TOPIC

TYPE OF ACTIVITY
ACTIVITY TITTLE
GENERAL
Systematics
Concept Notes
BIOLOGY

Classification System and Binomial

2
Nomenclature
LEARNING TARGET Identify the different classification systems
Perform binomial nomenclature as a way of
naming organisms
REFERENCE/S Exploring Life Through Science, General
Biology 2
AUTHOR/S Ramos, A.C. et al
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01 WEEK 5-6 | 5 - 16 OCT 2020

 HISTORICAL VIEW ON LIFE’S CLASSIFICATION SYSTEM
Shopping is like studying biodiversity on Earth. It will be difficult to describe and study
organisms if they are not categorized in an organized manner. It would be definitely
be easier if similar organisms are placed together in one group.

Scientists claimed that the number of actual species that have not been discovered
and identified, is close to around 8.7 million with 6.5 million species on land and
2.2 million in oceans ( Census Marine Life, August 24, 2011). So far, scientist have only
identified, named, and classified almost 2 million kinds of organisms on Earth.

Number of Described Species on Earth

Species Number
Bacteria 4000
Protists (algae, protozoa) 80 000
Animals - vertebrates 52 000
Animals - invertebrates 1 272 000
Fungi 72 000
Plants 270 000
SLIDE NO. Total described species 1 750 000

02 Possible total of all species (including unknown species)

By the UN Convention on Biological Diversity
14 000 000
 The process of grouping organisms using a multilevel approach based on their
similarities is called classification.

Taxonomy on the other hand, is a study of naming extant organisms (those that are
living today) as well as the extinct (those that have died) and classifying them into
logical groups. It comes from the root word taxis, which mean “arrangement”.

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 CLASSIFICATION SYSTEMS
 Aristotle’s Classification System | ARISTOTLE (300 BC)
• He developed a primeval system based on harmful and nonharful organisms or
edible and nonedible plants.
• He classified organisms into those with red blood and those without and organism as
plants or animals.
• He also classified animals based on were they lived such as in land, water, or air.
• He subdivided plants based on three categories using stem differences.
• This crude system lasted for over 2. 000 years.

Aristotle’s System

Plants Animals

Soft Stems (herbs) Air dwellers

Several woody stem

Land Dwellers
(shrubs)

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One woody stem
Water Dwellers
(trees)
 CLASSIFICATION SYSTEMS
 Polynomial System of Classification | GREEKS and ROMANS

• Expanded Aristotle’s classification system by creating basic units – cats, oaks, and
horses.
• These units began to be called as genera, which is a Latin name for “group”
• In the Middle Ages, these names began to systematically written down by scholars.
The cats were assigned with a name of Felis, horses wit Equus, and oaks as Quercus.
• Before mid-1700s, biologists affixed a series of descriptive terms to the name of the
genus if they wanted to refer to a certain kind of organism within it, known as species.
These many phrases, starting with the genus, are known as polynomials, which is
made up of about 12 or more Latin words strung together.
• Example, naming a bee using a polynomial system is called Apis pubescents, Thorace
subriseo, Abdomine fusco, Pedibus posticus glabi, and Untrinque margine ciliatus.
• This system was then replaced by the binomical system introduced by Carolus
Linnaeus.

Example:
• Ranunculus calycibus, retroflexus, pedulculis falcatis, caule erecto, folis compositis,
“The buttercup with bent-back sepals, curved flower stalks erect stems and
SLIDE NO. compound leaves”

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 CLASSIFICATION SYSTEMS

 The Linnean System of Classification | CAROLUS LINNAEUS (1758)

• In 1758 a Swedish doctor and botanist, Carolus

Linnaeus, published the 10th edition of his book,
Systema Naturae.
• Binomial Nomenclature, means “two names”. This
scientific naming of organisms has standardized the
organisms are classified and named, and is still being
used today.
• Carl von Linne is the founder of modern taxonomy. In
his fondness for his system of classification, he even
converted his name into Carolus Linnaeus.

Taxonomy does not only involve naming organisms properly but also
categorizing organism into logical groups. Linnaeus was also responsible for
proposing the placement of organisms into a seven-level hierarchal system for
classifying organism based on their form and structure. He categorized organisms
from the general to the most specific level, using the seven-level hierarchical
SLIDE NO. system. The levels are kingdom, phylum, class, order, family, genus, and species.

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 THE
BINOMIAL NAMING
OF ORGANISMS

Linnaeus’ legacy is the assigning of two Latin A genus (plural: genera) is a

names to a certain species, known as binomial classification or grouping that
nomenclature, (bi mean “two”, nomen means contains similar, closely related
“name” and calatus means “list”. organism.
For example, lions, tigers,
In man’s scientific name, Homo sapiens, the first leopards, and jaguars are all
word “homo” is its genus. classified under the genus,
Panthera.

Panthera, animals share

 Tiger (Panthera tigris) common characteristics such
 Leopard (Panthera pardus) as large body size, ability to
 Lion (Panthera leo) roar, being a keen swimmer,
 Jaguar (Panthera onca) and sharp teeth and
SLIDE NO. retractable claws for hunting

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prey even much larger than
their own size.
 How do you write a scientific name using the
BINOMIAL NOMENCLATURE?
Rules for writing a scientific name using binomial
nomenclature:

1 2 3 4
The genus is the Always Species name is Written
1st name and capitalize the always underlined or
species is the genus. lowercase. italicized
2nd name.

Homo sapiens Homo sapiens

(Human) (Human)
Escherichia coli Homo sapiens
(Bacteria) Escherichia coli
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(Bacteria)
 THE
HIERARCHY OF
TAXONOMIC CLASSIFICATION

The classification system used by the scientists today are based from the legacy of Carolus Linnaeus.
During his time, the classification system has seven levels or taxa arranged from the most general to the
most specific – kingdom, phylum, or division in plants, and fungi, class, order, family, genus, and species.
Each level is said to be nested. Which means that a particular level is a subset of the level above it.

Taxonomic Ranks and Examples of Species

Animal Example Taxonomic Rank Plant Example
Eukarya Domain Eukarya
Animalia Kingdom Plantae
Chrodata Phylum Angiospermophyta
Mammalia Class Eudicotidae
Primtae Order Ranunculales
Huminidae Family Ranunculacae
SLIDE NO. Homo Genus Ranunculus

09 sapiens
Human
Species
Common Name
acris
Buttercup
 GENERAL

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10 SPECIFIC
 THE
HIERARCHY OF
TAXONOMIC CLASSIFICATION

Taxonomic hierarchy showing Aloe vera’s taxonomic classification. As you trace its connection in the
different levels of classification, the number of organisms it shares characteristics will decreases.

Taxonomic Rank Aloe vera Classification Number of Species

Domain Eukarya Several Million
Kingdom Plantae ~375 000
Phylum Anthophyta ~235 000
Class Liliopsida ~65 000
Order Liliales ~1200
Family Asphodelacaea ~785
Genus Aloe 500

SLIDE NO. Species Aloe vera 1

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 SYSTEMATICS:
TRACING OUR LIFE’S HISTORY

The tree of life concept was first proposed by Charles Darwin in his book On the Origin of
Species, where he used a tree as an analogy to demonstrate that all of the species
originated from one or two species.

Charles Darwin’s drawing of the tree of life

SLIDE NO. as a metaphor for the evolutionary tree

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found in his Transmutation Notebook.
 SYSTEMATICS:
TRACING OUR LIFE’S HISTORY

 Ernst Haeckel coined the term “Tree of Life”

 The tree was also know as the “Evolutionary tree of Life”, which was also used in the
field of taxonomy as basis for classifying organisms.
 The phylogenetic species system of classification emerged in the 1940s, the
concept believed that classifying organisms should not only rely on showing the
relationships of organisms based on physical similarities and differences but also
based on their ancestry and descent.
 Systematics, focuses on analyzing the diversity of organisms in the context o their
natural relationships. It incorporates taxonomy and phylogenetics.
 Taxonomy is the science of describing, naming, and classifying species.
 Phylogenetics or phylogenetic systematics is the science that focuses on the
evolutionary history of a group of species.
 Phylogenetic Tree is an illustration or a diagram used to visually present the
SLIDE NO. evolutionary relationships or variability among groups and organisms.

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 SYSTEMATICS:
TRACING OUR LIFE’S HISTORY

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 CLADISTICS:
TRACING OUR LIFE’S HISTORY

 It is a common method used by taxonomists to create an evolutionary tree.

Cladistics relies on common ancestry as basis for establishing the classification on
how organisms descended from a common ancestor. The assumptions of cladistics
are:
• Groups of related species descended from a common ancestor;
• Branching patterns symbolizes relationships among groups, with new
evolutionary groups arising from a common ancestor; and
• characteristics change over time
 Ancestral Characteristics are traits inherited from the common ancestor of the
group.
 Derived Characteristics are features that are different from those present in the
group.
 Cladogram, depicts patterns of shared derived traits among groups of organisms
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 CLADISTICS:
TRACING OUR LIFE’S HISTORY

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 CLADISTICS:
TRACING OUR LIFE’S HISTORY

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