal cavity, that is called ‘buccal
diverticulum’ or ‘stomochord’ (a hollow
outgrowth arises from the roof of buccal
cavity).
Connecting link: Hemichordata
y Examples:
is a connecting link between
⚪ Balanoglossus
Non-Chordata
non-chordata and chordata.

⚪ Saccoglossus
60.
Classification of Hemichordata
y It has been divided into the following two classes
on the basis of body forms:
⚪ Class Enteropneusta:
Examples: Balanoglossus, Saccoglossus
⚪ Class Pterobranchia:
Example: Rhabdopleura
Distinctive features of Hemichordata

y Presence of stomochord
y Presence of notochord-like structure known as
buccal diverticulum.
Non-Chordata
61.
Non-Chordata
Summary: Non-Chordata
Features Protozoa Porifera Coelenterata Ctenophora Platyhelminthes
Level of Organ and organ

Protoplasmic Cellular Tissue Tissue
organisation system
Symmetry Asymmetrical Asymmetrical Radial Radial Bilateral
Germ layer No layer Diploblastic Diploblastic Diploblastic Triploblastic
Coelom Acoelomate Acoelomate Acoelomate Acoelomate Acoelomate
Segmentation Absent Absent Absent Absent Absent
Digestive system Absent Absent Incomplete Incomplete Incomplete
Circulatory
Absent Absent Absent Absent Absent
system
Respiratory
Absent Absent Absent Absent Absent
system
Contractile Osculum/
Excretory system Mouth By cells Flame cells
vacuole canal system
Fertilisation Absent Internal External External Internal
Development Direct Indirect Indirect Indirect Indirect/Direct
Salient Features of Different Phyla in the Animal Kingdom
62.
Summary: Non-Chordata
Features Aschelminthes Annelida Arthropoda Mollusca Echinodermata Hemichordata
Level of or- Organ Organ Organ

Organ system Organ system Organ system
ganisation system system system
Radial (adult)
Symmetry Bilateral Bilateral Bilateral Bilateral Bilateral
Bilateral (Larva)
Triploblas-
Germ layer Triploblastic Triploblastic Triploblastic Triploblastic Triploblastic
tic
Pseudocoelo-
Coelom Coelomate Coelomate Coelomate Coelomate Coelomate
mate
Segmenta-
Absent Present Present Absent Absent Absent
tion
Digestive
Complete Complete Complete Complete Complete Complete
system
Circulatory
Absent Present Present Present Present Present
system
Respiratory
Absent Absent Present Present Present Present
system
Excretory Malpighian Proboscis

Excretory pore Nephridia Gills Absent
system tubule gland
Internal External
Fertilisation Internal Internal External External
(usually) (usually)
Develop- Indirect/
Direct/Indirect Direct Indirect Indirect Indirect
ment Direct
Salient Features of Different Phyla in the Animal Kingdom
63.
Non-Chordata
Chordata
Identifying characteristics of the chordates

y Presence of a notochord: A rod-like structure
is present in the organisms, which in the later
stages undergoes some changes to form the
vertebral column.
y Presence of dorsal hollow nerve cord: The nerve
cord lies to the dorsal of the notochord and is
always hollow.
y Presence of pharyngeal gill slits: At some stage
of the life cycle the chordates have a pair of gill
slits on the lateral side. In Pisces,they are present
throughout the life.
Classification of Chordata
Phylum Chordata is divided into three subphyla:
⚪ Subphylum Urochordata
⚪ Subphylum Cephalochordata
⚪ Subphylum Vertebrata
y Sub-phylum Urochordata
Uros-tail; chordate-notochord bearing
⚪ The organisms of this phylum are sedentary.
⚪ They are called tunicates as they are covered
by a leathery test made up of a chemical
tunicin. The notochord is only present in the
tail of the larva and disappears in the adult.
⚪ Dorsal nerve cord in the larva is replaced by
nerve ganglion in the adult.
⚪ They have gill slits for respiration.
⚪ Open circulatory system. The heart is tubular
and ventral.
⚪ Mostly hermaphrodite. Development is
indirect with a swimming larval form.
y Subphylum Cephalochordata
cephalos-head; chordata-notochord bearing
⚪ The organisms in this phylum are motile.
⚪ The notochord is present from head to tail
and is persistent throughout the life of an
organism.
⚪ Gills slits are better developed and adapted
for respiration.
Chordata
64.
⚪ Tail present throughout the life cycle.
⚪ Excretion by protonephridia. Gray Matter Alert!!!
⚪ Nerve cord dorsal and tubular.
⚪ Hermaphrodite. Retrogressive metamorphosis:
⚪ Fertilization is external. Indirect development Larval form changes from
through a free-swimming larva. a well-developed form to a
y Examples: Amphioxus less developed one. The free
y Subphylum Vertebrata swimming larva (with notochord)
⚪ The members of this subphylum are much changes into a sessile, non-
advanced than the members of the above- chordate adult. Example:
mentioned two phyla. Herdmania
⚪ Notochord is replaced by a bony structure
called the vertebral column in the adult.
⚪ Brain is enclosed in a hard bony structure
called cranium.
⚪ Exoskeleton and endoskeleton both are
present.
⚪ Digestive system is well developed.
⚪ Respiration is either by gills, skin or by the
lungs.
⚪ Circulatory system and heart are well
developed; heart having two, three or four
chambers. Gray Matter Alert!!!
⚪ Sense organs are well developed like the
eyes, ear, nose, and tongue. Progressive Metamorphosis:
⚪ Pair of kidneys are present for excretion. Larva modifies from a less
Substances that are excreted can be developed to a better developed
Ammonia, uric acid, and urea. form, as in Amphibians (Anurans).
⚪ Nervous system consists of brain and the
spinal cord.
⚪ Sexes are separate.
⚪ Fertilisation can be either external or internal.
There is no asexual reproduction.
⚪ It is divided into two divisions:
Division 1: Agnatha - Jawless Vertebrates.
Division 2: Gnathostomata-Jawed
Vertebrates.
Chordata
65.
Agnatha sucking type of mouth. Median
y Notochord is present throughout the life. fins are present but no paired
y Vertebral column is not well developed and appendages. 5-16 pairs of gill slits
is just present in the form of small arches are present. Cranium and vertebral
over the notochord. column are cartilaginous. Heart is
y It has two classes Ostracodermi and two chambered. No renal portal
Cyclostomata. system. Dorsal nerve cord and 8-10
⚪ Ostracodermi: It is an extinct class cranial nerves are present. Sexes
– ostracon – shell;derma-skin. The are separate or united ;with external
body was covered with small plates fertilisation. Development direct or
known as dermal scales and thus indirect with a larval stage. Adult
got the name Ostracodermi. Jawless move from fresh water to marine
fish-like primitive animals. Examples: water for spawning and then they
Cephalaspis die. The larva after metamorphosis
⚪ Cyclostomata: cyklos:circular; stome: return to the ocean. Examples:
mouth. Ectoparasite. Body is elongated Petromyzon (Lamprey), Myxine
eel-like with circular mouth. It has (Hagfish)
Chordata
66.
Gnathostomata
y Notochord is present in the larval forms and
is replaced by a well-developed vertebral Previous Year’s Question
column.
y Paired fins or limbs are present.
y It is divided into two super classes: A common characteristic of all
⚪ Super Class Pisces – Consists of all the vertebrates ,without exception is
fishes (1) the division of body into head,
⚪ Super Class Tetrapoda – Possessing two neck, trunk and tail
pairs of limbs. Tetrapoda is divided into four (2) their body is covered with an
classes namely Amphibia, Reptilia, Aves and exoskeleton
Mammalia. (3) they possess two pairs of
functional appendages
SUPER CLASS PISCES (4) the presence of a well
y It is divided into two classes having living developed skull
members on the basis of the endoskeleton.
⚪ Chondrichthyes: chondros -cartilage; ichthys-
fish
⚪ Osteichthyes: osteon-bone; ichthys-fish
Chondrichthyes
y Habitat-They are present in marine water.
y Body Structure- Dorsoventrally flattened.
⚪ Exoskeleton is formed of placoid dermal
scales. Endoskeleton is made up of
cartilage.
⚪ Fins are present which help in swimming.
Paired fins are pelvic and pectoral, while
unpaired fins are dorsal, ventral and caudal.
Tail fin is unequal (heterocercal). Dorsal fins
are two in number.
⚪ Notochord is present throughout the life of
the organism.
⚪ Sense Organ-Eyes have nictitating membrane.
Internal ear present.
⚪ Ampullae of Lorenzini – Electroreceptors on
dorsal surface of head to detect the vibrations
and electric field.
Chordata
67.
⚪ Lateral line system is present in the body
with rheoreceptors. .
y Digestive System: Mouth is ventral and gut opens
by the cloacal aperture.
⚪ Teeth is modified placoid scales.
⚪ Intestine has scroll valves.
⚪ Digestion is extracellular.
y Respiration: External nares are present.
⚪ Usually 5 pairs of naked gills are present
which are not covered with the operculum.
⚪ Air bladder is absent, thus they have to swim
continuously to prevent sinking.
y Circulatory System: Heart is two-chambered and
venous.
⚪ Biconvex red blood corpuscles consist of
nucleus.
⚪ They are cold-blooded. Gray Matter Alert!!!
⚪ Renal portal system is well developed.
y Nervous System: Brain has large olfactory lobe Electric Organs: Some
and small cerebellum. Chondrichthyes have electric
⚪ There are ten pairs of cranial nerves. organs for creating an electric
y Excretory System: Excretory organs are a pair of field. The electric organ is derived
kidneys which are mesonephric. from modified nerve or muscle
⚪ Excretion is ureotelic. tissue. The electric discharge
y Reproduction: In males, pelvic fins bear claspers from them is used for navigation,
which help in copulation. communication, defense and
⚪ The oviduct is known as Mullerian ducts. also for paralyzing the prey.
⚪ Gonads are in pairs. Gonoducts open into the
cloaca.
⚪ Fertilization is internal.
⚪ Females are oviparous or ovoviviparous. Rack your Brain
⚪ Development is direct without metamorphosis.
y Examples: What is the ecological importance
⚪ Scoliodon: Dog fish of Gambusia?
⚪ Carcharodon: Great white shark
⚪ Pristis: Saw fish
⚪ Trygon: Sting ray
⚪ Torpedo: Electric ray
⚪ Rhincodon: Whale shark
⚪ Chimaera: ‘Rat fish’ or ‘King of herrings’
Chordata
68.
Distinguishing Features of Chondrichthyes
y Paired fins. Gray Matter Alert!!!
y Placoid scales are present.
y Tail fin is heterocercal. Interesting facts: Chimaera-
y Paired gonads with gonoducts. Connecting link between
cartilaginous and bony fishes .
Osteichthyes
y Habitat: They are present in marine water, fresh Sting Ray-Its tail consists of
water, cold or warm waters. barbed spines. Each spine
y Body Structure: Bilaterally flattened, spindle- contains poison and can make a
shaped and streamlined. severe wound on the victim.
⚪ Paired fins are pelvic and pectoral while
unpaired fins are dorsal, ventral and caudal.
⚪ There is one dorsal fin present.
⚪ Tail fin is homocercal.
⚪ Fins are present which help in swimming.
⚪ Endoskeleton is made up of bones. In the
larval stage, it may be cartilaginous.
⚪ Exoskeleton is formed of cycloid and ctenoid
dermal scales.
y Sense Organ: Eyes have nictitating membrane.

⚪ Lateral line system is present in the body of
fishes, which includes many receptors organs
which can detect vibrations (rheoreceptor)
and electric field.
y Digestive system: Mouth is terminal. Jaws lack
teeth. Anus is present.
Chordata
69.
y Respiration: Four pairs of gills covered with
operculum is present.
y Circulatory System: Heart is two-chambered:
sinus venosus and conus arteriosus. Red blood
corpuscles consist of nucleus.
⚪ Renal portal system is well developed.
⚪ Aortic arches are present as four pairs.
⚪ Poikilothermic animals.
y Nervous System: Brain has small olfactory lobe Gray Matter Alert!!!
and large cerebellum.
⚪ There are ten pairs of cranial nerves.
Migration in fishes:
y Excretory System: Excretory organs are kidneys
Catadromous: Migration of fish
which are mesonephric.
from river to sea for breeding.
⚪ Excretory product is ammonia. Marine, bony
Examples: Anguilla
fishes excrete trimethylamine oxide and fresh
water fishes excrete ammonia.
Anadromous: Migration of fish
⚪ Urinary bladder is absent.
from sea to rivers for spawning
y Reproduction- Fishes are unisexual.
(breeding).
⚪ In males, claspers are not present.
Examples: Hilsa
⚪ Fertilisation is internal or external.
⚪ Females are oviparous.
⚪ They do not have any amnionic membrane,
hence they are Anamniota Gray Matter Alert!!!
y Examples:
⚪ Fresh water – Labeo rohita (Rohu), Clarias Accessory respiratory organs:
(catfish), Catla Supra-branchial chamber,
⚪ Marine – Hippocampus (Seahorse), Exocoetus labyrinthine organ and the
(Flying fish) respiratory membrane act as
⚪ Aquarium – Betta (Fighting fish), Pterophyllum accessory organs in Anabas
(Angel fish) which help in respiration when
the fish comes out of water for
Distinguishing Features of Osteichthyes sometime.
y Bony endoskeleton
y Air bladder present
y Homocercal tail fin
y Gills covered by operculum Rack your Brain
Which fish is considered as a

connecting link between the
fishes and the amphibians?
Chordata
70.
Table. Difference between Chondrichthyes and Osteichthyes
Features Chondrichthyes Osteichthyes
Scales Placoid scales Cycloid and ctenoid
Tail Heterocercal Homocercal
Air bladder Absent Present
Excretion Ureotelic organisms Ammonotelic organisms
Scroll valve in intestine Present Absent
Cloaca Present Absent
Ampullae of Lorenzini Present Absent
Fertilisation Internal External
CLASS AMPHIBIA
y Habitat: They are found on land as well as in
water.
y Body Structure: Body is divided into head,
trunk and tail (tail may or may not be present).
⚪ The skin is either rough or smooth and
moist due to the presence of glands on
the body.
⚪ Pigment cells called chromatophores are
present.
⚪ Two pair of limbs, therefore they are
tetrapods and pentadactyl (five digit in
each limb).
⚪ Limbs are absent in some.
Example: Ichthyophis
Chordata
71.
⚪ Paired fins absent, unpaired fins may be
present.
⚪ Exoskeleton is absent. Endoskeleton is mostly
bony.
⚪ Nictitating membranes are developed in the
eyes.
y Digestive System: Mouth is large and upper or
lower or both jaws have teeth.
⚪ Tongue is protrusible.
⚪ Teeth are homodont and polyphyodont.
⚪ Alimentary canal ends in the cloaca.
y Respiration: Respiration is by skin and lungs.
⚪ Larval forms have gills and in some organisms
like Proteus external gills are present.
y Circulatory System: Heart is three-chambered,
consisting of two auricles and one ventricle.
⚪ Aortic arches are one to three in number.

⚪ Hepatic portal and renal portal system are
well-developed.
⚪ They are cold-blooded i.e. poikilothermic.
They show aestivation in summers and
hibernation in winters.
y Nervous System: Brain is poorly developed.
Chordata
72.
⚪ Skull is dicondylic i.e., have two occipital
condyles.
⚪ Ten pairs of cranial nerves are present.
y Sense organs: Eyes with nictitating membrane
are present.
⚪ Tympanic membrane present.
y Excretory System:
⚪ Kidneys are mesonephric, large urinary
bladder is present, which open by urinary
ducts into the cloaca.
⚪ Excretory product is urea and ammonia.
⚪ Alimentary canal, urinary bladder and
reproductive tract open outside through the
cloacal aperture.
y Reproduction: Sexes are separate.
⚪ Males do not have copulatory organs.
⚪ Gonoducts open into the cloaca.
⚪ Fertilisation is external. But Salamander
shows internal fertilization.
⚪ Development is external. No embryonic
membranes are present.
⚪ Larva metamorphose into the adult.
Neoteny: When there is

deficiency of iodine in water, the
Axolotl larva of Ambystoma does
y Examples: not metamorphose into an adult
⚪ Ichthyophis-Blindworm and becomes sexually mature.
⚪ Amphiuma-Congo eel
⚪ Ambystoma-Tiger Salamander
Chordata
73.
⚪ Bufo-Toad
⚪ Rana-Frog Previous Year’s Question
⚪ Salamandra-Salamander
Necturus is
Classification of Amphibia
(1) hellbender
(2) congo eel
Living Amphibians are classified into three
(3) mudpuppy
orders:
(4) blind-worm
y Apoda: Limbless,blind and elongated.
Examples: Ichthyophis
y Urodela: Tail present, two limbs are present that
are weak.
Examples: Necturus (Mudpuppy), Amphiuma
(Congo eel)
Ambystoma-Tiger Salamander, Proteus
y Anura: Tail absent, two limbs are present.
Examples: Rana (Frog), Bufo (Toad)
Distinctive Features of Class Amphibia

y Live both on land and water
y Skin with mucous glands is seen
y Three-chambered heart
y Poikilothermic animals
y Ureotelic
CLASS REPTILIA (CREEPING OR CRAWLING

VERTEBRATES)
y Habitat: They are found both on land and in water
but mostly on land. They are creeping, burrowing
and mostly carnivores.
y Body Structure: Body is bilaterally symmetrical
and consists of head, neck, trunk and tail.
⚪ Two pair of limbs that are pentadactyl. Limbs
are absent in snakes.
⚪ Digits are provided with claws.
⚪ Endoskeleton consists of bones.
⚪ Exoskeleton consists of epidermal scales or
scutes and plates.
⚪ Skin is dry, rough without any glands. Snakes
shed their skin.
Chordata
74.
y Digestive System: Most of the reptiles are
carnivores, hence mouth is wide.
⚪ Teeth are homodont and polyphyodont. In
turtles, teeth are replaced by a horny beak.
⚪ Jacobson’s organ is present in the roof of the
mouth.
⚪ Alimentary canal terminates into the cloacal
aperture.
y Respiration: Respiration is by the lungs.
y Circulatory System: Heart is three-chambered,
consisting of two well-developed auricles and
an incomplete ventricle. In crocodile, the heart is
four-chambered.
⚪ Red blood corpuscles are nucleated.
⚪ Renal portal system is less developed.
y Nervous System: Skull is monocondylic i.e.
consists of one occipital condyle.
Chordata
75.
⚪ Cerebrum is more developed than the y Poison apparatus: Poisonous snakes
amphibians. have a poison apparatus in their heads
⚪ 12 pairs of cranial nerves are present. bearing two poison glands, their ducts
y Excretory System: Kidneys are metanephric and the fangs.
and excretory product is urea, except in ⚪ Two sac-like poison glands are
crocodile it is ammonia. present on either side of the jaw.
y Reproduction: Sexes are separate. Males These glands are modified parotid
consist of a muscular copulatory organ. glands.
⚪ Fertilisation is internal and they are ⚪ Fangs are specialised teeth that act
mostly oviparous. as a syringe to inject the poison into
⚪ Egg has a large amount of yolk the body of the victim.
(polylecithal) and cleavage is ⚪ Snake poison has neurotoxic and
meroblastic. haemotoxic effects.
⚪ Egg is covered with a leathery shell and
always laid on land.
⚪ No metamorphosis.
Chordata
76.
y Examples: Hemidactylus flaviviridis -House lizard
⚪ Varanus komodoensis-Komodo dragon Gray Matter Alert!!!
⚪ Chamaeleo chamaeleon-Chameleon
⚪ Python molurus-Python Connecting link: Seymouria is
⚪ Crocodylus palustris-Mugger Crocodile considered as a connecting
link between amphibians and
reptiles.
Peculiar features of King Cobra:

Builds nest
Exhibits cannibalism
Previous Year’s Question
Which is not a true amphibian?

Classification of Reptilia (1) Salamander
y Class reptilia is divided into two subclasses (2) Toad
consisting of living members: (3) Tortoise
⚪ Subclass Anapsida: Solid skull roof and no (4) Frog
temporal opening. Examples – Turtle,Tortoise
⚪ Subclass Diapsida: Skull with two temporal
openings separated by bones. Examples –
Lizard, Alligator, Cobra
Distinctive Features of Class Reptilia

y Dry skin with scales Rack your Brain
y Three-chambered heart, except in crocodile
y Poikilothermic Which fossil proved that birds
y Mostly uricotelic have evolved from reptiles?
Chordata
77.
CLASS AVES Rack your Brain
y They are flying vertebrates. They can also be
referred to as ‘glorified reptiles’. Name the bird that can be
y Body Structure: Body is spindle-shaped and considered as a torch bearer of
divided into four regions namely head, neck, all migratory birds?
trunk and tail.
⚪ Skin is dry, except for the presence of oil
gland or green gland at the root of the tail.
⚪ Neck is long and flexible and tail is short and
stumpy.
⚪ Two pair of limbs.
⚪ The forelimbs are modified into wings,
covered with feathers and consisting of
hollow (pneumatic) bones.
⚪ Forelimbs are used for flying.
⚪ The hindlimbs are modified for walking,
running, food capturing and swimming.
⚪ The foot consists of four clawed toes, out of
which the first one is directed backward.
⚪ Endoskeleton consists of long, pneumatic
bones.
⚪ Bone marrow is absent.
y Digestive System: Jaws are modified into a beak,
which lacks teeth.
⚪ Beak is modified for crushing, tearing, nectar
sipping, wood cutting.
⚪ Mouth leads into the alimentary canal that
has crop and gizzard.
⚪ Crop stores and softens the food while gizzard
helps in crushing and churning the food.
⚪ A three-chambered cloaca is present.
y Respiration: Respiration is by lungs.
⚪ Air sacs are connected to the lungs.
⚪ Larynx is without vocal cords. A voice box or
syrinx is present at the junction of the trachea
and bronchi.
y Circulation: Heart is four-chambered and they
are warm-blooded.
y Excretory System: Kidneys are metanephric and
Chordata
78.
consist of three lobes. Urinary bladder is absent
and excretion is uricotelic.
y Nervous System: Skull is monocondylic,
consisting of a single occipital condyle.
⚪ Cerebrum, cerebellum and optic lobes are
well developed.
⚪ 12 pair of cranial nerves are present.
⚪ Eyes are large and consist of nictitating
membrane
y Reproduction: Sexual dimorphism is seen in
them.
⚪ Males consist of a pair of abdominal testis
and females consist of only one functional
ovary. Fertilisation is internal. Development is
direct.
⚪ Eggs have a large amount of yolk and a hard
calcareous shell.
⚪ Four embryonic membranes namely amnion,
chorion, allantois and yolk sac are present.
⚪ Eggs are developed by external incubation.
Young ones that hatch, resemble the adult.
y Examples:
⚪ Corvus splendens-Crow
⚪ Passer domesticus-Sparrow
⚪ Pavo Cristatus-Peacock
⚪ Bubo bubo-Great-horned owl
⚪ Psittacula eupatria-Alexandrine Parrot
Flight Adaptations in Bird

y Shape of the body: The body is spindle-shaped,
streamlined in birds. This shape helps the bird to
offer minimum resistant to the wind.
y Compact body: The body is light dorsally but
heavy ventrally, which helps it to glide through
the air. The attachment of the wings higher up
in the body; presence of lighter body organs on
the above and heavy muscles below it helps it in
flight.
y Feathers: They are light and cover the body.
Chordata
79.
Feathers are directed backward which help
the bird to shear the friction and fly ahead. The
feathers also help in maintaining the temperature
of the body at high altitudes.
y Modification of limbs: Forelimbs are modified
into wings and help in flying. The shape of the
wings helps to reduce air pressure above and
increases air pressure below the body. Thus,
helping in flight.
y Short tail: The short tail acts as a rudder in
changing direction during flight and to check
flight.
y Endoskeleton: The presence of hollow bones
which help the body to be light in weight. The
bones are light as they are filled by air spaces
and not bone marrow.
y Air sac: They are attached to the lungs and
provide extra support to the bird for respiration
during flying and help in internal perspiration of
the bird, thus maintaining body temperature.
y Warm-blooded: This provides them greater
energy for the flight.
Classification of Aves
y Aves are classified into two subclasses.
⚪ Subclass Archaeornithes: Extinct, toothed
beak, long tail, low power of flight. Examples
– Archaeopteryx
⚪ Subclass Neornithes: Modern as well as
extinct birds. Wings well developed for flight,
tail short, teeth absent. Examples – Penguin,
Columba
Distinguishing Feature of Aves

y Fore limbs modified into wings with feathers
y Four-chambered heart
y Homeothermic
y Uricotelic
Chordata
80.
CLASS MAMMALIA
y Habitat: They are found in a large number on
terrestrial habitats.
y Body Structure: Body is divided into a head, neck,
trunk and tail.
⚪ Limbs are two with five or less than five
digits. These help in walking, running, flying,
swimming.
⚪ Exoskeleton is made up of nails, hairs, scales,
claws, hooves and horns.
⚪ Endoskeleton is made up of hard bony
structure.
⚪ Oil glands (sebaceous glands) and sweat
glands are present on the body.
⚪ The coelom consists of three cavities: One is
the pericardial cavity which lodges the heart,
second is the two pleural cavities which lodge
the lungs and the abdominal cavity with the
other parts of the body.
y Digestive System: Mouth consists of two movable
lips.
⚪ The mouth consists of a set of teeth.
⚪ They are of different types (heterodont), borne
in the socket (thecodont) and represented by
two set in lifetime (diphyodont).
⚪ Mouth leads into the alimentary canal which
ends on the anus.
⚪ A muscular partition separates the thoracic
cavity from the abdominal cavity.
Rack your Brain
y Respiration: It is by the lungs. A cartilaginous flap
is present over the glottis, known as epiglottis.
It helps to direct the food toward the food pipe Which ape is considered to be
away from the windpipe. Larynx consists of a pair the most intelligent of all?
of vocal cords.
y Circulatory System: Heart is four-chambered
having double circulation i.e. blood flows through
the heart twice in one cycle.
⚪ They are warm-blooded i.e. homeothermal.
Renal portal system is absent.
Chordata
81.
⚪ Blood consists of red blood corpuscles which
are enucleated and biconvex in shape which
help in transporting gases, white blood cells
are nucleated and irregular in shape which
help to fight against the infection and the
platelets that help in the clotting of blood.
y Nervous System: Skull is dicondylic i.e. consists
of two occipital condyles.
⚪ There is the presence of 12 cranial nerves in
the skull.
⚪ The brain consists of cerebrum and
cerebellum. Optic lobes are four in number
and called corpora quadrigemina.
⚪ Corpus callosum connects the two cerebral
hemisphere.
y Excretion: Kidneys are bean-shaped. Excretory
product is urea and excretory fluid is called urine.
⚪ Kidneys lead into the ureters which lead
into the urinary bladder and further into the
urethra.
y Reproduction: Sexes are unisexual.
⚪ Sexual dimorphism is well developed.
⚪ Males have a copulatory organ known as
penis and a pair of testes which lies in the
scrotal sac.
⚪ Females consist of a pair of ovaries.
⚪ Egg consists of very little yolk and no shell.
Fertilisation is internal and development
is internal i.e. most of them are viviparous
except Duck- billed platypus and Echidna
y Development of the foetus takes place inside
the uterus and the placenta provides nutrition to
the developing foetus from the mother. After the
birth, the young one is fed by the mother.
y Parental care is highly developed.
y Examples:
⚪ Panthera leo – Lion
⚪ Panthera tigris – Tiger
⚪ Phoca – Seal
⚪ Camelus – Camel
Chordata
82.
⚪ Bos indicus – Cow
⚪ Homo sapiens sapiens – Human
Classification of Mammalia
Mammalia is divided into two subclasses:
y Subclass Prototheria: They are oviparous i.e.
egg-laying mammals. Examples – Duck-billed
Platypus, Tachyglossus (Echidna)
y Subclass Theria: They are viviparous i.e. give birth
to young ones. Examples – Humans, Kangaroo.
It has been further divided into Metatheria and
Eutheria. Metatheria consists of infra-class
marsupialia i.e., pouched animals. Examples:
Macropus (Kangaroo), Phascolarctos (Koala), Gray Matter Alert!!!
Didelphis (opossum)
Age of Fishes-Devonian Period
Age of Amphibians-
Carboniferous Period
Age of Reptiles-Mesozoic Era
Chordata
83.
Chordata
Summary: Difference Between Non-Chordata and Chordata
Invertebrates Vertebrates
Features
(Non-Chordates) (Chordates)
Symmetry Radial, biradial or lacking Bilateral
True, pseudometamerism or
Metamerism Internal segmentation
lacking
Usually present projecting

Post-anal tail Lacking
beyond anus
Protoplasmic to organ-
Level/Grade of organization Organ-system
system
2(diploblastic), 3(Tripoblastic)
Germ layers 3(triploblastic)
or lacking
Acoelomate, pseudocoelomate
Coelom Truly coelomate
or truly coelomate
Pharynx perforated by gill

Gill slits Gill slits are absent
slits
84.
Summary: Difference Between Non-Chordata and Chordata
Present at some stage or

Notochord Notochord replaced by a backbone
made of ring-like vertebrae
Heart Dorsal, lateral or absent Ventrally placed
Hepatic portal system Absent Present
Haemoglobin In plasma or absent In red blood corpuscles
Respiration Through body surface, gills

Through gills or lungs
or tracheae
Nerve cord Solid Hollow
Nervous system Bearing Ganglia Without ganglia
Asexual reproduction Sexual reproduction

Reproduction
predominant predominant
85.
Chordata
Chordata
Summary: Subphylum Vertebrata
Features Pisces Amphibia Reptilia Aves Mammalia
Mainly ter-
Aquatic and restrial and
Habitat Aquatic Aerial Terrestrial, aquatic
terrestrial sometimes
aquatic
Hopping on
Creeping and Flying in air
land and Running, walking on
Locomotion Swimming running on and walking
swimming in land
land on land
water
Endoskeleton Endoskeleton Endoskeleton

Endoskeleton and
Skeleton and exoskel- Endoskeleton and exoskel- and exoskel-
exoskeleton
eton eton eton
Digestion Extracellular Extracellular Extracellular Extracellular Extracellular
Gills,
Respiration Gills Lungs Lungs Lungs
skin,lungs
Some Characteristics of Different Classes of Subphylum Vertebrata
86.
Summary: Subphylum Vertebrata
Three-
chambered
heart,
Three- Three-
Two- exception Four-
chambered chambered
chambered crocodile chambered heart,
Circulation heart, heart,
heart, (Four- Poikilothermic
Poikilothermic Poikilothermic
Poikilothermic chambered animals
animals animals
heart),
Poikilothermic
animals
Ammonotelic,
Excretion Ammonotelic Uricotelic Uricotelic Ureotelic
Ureotelic
Reproduction:
Unisexual Unisexual Unisexual Unisexual Unisexual
Sexes
Fertilisation External External Internal Internal Internal
Development Indirect Indirect Direct Direct Direct
Examples: Rohu, Catla, Toad, Sala- Alligator, Tor- Pigeon, Os-

Giraffe, Whale
Anabas mander toise trich
Some Characteristics of Different Classes of Subphylum Vertebrata
87.
Chordata
SOLVED EXERCISE
Q1 Which one the following Phylum does not show organ-system of

organisation?
(1) Porifera (2) Annelida (3) Arthropoda (4) Mollusca
A1 (1)
Porifera has a cellular level of organisation.
Q2 A complete digestive system has

(1) one opening (2) no opening
(3) two openings (4) three openings
A2 (3)
Mouth and Anus are present.
Q3 Bilateral symmetry is shown by

(1) Coelenterates (2) Ctenophores (3) Sponges (4) Annelida
A3 (4)
Annelids can be divided into two identical halves in one plane only. Coelenterates
and Ctenophores are radially symmetrical while Sponges are asymmetrical.
Q4 Coelenterates are
(1) triploblastic (2) coelomate
(3) diploblastic (4) asymmetrical
A4 (3)
They have two germ layers.
Animal Kingdom
88.
Q5 Aschelminthes are
(1) Acoelomates (2) Diploblastic
(3) Pseudocoelomate (4) Coelomate
A5 (3)
Mesoderm is present in scattered pouches.
Q6 Notochord is absent from

(1) Porifera to Pisces (2) Coelenterata to Echinodermata
(3) Pisces to Mammals (4) Porifera to Echinodermata
A6 (4)
They are non-chordates and lack notochord. Pisces to mammals have a
notochord and are later replaced by vertebral column.
Q7 Pisces secrete nitrogenous waste in the form of

(1) Sulphates (2) Ammonia (3) Urea (4) Uric acid
A7 (2)
Ammonia is dissolved in water and is excreted out.
Q8 Blood will flow at low and high pressure in

(1) Cockroach (2) Tiger (3) Snail (4) Prawn
A8 (2)
Closed system has blood flowing at low and high pressure through blood
vessels.
Animal Kingdom
89.
Q9 Book lung is present in
(1) Spider (2) Octopus (3) Leech (4) Nereis
A9 (1)
Respiratory organ of some Arthropods.
Q10 Extracellular digestion occurs in

(1) Sea Anemone (2) Earthworm (3) Leech (4) Sponge
A10 (4)
Digestion takes place outside the cell in an organ cavity.
Q11 Malpighian tubules are

(1) excretory organs of insects (2) excretory organs of annelids
(3) respiratory organs of insects (4) respiratory organs of annelids
A11 (1)
Present in insects for removal of waste products.
Q12 What is common among silverfish, scorpion, crab and honey bee?
(1) Jointed legs (2) Metamorphosis
(3) Compound eyes (4) Poison glands
A12 (1)
Jointed appendages are present in Arthropoda.
Animal Kingdom
90.
Q13 Sycon belongs to a group of animals, which are best described as
(1) unicellular or acellular
(2) multicellular without any tissue organization
(3) multicellular with a gastrovascular system
(4) multicellular having tissue organization, but no body cavity
A13 (2)
They show cellular level of organization.
Q14 Ommatidia serve the purpose of photoreception in

(1) cockroach (2) frog (3) humans (4) sunflower
A14 (1)
Serve as a sensory organ in Arthropoda.
Q15 Which one of the following is a matching pair of an animal and a certain phe-
nomenon it exhibits?
(1) Pheretima – Sexual dimorphism
(2) Musca – Complete metamorphosis
(3) Chameleon – Mimicry
(4) Taenia – Polymorphism
A15 (2)
Show complete metamorphosis i.e., egg, larva, pupa and adult.
Q16 Given below are four matchings of an animal and its kind of respiratory or-
gan:
(A) Silverfish – Trachea (B) Scorpion – Book lung
(C) Sea squirt – Pharyngeal slits (D) Dolphin – Skin
The correct matchings are
(1) (A) and (B) (2) (A), (B) and (C) (3) (B) and (D) (4) (C) and (D)
Animal Kingdom
(2)
A16 Respiratory organ of Dolphin is lungs.
91.
Q17 In which of the following animals the nerve cell is present but brain is absent?
(1) Sponge (2) Earthworm (3) Cockroach (4) Hydra
A17 (4)
It has nerves but no nerve cells.
Q18 In which of the following animals dimorphic nucleus is found?

(1) Amoeba proteus (2) Trypanosoma gambiense
(3) Plasmodium vivax (4) Paramecium caudatum
A18 (4)
It has macronucleus and micronucleus.
Q19 In Hydra, waste material of food digestion is removed from

(1) body wall (2) flame cells
(3) mouth (4) tentacles
A19 (3)
Undigested food removed from mouth.
Q20 The nephridia in earthworm are analogous to

(1) nematoblasts of Hydra (2) flame cells of Planaria
(3) gills of prawn (4) trachea of insects
A20 (2)
Excretory organs of earthworm and Planaria
Animal Kingdom
92.
Q21 Uricotelism is found in
(1) mammals and birds (2) fish and fresh water protozoans
(3) birds, land reptiles and insects (4) frogs and toads
A21 (3)
Uricotelism means excretion of uric acid.
Q22 One of the following is a very unique feature of the mammalian body
(1) homeothermy (2) presence of diaphragm
(3) four-chambered (4) Blood circulation
A22 (2)
Unique feature of mammals is the presence of diaphragm.
Q23 Both male and female pigeons secrete milk through

(1) salivary glands (2) modified sweat glands
(3) crop (4) gizzard
A23 (3)
Pigeons are noted for their unique ability to produce pigeon’s milk.
Q24 Eutherians are characterised by

(1) hairy skin (2) true placentation
(3) ovoviviparity (4) glandular skin
A24 (2)
Eutheria contains the placental mammals, such as humans.
Animal Kingdom
93.
Q25 What is common in a whale, bat and rat?
(1) Absence of neck
(2) Muscular diaphragm between thorax and abdomen
(3) Extraabdominal testes to avoid high temperature of body
(4) Presence of external ears
A25 (2)
Whale, bat and rat are mammals. Diaphragm is present in mammals.
Q26 Bullfrog of India is

(1) Rana tigrina (2) R. sylvatica
(3) R. ecatesbeiana (4) R. esculenta
A26 (1)
The common Indian bull frog is Rana tigrina.
Q27 Feet of kingfisher are modified for

(1) wading (2) perching (3) running (4) catching
A27 (1)
Hindlimbs are variously modified for various functions like perching, grasping
and wading.
Q28 Pneumatic bone is found in

(1) shark (2) Rana (3) pigeon (4) whale
A28 (3)
Pneumatic bones are present in birds to make them light weight.
Animal Kingdom
94.
Q29 A common characteristic of all vertebrates without exception is
(1) the division of body into head, neck, trunk and tail
2) their body covered with an exoskeleton
(3) the possession of two pairs of functional appendages
(4) the presence of well developed skull
A29 (4)
The subphylum vertebrata have a well-developed central nervous system.
Q30 Annual migration does not occur in the case of

(1) Arctic tern (2) Salmon
(3) Siberian crane (4) Salamander
A30 (4)
Others show migration for breeding or for surviving unfavourable conditions.
Animal Kingdom
95.

Animal Kingdom

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Animal Kingdom

Animal Kingdom – Characteristics of Classification

Gray Matter Alert!!!

Marine phyla: Phylum Echinodermata,

Animal Kingdom – Characteristics of Classification

y Blind sac plan: In this case, the multicellular

Animal Kingdom – Characteristics of Classification

y Metameric segments (True segmentation): The

Animal Kingdom – Characteristics of Classification

y Pseudocoelomates: The mesoderm is present in

y Coelomates (Eucoelomates): It is a body cavity

filled with blood and known as haemocoel.

y Exoskeleton: It is present outside the body. It is

Animal Kingdom – Characteristics of Classification

Animal Kingdom – Characteristics of Classification

Based on the distribution of yolk in the cytoplasm

y Homeotherms (Warm-blooded animals): The

Table. Different modes of respiration in animals

Animal Kingdom – Characteristics of Classification

• Body surface Body surface Sponge, sea anemone

• Branchial Gills Garden snail, rohu

• Cutaneous Skin Earthworm, frog

• Tracheal Trachea Cockroach

• Booklung Booklungs Spider, scorpion

• Buccopharyngeal Buccopharyngeal cavity Frog, toad

Toad, snake, crocodile,

y Closed circulation: In such a circulation, the

Gray Matter Alert!!!

Dual Excretion: Some animals

Excretory Organs Animals

Animal Kingdom – Characteristics of Classification

• Protonephridia (flame cells) Flatworms

• Intracellular tubes Roundworms

• Antennary/green glands Prawn

• Malpighian tubules Cockroach

• Coxal gland Scorpion and spider

• Kidneys Garden snails, alligator

rise to a young one of its own kind is known as

Animal Kingdom – Characteristics of Classification

This system placed all prokaryotes in Kingdom

Monera and unicellular eukaryotes were placed

Broad classification of kingdom Animalia based on common fundamental characters.

Animal Kingdom – Characteristics of Classification

Summary: Characteristics of Animal Kingdom

 The choanocyte consists of ovoid cell with Protozoa and Porifera.

carried out of the body. There are three types of

Ingressing water 

⚪ Sycon: It is a complex type of canal system

Ingressing water 

Ingressing water 

y Nutrition: Digestion is intracellular, and food

Classification of Phylum Porifera:

y Distinctive Features Over Protozoa

PHYLUM COELENTERATA OR CNIDARIA

It was discovered by Trembley.

y Excretion: Ammonia is the chief excretory

Classification of Phylum Cnidaria

Distinctive features over Porifera

unwanted matter is thrown out of the mouth

as red moonga stone.

The choanocyte consists of ovoid cell with Protozoa and Porifera.