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CLASS 9th

DIVERSITY IN LIVING ORGANISMS

BIOLOGY

CLASSIFICATION: - Classification of organisms may be defined as a system of
arrangement of organisms into different groups and sub-groups on the basis of their
similarities, differences and relationship
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It has the following
advantages
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Classification makes the study of a wide variety of organisms convenient and
easy
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It is not possible for man to know about all the organisms but the study of a
few representatives from each taxonomic group gives a general idea of all life
forms at a glance
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Classification also reveals the interrelationship among different gr4oups of
organisms
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Correct identification of an organism and its placement in a definite taxonomic
group is the basic requirement of various branches of biological sciences
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BASIS OF CLASSIFICATION:Classification can be done on the following basis
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Cells are prokaryotic or eukaryotic
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In case of prokaryotic cells the nuclei and other organelles
are not clearly demarcated
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2
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Many organisms are unicellular, i
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made
up of only one cell, e
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Amoeba
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e
...
g
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In case of multicellular
organisms the different groups of cells carry out specialized functions
3
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Green plants
perform photosynthesis an synthesis their own food
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They get food from outside
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Organization of different body parts
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For example, plants possess stem, root and
leaves
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The characteristic based on body design used for classification of
plants is quite different when used for classifying animals
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He proposed five kingdoms:
1
...
Protista, 3
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Plantae and 5
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Monera: - these organisms do not have a defined nucleus or organelles, nor do any
of them show multi-cellullar body designs
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Some of organisms of this group are either autotrophic or
heterotrophic
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Protista:- This group includes many kinds of unicellular eukaryotic organisms
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Their mode of
nutrition can be autotrophic or heterotrophic
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CLASS 9th

DIVERSITY IN LIVING ORGANISMS

BIOLOGY

Fungi:- these are heterotrophic eukaryotic organisms
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They have cell-walls made of chitin
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Plantae:- these are multi-cellular eukaryotes with cell walls
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All plants are included in this group
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They are heterotrophs
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It involves the principals governed by set rules formulated by internationals bodies
so that a particular organism or taxon is known by its specific name throughout the
world
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For
example, the scientific binomial name of human species is Homo sapiens, where first
name Homo is generic and the second name sapiens is a specific
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Since this system of naming
organisms gives two names to an organism, it is known as a binomial
nomenclature
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In classification, the organisms that closely resemble one another are placed in a
group
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The larger groups are again placed in still larger grouping levels or
ranks in classification are known as categories
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There are seven major categories:
1
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Genus
3
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Order
5
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Phylum (for animals)/division (for plants)
7
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1
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Species is the lowest category regarded as basic unit classification
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2
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A genus is a group of closely resembling species having a common
ancestry
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3
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A family represents a larger group of closely related genera
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4
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An order is a group of closely related families
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Class
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6
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Phylum (in case of animals) or Division (in case of plants) is
a group of related classes
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Kingdom
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It is
group of phyla (in case of animals) or divisions (in case of plants)
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And were revised in 9th and 20th century
through international code of Botinical Nomenclature (ICBN) and international code
of Zoological nomenclature (ICZN)
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Each organisms has a distinct scientific name having a words, generic and
scientific
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The generic and specific words should not have less then three letters or more
than 12(twelve) letters
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The generic name is written first
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Is first letter is always
capital
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The specific word is written after the generic name, It starts with small letter
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The name of the discoverer is appended to the two-word scientific name either
In full or abbreviate form e
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, mangifera indic
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6
...

7
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KINGDOM PLANTAE:Characteristics features of kingdom plantae
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ii) They are multicellular
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iv) They store carbohydrates such as starch
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vi) The organisms feed by photosynthesis
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e crypotogamae and phanerogamae
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The flower/seed are
absent and hence these are considered to have hidden reproductive organs
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1)
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This kind of undifferentiated body is called thallus, hence the name
thallophytes
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(1) The plant body is thalloid i
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, cannot be differentiated into stem, root and
leaves
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(3) The reproductive organs are single called and there is no embryo formation
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Some 20,000species of algae
are known
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They are generally chorophyllous thallophytes in which vascular tissues are
absent
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The plant body is thalloid i
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, cannot be differentiated into root, stem and
leaves
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They are found in fresh water resources as well as in sea water
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They are autotrophic because of the presence of chlorophyll in leaves
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5
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The outer layer is made of pectin and inner
layer is made cellulose
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They may be unicellular as well as multicellular
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A few members such as chlamydomonas are motile
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They reproduce by vegetative, asexual as well as sexual methods
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Example : oedogonium, Chara, Sargassum, Ectocarpus, Chlamydomonas, Ulothrix
etc
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They show the following
characteristics :
1
...

2
...

3
...

4
...

5
...

6
...

7
...

8
...

9
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The
higher forms lack distinct sex organs
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(C) LICHENS : They represent a symbiotic association of a fungus and a alga in
which two organisms are so closely associated with each other as to form a single
plant
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The commonly grow on leaves, tree
trunks, old logs, soils and rocks
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In these plants the algal part prepares the food and the fungal part shows
reproduction
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2)
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They have over 25,000 species
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They lice in damp and sandy habitates hence they are called amphibians of
the plant kingdom
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2
...

3
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They may be
unicellular or multicellular
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The reproduction takes place by vegetative or sexual methods
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The vegetative reproduction is quite common through fragmentation tubes,
gemmae, buds, adventitions branches etc
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They show distinct alternation of generation
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(iii)
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The important characteristics are
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The plant body is differentiated into roots, stem, and leaves
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The dominant phase or plant body is a sporophyte
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They are seedless vascular plants and hence called vascular cryptogams
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The gymetophyte is small or inconspious
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The sex organs are multicellular
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The fertilization requires water medium results in the formation of zygote
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They show distinct alternation of generation
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PHANEROGAMAE: - They are seed bearing plants
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A well developed vascular system is presents in
phanerogames
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On the basis of fruit formation, they are classified into two subdivisions
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GYMNOSPERME:- the term is made from two Greek words : gymo – means
naked and sperme means seed
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It has nearly 650 living species
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They have well developed vascular tissues but lack vessels
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e
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2
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There is formation of pollen tube
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The zygote develops into an embryo
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Since the ovules are not covered by a cattel there is no fruit formation
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Example : Cycas, Pinus and Emphedra etc
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ANGIOSPERMAE:- The word is made from two Greek words: anger means
covered and sperma means seed
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These are also called flowering plants
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The general
characteristics are
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They are usually terrestrial plants
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2
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They may be annual, biennial or
perennial
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A well developed vascular system is present in them
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4
...

5
...

6
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Example : Brassica campestris (Mustard), Pisum santivum (pea) etc
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i
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the
veins on their leave are parallel to each other
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CLASS 9th

DIVERSITY IN LIVING ORGANISMS

BIOLOGY

Example : Palms, Bamboos, Sugar – can, rice etc
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Dicot:- the seeds of dicot have two cotyledons
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Their vascular bundles are arranged in a ring
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KINGDOM ANIMALAE
Characteristics features of kingdom Animalae are:I
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II
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III
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IV
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V
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VI
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Basis of animal classification:- They are many features used for distinguishing
broad categories of animals
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Organization
Animals are multicellular
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For example, animals such as sponges are
aggregate of cells
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Human beings have
organs and systems for performing body functions and are at the organ-system level
of organization
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Sponges
are symmetrical
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Body Cavity
Body cavity or coelom is a cavity between the body wall and the food canal
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The body cavity of
roundworms is not true and is known as Pseudocoelom
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Sponges and Cnidaria do not have mesoderm in their embryos and are
called diploblastic
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Notochord
The notochord is a stiff rod running along the body, close to the dorsal
surface
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All chordates possess
a notochord at some stage of their development
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CLASS 9th

DIVERSITY IN LIVING ORGANISMS

BIOLOGY

ANIMALS

Tissue

Cellular
Porifera

Codenterata

Annelida

Plathyhelminthes

Arthropoda

Nematoda

Coelomate

Mollusca

Echinodermate

Protochordata

Henichrodata

Chordata

Vertebrata

Pisces
Amphibia
Reptilia
Aves
Mammalia
(1) PORIFERA:The word means organisms with hopes
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They have holes all over the body
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They are commonly called sponges and are
mainly found in marine habitats
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(2) COELENTERATA:These are aquatic animals
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The body is made of two layer of cells;
one makes up cells on the outside and the other makes the inner living body of the
body
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Example: hydra, Jellyfish
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The body is
bilaterally symmetrical
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There are three layers of cells in them and thus are called triploblastic
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Reproduction is
mostly sexual
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(4) NEMATODA:The organisms belonging to this group are mostly parasites having selender,
elongated bodies
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There body is bilaterally symmetrical and
triploblastic
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Example: Ascaris,
Lumbricoides
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The annelids are worms with body
appearing as if made up of series of rings
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There is extensive organ differentiation
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Each
segment posseses a similar pattern of organs
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Example: Earthworms, leaches
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Thus,
arthopropoda means jointed legs
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They
metamerically segmented
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The coelomic
cavity is blood-filled
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Sexes are usually separate
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(7)
Mollusca:- the mollusca are animals with a coelomate triploblastic
body
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They have an open circulatory system and kidney
like organs for excretion
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They a muscular
foot to move
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Example: Snails, Mussels
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These are spiny skilled organisms
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They are triploblastic and have a coelomic cavity
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Sexes are separate
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(9) PROTOCHORDATA:- these are bilaterally symmetrical, triploblastic coelomate
animals
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These
are marine animals they have a closed blood system, they have a post-anal tail
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(10) VERTEBRATA:- these animals have a true vertebral column and internal
skelton vertebrates are bilaterally symmetrical, triploblastic, Coelomic and
segmented, with complex differentiated of body tissues and organs
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PISCES:- These are fish and live exclusively in water
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They use oxygen dissolved in water by gills
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They lay eggs
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Example: sharks, Tuna, Rohu etc
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AMPHIBIANS:-Amphibians means ‘Amphi’ ‘double’ and bias ‘life’
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Most amphibians lay their eggs in
water
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Example: Frogs, Toads and salamanders
etc
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REPTILES:- these animals can lively solely on land and are very less dependent
on water
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These
have three chambered heart (except crocodiles)
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Their skin is water proof and is covered with waterproof horny
scales
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(4)
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These are warm-blooded and have a four chambered heart
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Birds are distinguished because their bodies are covered with feathers, and
two forelimbs modified for flight
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Examples: Cuckoo,
crow, Sparrow etc
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MAMMALIA:- Mammals are warm-blooded animals with four-chambered hearts
...
Their
skin has hairs as well as sweet and oil glands
...
Sexes are separate
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