INTRODUCTION TO BIOLOGY

Ql. What is Science?

Ans. Science is the study in which observations
are made, experiments are done and logical
conclusions are drawn in order to understand the
principles of nature.
Q2. Why the scientific knowledge was classified
into different branches?
Ans. In ancient times, all the scientific informations
were included under one head i.e. Science. With
the passage of time scientific informations
increased many folds and this enormous scientific
knowledge was then classified into different
branches like, biology, physics, chemistry,
mathematics etc.
Q3. What Dr. Abdul Salam told about scientific
knowledge?
Ans. According to Dr. Abdul Salam, scientific
knowledge is the common heritage of mankind.
Q4. What is biology? Describe major divisions of
biology.
Ans. Biology: The scientific study of life is called
biology.
Explanation of word Biology:

The word biology has been derived from two

Greek words:-
(a) Bios meaning life.
(b)Logo meaning thought or reasoning.
What we study in biology?
The study of biology helps us in studying the
structures, functions and related aspects of living
organisms. It also provides information and
remedies to human problems regarding health,
food, environment etc.
Major Divisions of Biology
Biology can be divided into three major divisions:-
(i) Zoology
This division of biology deals with the study of
animals.
(ii) Botany

This division of biology deals with the study of

plants.
(iii) Microbiology
This division of biology deals with the study of
microorganisms, e.g. viruses, bacteria, etc.
Q5. Define different branches of biology.
Ans. In order to study all (he aspects of life, major
divisions of biology arc further divided
into different branches as defined below:
(i) Morphology
This branch deals with the study of form and
structure of living organisms.
(ii) Anatomy:
The study of internal structures is called anatomy.
(iii) Histology
The microscopic study of tissues is called
histology.
(iv) Cell biology
The study of structures and functions of cells and
cell organelles is called cell biology. This v.
branch also deals with the study of cell division.
(v) Physiology
This branch deals with the study of the functions of
different parts of living organisms.
(vi) Embryology
It is the study of the development of an embryo to
a new individual.
(vii) Taxonomy
It is the study of the naming and classification of
organisms into groups and
subgroups.
(viii) Genetics
The study of genes and their role in inheritance is
called genetics. Inheritance means the
transmission of characters from one generation to
the other.
(ix) Paleontology
It is the study of fossils, which are the remains of
extinct organisms.

(x) Environmental Biology

It deals with the study of the interactions between
the organisms and their environment.
(xi) Biotechnology
It deals with the practical application of living
organisms to make substances for the welfare of
mankind.
(xii) Socio-Biology
This branch deals with the study of social behavior
of animals that make societies.
(xiii) Parasitology
This branch deals with the study of parasites.
(xiv) Immunology
It is the study of immune system of animals, which
defends the body against invading microbes.
(xv) Entomology
It is the study of insects.
(xvi) Pharmacology
It is the study of drugs and their effects on the
systems of human body.
(xvii) Molecular Biology
It deals with the study of molecules of life; e.g.
water, proteins, carbohydrates, lipids and nucleic
acids. OR It deals with the structure of organisms,
the cells and their organelles at molecular level.
Q6. What are Parasites?
Ans. Parasites are the organisms that take food
and shelter from living hosts and in return, harm
them, e.g., viruses, bacteria and parasitic worms.
Q7. What are the major biological issues today?
Ans. Human population growth, infectious
diseases, addictive drugs and the pollution are the
major biological issues today.
Q8. Describe the relationship of biology to other
sciences.
Ans. Introduction
The interrelationship among different branches of
science cannot be denied. Biological informations
relate to the other branches of science as well. For
example, when studying the process of movement
in animals, the biologists have to refer to the laws
of motion in Physics. This forms the basis of
interdisciplinary sciences.
(1) Bio-physics
It deals with the study of the principles of physics,
which are applicable to the biological phenomena.
Example Similarity between the working principles
of lever in Physics and limbs of animals in Biology.
(ii) Bio-chemistry
It deals with the study of the Chemistry of different
chemical compounds and
processes occurring in living organisms.
Example The study of basic metabolism of
photosynthesis and respiration involves the
knowledge of Chemistry.
(iii) Bio-mathematics / Biometry.
It deals with the study of using mathematical
techniques and tools in biological work.
Example
To analyze the data gathered after experimental
work, biologists have to apply the rules of
mathematics.
(iv) Bio-geography
It deals with the study of occurrence and
distribution of different species of living organisms
in different geographical regions of the world.
Application of Biogeography
It applies the knowledge of the characteristics of
particular geographical regions to
determine the characteristics of living organisms
found there.
(v) Bio-Economics
It deals with the study of organisms from
economical point of view.
Example

The cost value and profit value of wheat can be

calculated through this branch and benefits or
losses can be determined.
Q9. Briefly describe the careers in biology.^
Ans. The following are the careers that a student
of biology can plan to adopt.
(i) Medicine / Surgery
(a) Medicine deals with diagnosis and treatment of
diseases in human.
(b) In Surgery, the parts of body may be repaired,
replaced or removed.
For example, the removal of stones through renal
surgery, transplantation of kidney, liver etc.
(c) Both these professions are studied in the same
basic course (MBBS) after higher
secondary education and the students go for
specializations.
(ii) Fisheries
(a) It deals with the study of fish production and
enhancing the quality and quantity of fish
production.
(b) Professionals of fisheries are employed in
fisheries departments of Pakistan.
(c) This profession can be adopted after the
bachelor or masters level study of zoology and
fisheries.
(iii) Agriculture
(a) It deals with the study of food crops and
animals which are the source of food.
(b) An agriculturist works for the betterment of
crops like wheat, rice, corn etc and animals.
(c) This professional course can be adopted after
the higher secondary education in biology.
(iv) Animal Husbandry
(a) It is the branch of agriculture concerned with
the care and breeding of domestic animals
(livestock) e.g. cattle, sheep etc.
(b) This professional course can be adopted after
the higher secondary education in biology.
(v) Horticulture
(a) It deals with the study of art of gardening.
(b) A horticulturist works for the betterment of
existing varieties and for the production of new
varieties of ornamental plants and fruit plants.
(c) This professional course can be adopted alter
the higher secondary education in biology.
(vi) Farming
(a) It deals with the development and maintenance
of different types of farm.
For example, in some farms, animal breeding
technologies are used for the production of
animals which are better protein and milk source.
(b) In poultry farms, chicken and eggs are
produced.
(c) In fruit farms, different fruit yielding plants are
grown.
This profession can be adopted after the course of
agriculture, animal husbandry or fisheries.
(vii) Forestry
(a) It deals with the study of natural forests and
advises to the government for planting
and growing artificial forests.
(b) This professional course can be adopted after
the higher secondary education in biology or after
bachelor level study of zoology and botany.
(viii) Biotechnology
(a) It deals with the study and work for the
production of useful products through
microorganisms.
(b) This professional course can be adopted after
the higher secondary education in biology or after
bachelor level studies of zoology or botany.
Q10. Explain the Islamic concept about origin of
life.(Lahore board 2011 G p (short question)
Ans. Allah hints about the origin and
characteristics of living organisms at many places
in the Holy Quran. Human beings have been
instructed to expose the unknown aspects of life
after getting the hints from the verses.
Verse No. 1
Creation of life from water
We made everything from water.(Sura: Ambia,
Verse: 30)
The above verse hints at the common origin of all
living things in water and water makes 60-70% of
the composition of protoplasm of all living things.
Verse No. 2
Creation of Life from Clay & Method of
Development
He made man from clay like the potter. (Sura:
Rehman, Verse: 14)
Verse No.3
In another verse, God says:
HiJ,
Then fashioned we the drop a clot, then fashioned
we the clot a little lump, then fashioned we the little
lump bones, then clotted the bones with flesh.
(Sura: Al Mominoon, Verse: 14)
In both above verses, we find the events that
occurred in the creation of human beings and
Allah also hints at the method of the development
of animals including human beings.
Verse No. 4

Concepts of Classification

“Allah hath created every animal from water,

then some of them creep up over their bellies,
others walk on two legs and others on four. Allah
creates what He pleases.”

(Sura: Al-Nur, Verse: 45)

This verse describes the common origin and

modification of organisms and also supports
the modem concepts of classification.

Qll. Describe the contributions of different Muslim

scientists in the
field of Biology.

Ans. Muslim scientists have made great

contributions to the science and we
are aware of their success in different fields of
science.

(i) Jabir Bin Hayan (721-815 AD) (Lahore board

2012 G I)

(a) He was bom in Iran and practiced medicine in

Iraq.

(Jabir Bin Hayan)

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(b) He introduced experimental investigations in

chemistry and also wrote a number of
books on plants and animals.

(c) His famous books are “Al-Nabatat” and

“Al-Haywan”.

(ii) Abdul Malik Asmai (740-828 AD) (Lahore board

2012 g ii)

♦> He is considered the first Muslim scientist

who studied animals in detail.

❖ His famous writings include “Al-Abil

(camel)” , “Al-Khail (horse)”, “Al-
Wahoosh
(animal)” and “Khalqal-ansan”
(d) Bu All Sina (980-1037 AD) (Lahore board 2011
G II)

♦♦♦ He is honoured as the founder of

medicine and called

as Avicenna in the west.

❖ He was a physician, philosopher, astronomer

and
poet.

❖ One of his best books “Al-Qanun fial-

Tib” is
known as the canon of medicine in west.

Q12. Describe separate and comparative

description of all the levels of biological
organization.

Ans. Biological organization at different levels

(1) Subatomic and Atomic level

(a) Atoms and Elements

❖ All types of matter are made up of elements.

♦♦ There are about 92 kinds of elements

found in nature.

❖ Each element is made up of a single kind of

atoms (‘a’: not, ‘tom’: cut).
❖ These atoms are actually the structures
formed by many subatomic particles.

❖ The most stable subatomic particles are

electrons, protons and neutrons.

(b) Bioelements

❖ Out of the 92 elements, 16 elements take part

in making the body mass of a living
organism called bioelements.

❖ Only six (0, C, H, N, Ca & P) make 99% of

total mass. These are known as major
elements.

❖ Other ten (K, S, Cl, Na, Mg, Fe,Cu, Mn, Zn &
I) collectively make 1 % of the total mass.
These are called trace elements.

(i) Oxygen = 65% (ii) Carbon = 18% (iii) Hydrogen

=10%

(iv) Nitrogen = 3% (v) Calcium = 2% (vi)

Phosphorous = 1%

(vii) Others = 1%

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(2) Molecular Level

(a) Biomolecules

❖ In organisms, bioelements usually do not

occur in isolated forms rather they combine
through ionic or covalent bonding.

❖ The stable particle formed by such bonding is

called as molecule, if occurring in the
bodies of living organisms they are called
biomolecules.

❖ An organism is formed by enormous number

of biomolecules of hundreds of different
types.

These molecules are the building material and are

themselves constructed in great variety
and complexity due to specific bonding
arrangements.

Classification of Biomolecules
❖ Biomolecules may be classified as:

a) Micromolccules

These are molecules with low molecular weight

e.g. glucose, water etc.

b) Macromolecules

These are molecules with high molecular weight

e.g. starch, proteins, lipids etc.

(3) Organelle and Cell Level (Lahore board 2011

G I) (short question)

(a) Organelle Formation

❖ Biomolecules assemble in a particular way

and form organelles.

(b) Cell Formation

♦> The organelles are actually sub-cellular

structures and when they assemble together, cells
are formed.

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(c) Division of Labour within the Cell

❖ Each type of organelle is specialized to

perform a specific function e.g. mitochondria are
specialized for cellular respiration and ribosomes
are specialized for protein synthesis. In this
way, functions of the cell are accomplished by
these specialized structures. It is an example
of the division of labour within the cell.

No. of Cells

❖ In the case of Prokaryotes and most protists,

the entire organism consists of a single cell.

❖ In the case of most fungi, all animals and

plants, the organism consists of upto trillions of
cells.

(4) Tissue Level

(a) Definition

❖ A group of similar cells specialized for the

performance of a common function.

(b) Explanation

❖ Each cell in a tissue carries on its own life

processes (e.g. cellular respiration, protein
synthesis) and also some special processes
related to the function of the tissue.
(c) Examples

❖ There are different types of plant tissues, e.g.

epidermal tissue, ground tissue etc. Animal
tissues are also of different types e.g. nervous
tissues, muscular tissues etc.

: Figure 1.3: Level* of

orgard^tion

""jOrg»n and

'■.''I . 'V''\ , •desman svslorri level

■v\ '•

- ® s.

'Cell "
level

(5) Organ and Organ System Level

Organ Level

(a) Formation of Organ Level

❖ More than one type of tissue having related
functions are organized together to form
organ.

Chapter Biology 9th

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❖ Different tissue of an organ perform their

specific functions and these functions
collectively become the functions of that organ.

(b) Example

❖ For example, stomach is an organ specialized

for the digestion of proteins & storing food.

❖ Stomach have:-

(i) Epithelial (glandular) tissues which secrete the

gastric juice.

(ii) Muscular tissues perform contractions of

stomach walls for grinding of food, mixing
enzyme with food and moving food to posterior
end. So two tissues perform their functions
which collectively become the function of stomach.

(iii) Connective tissue which help to connect other

tissues together
(iv) Nervous Tissue: The action of stomach is co-
ordinated by this tissue.

Organ System Level

(a) Formation of Organ System Level

❖ Different organs performing related functions

are organized together in the form of an
organ system.

❖ In organ system, each organ carries out its

specific function and the functions of all
organs appear as the function of the organ
system.

(b) Example

Digestive system carries out process of digestion.

It consists of oral cavity, stomach,
small intestine, large intestine, liver and pancreas

❖ The organ system level is less definite in

plants as compared to animals.

(6) Individual Level .

(a) Formation of Individual Level

❖ Different organs and organ systems are

organized together to form an individual
*V (organism).
❖ In an organism, various organs and organ
systems are organized in such a way that all the
functions, processes and activities are
coordinated.

(b) Example

❖ During continuous and hard exercise, rate of

respiration and heart beat are increased and
supplies more oxygen and food to muscles which
is needed for continuous work.

(7) Population Level

(a) Formation of Population Level

❖ A group of organisms of same species located

at the same place, in the same time is
called population.

(b) Example

Human population in Pakistan in 2010 comprises

of 173.5 million individuals.

Chapter Biology 9th

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(8) Community Level

(a) Introduction

A community is an assemblage of different

populations interacting with one another
within the same environment.

(b) Example

❖ A forest may be considered as a community. It

includes different plants, microorganisms,
fungi and animal species.

❖ Communities are collections of organisms, in

which one population may increases and
others may decrease.

❖ Some communities are complex e.g. forest

and pond community.

❖ Some communities are simple e.g. a fallen log

with various populations under it.

❖ Simple communities have limited number and

size and any change in biotic or abiotic

factors may have drastic and long lasting effects.

C

(9) Biosphere Level

The part of the earth inhabited by organisms’
communities is known as biosphere. It
constitutes all ecosystems (area where living
organisms interact with non-living components
of the environment) and is also zone of life on
ea*ih.

Q13. Give comparison in cellular, colonial and

multicellular organization.

Ans. Five Major Groups of Organisms

All organisms have been divided into five major

groups i.e. prokaryotes, protists, fungi,
plants and animals.

Types of Cells

All organisms are made of cell.

There are two basic types of cells.

Prokaryotic Cells:

Cells lacking membrane bounded nucleus and

organelles are called prokaryotic cells e.g.
bacteria & cyanobacteria.

Eukaryotic Cells:

Calls having membrane bounded nucleus and

organelles are called eukaryotic cells e.g.
animal cells, plant cells etc.
Cell Organization:

In the living organisms, the cells organize in three

ways to make bodies of organisms.

Cells make unicellular, colonial and multicellular

organizations and the organisms formed
through these organizations are unicellular
organisms, colonial organisms and multicellular
organisms respectively.

a) Unicellular organization: (Lahore board 2012 c

ip

❖ In unicellular organisms, only one cell makes

the life of an organism.

❖ All the life activities are carried out by the only
cell.

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♦> Examples: Amoeba, Paramecium, Euglena
etc.

b) Colonial Organization:

❖ In colonial type of cellular organization, many

unicellular organisms live together but do
not have any division of labour among them.

❖ Each unicellular organism in a colony lives its

own life and does not depend on other
cells for its vital requirements.

❖ Volvox is a green alga found in water is an

example of colonial organization.

❖ Hundreds of volvox cells make a colony.

Figure 1.5 volvox colony

c) Multicellular Organization:

In multicellular organization, cells are organized in

tissues, organs and organ systems.
Examples

Mustard Plant: Brassica Campestris:

(a) Sowing
❖ It is sown in winter and produces seed at the
end of winter.

(b) Importance

❖ Its plant body is used as vegetable & its seeds

are used for extracting oil.

(c) Body Parts

❖ Plant body consists of two parts:-

a) Vegetative Parts:

❖ It includes roots, stems, branches and leaves.

❖ These do not take part in sexual reproduction.

b) Reproductive Parts:

Flowers are reproductive parts of plant because

they take part in sexual reproduction and
produce fruits and seeds.

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Frog: Rana tigrina:

(a) Body

❖ The body of frog also shows multicellular

organization.

❖ The body is made up of organ systems.

❖ Each organ system consists of related organs

❖ All the organs are made of specific tissues

(epithelial, glandular, muscular, nervous etc.)

Q.14: What do you know about species?

Ans. A species is defined as a group of organisms

capable of interbreeding and producing
fertile offspring.

Q.15: What is habitat?

Ans. Habitat means the area of the environment in

which organism lives.