9th Grade

Diversity in
Living
Organisms
Exploring the richness of life on Earth

Pravar Singh Chaudhary Class 9-B

Diversity In Living Organisms
1. Diversity in living organisms refers to the wide range of species that
exist in the natural world, encompassing various forms of life such
as microorganisms, plants, animals, and fungi.
2. Studying diversity is essential as it helps understand the variety of
life forms on Earth. It teaches about the interconnectedness of
organisms within ecosystems.
3. Recognizing diversity fosters conservation awareness and promotes
environmental stewardship.
4. Understanding diverse species aids in agricultural practices and
medical research.
5. Appreciating biodiversity enriches cultural connections to nature
and supports sustainable development efforts.Instructions for use.
Taxonomy
Taxonomy is defined as the science of classification of living
organisms based on similarities and differences in their
characteristics. It involves categorizing organisms into groups or taxa
to organize and understand the vast diversity of life on Earth.

Carolus Linnaeus is recognized for his significant contributions to the

classification of living organisms. His major contributions include:
1. Development of Binomial Nomenclature
2. Establishment of Hierarchical Classification
3. Publication of "Systema Naturae": Linnaeus published "Systema
Naturae" in 1735, which laid the foundation for modern taxonomy
The Hierarchy of ClassificationGroups :-
Biologists, such as Ernst Haeckel (1894),
Robert Whittaker (1969) and Carl Woese
(1977) have tried to classify all living
organisms into broad categories, called
kingdoms. The classification Whittaker
proposed has five kingdoms: Monera,
Protista, Fungi, Plantae and Animalia,
and is widely used.
 Further classification is done by naming the sub-
groups at various levels as given in the following
scheme:

6.Phylum/
Division
4.Order 5.Class

3.Family 2.Genus

1. Species
The important characteristics of the five kingdoms of
Whittaker are as follows:

● Monera

Monera are defined as a group of unicellular organisms characterized by

prokaryotic cell structure. They lack a nucleus and membrane-bound organelles.
Monera include bacteria and blue-green algae (cyanobacteria). They play crucial
roles in nutrient cycling, decomposition, and symbiotic relationships.
● Protista

Protista are defined as a diverse group of mostly unicellular eukaryotic

organisms. They exhibit various modes of nutrition and locomotion. Protists
include protozoans, algae, and slime molds, inhabiting diverse aquatic and
terrestrial environments. They play vital ecological roles as primary producers
and consumers in ecosystems.
● Plantae

Plantae are defined as a kingdom of multicellular, eukaryotic organisms

characterized by autotrophic nutrition. They possess cell walls made of cellulose
and chloroplasts for photosynthesis. Plantae encompass a wide variety of
species, including mosses, ferns, gymnosperms, and angiosperms, contributing
to oxygen production, food webs, and ecosystem stability.
● Thallopytha

Plants that do not have well-differentiated body design fall in this group. The
plants in this group are commonly called algae. These plants 2020-21 86 SCIENCE
are predominantly aquatic. Examples are Spirogyra, Ulothrix, Cladophora, Ulva
and Chara.
● BRYOPHYTA

These are called the amphibians of the plant kingdom. The plant body is
commonly differentiated to form stem and leaf-like structures. However, there is
no specialised tissue for the conduction of water and other substances from one
part of the plant body to another. Examples are moss (Funaria) and Marchantia
● PTERIDOPHYTA

In this group, the plant body is differentiated into roots, stem and leaves and has
specialised tissue for the conduction of water and other substances from one
part of the plant body to another. Some examples are Marsilea, ferns and horse-
tails
● ANGIOSPERMS

These are also called flowering plants. The seeds develop inside an ovary which is
modified to become a fruit. Plant embryos in seeds have structures called
cotyledons. Cotyledons are called ‘seed leaves’ because in many instances they
emerge and become green when the seed germinates. The angiosperms are
divided into two groups on the basis of the number of cotyledons present in the
seed. Plants with seeds having a single cotyledon are called monocotyledonous
or monocots. Plants with seeds having two cotyledons are called dicots.
● GYMNOSPERMS

This term is derived from two Greek words: gymno– means naked and sperma–
means seed. The plants of this group bear naked seeds and are usually perennial,
evergreen and woody. Examples are pines and deodar
● Fungi

These are heterotrophic eukaryotic organisms. Some of them use decaying

organic material as food and are therefore called saprotrophs. Others require a
living protoplasm of a host organism for food. They are called parasites. Many of
them have the capacity to become multicellular organisms at certain stages in
their lives. They have cellwalls made of a tough complex sugar called chitin.
Examples are yeasts, molds and mushrooms.
● Animalia

Animalia is defined as a kingdom comprising multicellular, eukaryotic

organisms characterized by heterotrophic nutrition. They lack cell walls and
typically exhibit mobility at some stage of their life cycle. Animalia encompasses
a wide diversity of species, including invertebrates and vertebrates, playing
various ecological roles in ecosystems.
● PORIFERA

The word Porifera means organisms with holes. These are non-motile animals
attached to some solid support. There are holes or ‘pores’, all over the body. These
lead to a canal system that helps in circulating water throughout the body to
bring in food and oxygen. These animals are covered with a hard outside layer or
skeleton. The body design involves very minimal differentiation and division into
tissues. They are commonly called sponges, and are mainly found in marine
habitats.
● COELENTERATA (CNIDARIA)

These are animals living in water. They show more body design differentiation.
There is a cavity in the body. The body is made of two layers of cells: one makes
up cells on the outside of the body, and the other makes the inner lining of the
body. Some of these species live in colonies (corals), while others have a solitary
like–span (Hydra). Jellyfish and sea anemones are common examples.
● PLATYHELMINTHES

The body of animals in this group is far more complexly designed than in the two
other groups we have considered so far. The body is bilaterally symmetrical,
meaning that the left and the right halves of the body have the same design.
There are three layers of cells from which differentiated tissues can be made,
which is why such animals are called triploblastic. This allows outside and inside
body linings as well as some organs to be made. There is thus some

degree of tissue formation. However, there is no true internal body

cavity or coelom, in which well developed organs can be

accommodated. The body is flattened dorsoventrally

(meaning from top to bottom), which is why these animals

are called flatworms. They are either free-living or parasitic.

Some examples are free-living animals like planarians, or parasitic

animals like liverflukes.

● NEMATODA

The nematode body is also bilaterally symmetrical and triploblastic. However, the
body is cylindrical rather than flattened. There are tissues, but no real organs,
although a sort of body cavity or a pseudocoelom, is present. These are very
familiar as parasitic worms causing diseases, such as the worms causing
elephantiasis (filarial worms) or the worms in the intestines (roundworm or
pinworms)
● ANNELIDA

Annelid animals are also bilaterally symmetrical and triploblastic, but in

addition they have a true body cavity. This allows true organs to be packaged in
the body structure. There is, thus, extensive organ differentiation. This
differentiation occurs in a segmental fashion, with the segments lined up one
after the other from head to tail. These animals are found in a variety of habitats–
fresh water, marine water as well as land. Earthworms and leeches are familiar
examples.
● ARTHROPODA

This is probably the largest group of

animals. These animals are bilaterally

symmetrical and segmented. There is

an open circulatory system, and so the

blood does not flow in welldefined blood

vessels. The coelomic cavity is

blood-filled. They have jointed legs (the

word ‘arthropod’ means ‘jointed legs’).

Some familiar examples are prawns,

butterflies, houseflies, spiders, scorpions and crabs.

● MOLLUSCA

In the animals of this group, there is bilateral symmetry. The coelomic cavity is
reduced. There is little segmentation. They have an open circulatory system and
kidney-like organs for excretion. There is a foot that is used for moving around.
Examples are snails and mussels
● PROTOCHORDATA

These animals are bilaterally symmetrical,

triploblastic and have a coelom. In addition,

they show a new feature of body design, namely

a notochord, at least at some stages during their

lives. The notochord is a long rod-like support

structure (chord=string) that runs along the back

of the animal separating the nervous tissue from

the gut. It provides a place for muscles to attach

for ease of movement. Protochordates may not have

a proper notochord present at all stages in their lives or for the entire length of
the animal. Protochordates are marine animals. Examples are Balanoglossus,
Herdmania and Amphioxus.
● VERTEBRATA
These animals have a true vertebral column and internal
skeleton, allowing a completely different distribution of muscle
attachment points to be used for movement. Vertebrates are
bilaterally symmetrical, triploblastic, coelomic and segmented,
with complex differentiation of body tissues and organs. All
chordates possess the following features:
(i) have a notochord
(ii) have a dorsal nerve cord
(iii) are triploblastic
(iv) have paired gill pouches
(v) are coelomate.
● CYCLOSTOMATA
Cyclostomes are jawless
vertebrates. They are
characterised by having
an elongated eel-like
body, circular mouth , slimy skin and are
scaleless. They are ectoparasites or borers of
other vertebrates. Petromyzon (Lamprey) and
Myxine (Hagfish) are examples.
● PISCES

These are fish. They are exclusively aquatic animals. Their skin is covered with
scales/ plates. They obtain oxygen dissolved in water by using gills. The body is
streamlined, and a muscular tail is used for movement. They are cold-blooded
and their hearts have only two chambers, unlike the four that humans have. They
lay eggs. We can think of many kinds of fish, some with skeletons made entirely
of cartilage, such as sharks, and some with a skeleton made of both bone and
cartilage, such as tuna or rohu.
● AMPHIBIA

These animals differ from the fish in the lack of scales, in having mucus glands
in the skin, and a three-chambered heart. Respiration is through either gills or
lungs. They lay eggs. These animals are found both in water and on land. Frogs,
toads and salamanders are some examples.
● REPTILIA

These animals are cold-blooded, have scales and breathe through lungs. While
most of them have a three-chambered heart, crocodiles have four heart
chambers. They lay eggs with tough coverings and do not need to lay their eggs in
water, unlike amphibians. Snakes, turtles, lizards and crocodiles fall in this
category.
● AVES

These are warm-blooded animals and have a four-chambered heart. They lay
eggs. There is an outside covering of feathers, and two forelimbs are modified for
flight. They breathe through lungs. All birds fall in this category.
● Mammals

Mammals are warm-blooded animals with

four-chambered hearts. They have mammary

glands for the production of milk to nourish

their young. Their skin has hairs as well as

sweat and oil glands. Most mammals familiar

to us produce live young ones. However, a f

ew of them, like the platypus and the echidna

lay eggs, and some, like kangaroos give birth

to very poorly developed young ones.

● Nomenclature

Nomenclature refers to the system of assigning names to living organisms

based on standardized conventions. It involves the use of binomial nomenclature,

where each organism is given a unique two-part Latin name consisting of its genus

and species. This naming system, introduced by Carl Linnaeus, aids in clear

communication and organization within the scientific community.

Nomenclature provides a universal language for identifying and classifying

organisms, facilitating the study of biodiversity and evolution.

It plays a crucial role in taxonomy,

the science of classifying and categorizing living organisms.

 Importance of Biodiversity

Ecological Economic Ethical and

importance importance cultural
of of importance
biodiversity biodiversity of
biodiversity
“Nature's diversity is not just a matter of
numbers; it is a web of interactions, a
richness of relationships that sustains life
on Earth."

—Davis Suzuki

THANKS FOR YOUR

ATTENTION!!!!