Class 9 Science Chapter 7 Diversity in Living Organisms Notes

9 Class Science Chapter 7 Diversity in Living Organisms Notes

Textbook	NCERT
Class	Class 9
Subject	Science
Chapter	Chapter 7
Chapter Name	Diversity in Living Organisms
Category	Class 9 Science Notes
Medium	English

Class 9 Science Chapter 7 Diversity in Living Organisms Notes. here we will be learn about Biodiversity , Nomenclature , Taxonomy , Things to keep in mind while writing names , Evolution , Classification , FIVE KINGDOM CLASSIFICATIONS , MONERA , PROTISTA , FUNGI , PLANTAE , ANIMALIA , Vertebrates etc.

Class 9 Science Chapter 7 Diversity in Living Organisms Notes

Chapter = 7
Diversity in Living Organisms

Topics in this Chapters :-

Biodiversity
Nomenclature
Taxonomy
Things to keep in mind while writing names
Evolution
Classification
FIVE KINGDOM CLASSIFICATIONS
- MONERA
- PROTISTA
- FUNGI
- PLANTAE
- ANIMALIA
Vertebrates

Biodiversity :-

Biodiversity means the variety of living organisms present in a particular region. There are about 20 lac organisms known on the earth which differ from one another in external form, internal structure, mode of nutrition, Habitat, etc.

Nomenclature :-

It is a system of assigning scientific names to the organisms. An organism can have different names in different languages. This creates confusion in naming organism.

A scientific name is needed which is same in all languages. Binomial nomenclature system given by Carolus Linnaeus is used naming different organisms.

Taxonomy :-

It is a branch of biology which deals with identification. nomenclature and classification of organisms. Carolus Linnaeus is called the father of taxonomy.

Things to keep in mind while writing names :-

Following are some (rules and norms) conventions to be followed in writing the scientific name of an organisms :-

The Name consist of two part :-

Genus
species.

Genus should be written first followed by the species.
First letter of the genus should be capital and that of the species should be in small letter.
When printed the scientific name should be written in italics and when written with hands genus and species should be underlined separately.

Example :- Homo sapiens for Human and Panthera tigris for Tiger.

Evolution :-

Evolution is a slow and continuous process during which early organism on earth emerged , adapted and diversified into various form.

Charles Darwin first described the idea of evolution in 1859 in his book ‘ The origin of species ‘.

Classification :-

The method of arranging organisms into groups or sets on the basis of similarities and differences in called classification.

Importance of Classification :-

It makes the study of wide variety of organisms easy and in systematic manner.
It helps to understand how the different organisms have evolved with time.
It forms a base for the study of other biological sciences , like biogeography.

Basis of Classification :-

There are certain features or properties used for the classification of living organisms which are known as characteristics . Organisms with same characteristics are placed in same groups.

Hierarchy of classification :-

Linnaeus proposed a classification system by arranging organisms into taxonomic groups at different levels according to the characteristics they have .

The groups or the levels from top to bottom are :-

Kingom → Phylum ( in Animal ) Division ( in plant ) → Class → Order → Family → Genus → Species .

Classification System :-

Two kingdom classification :- Carolus Linnaeus in 1758 classified the living organisms into two groups as plants and animals .

Five kingdom classificatoin :- R. Whittaker in 1959 further classified the organisms into five kingdoms as Fungi , Plantae , Animalia , Monera , Kingdom Protista .

Note :- Carl Woese in 1977 further divided kingdom Monera into archaebacteria ( or Archae ) and Eubacteria ( or Bacteria ).

Type of cellular structure :-

Prokaryotic cells :- These are primitive and incomplete cells without well – defined nucleus.

Eukaryotic cells :- These are advanced and complete cells with well defined nucleus.

Level of organisation :-

Cellular Level :- All living things are made up of cells . These are structural and functional unit of life.

Tissue level :- The cells organised to form tissue . A tissue is a group of cells which are similar in structure and perform a specific function.

Organ level :- Many tissues combine to form an organ , which performs a particular function.

Organ system level :- Group of organs work together to perform life activities . e.g. , the organs of digestive system work together to digest food.

Body Structure :-

Unicellular organisms :- These are organisms made up of single cell with all activities performed by the single cell.

Multicellular organisms :- These are organisms made up of large number of cells with different functions performed by different cells.

Mode of Nutrition ( obtaining food )

Autotrophs :- These are the organisms that make their own food by photosynthesis .

Heterotrophs :- These are the organisms which depend on other organisms for food .

FIVE KINGDOM CLASSIFICATIONS :-

MONERA
PROTISTA
FUNGI
PLANTAE
ANIMALIA

Kindom I : MONERA :-

Prokaryotic , unicellular , autotrophic or heterotrophic
May or may not have cell wall which is rigid and made up of peptidoglycan.

Examples :- Anabaena , Bacteria , Cyano – bacteria or Blue – green algae ( autotrophic ).

Kingdom II : PROTISTA :-

Eukaryotic , unicellular.
Can be autotrophic or heterotrophic.
May have cilia , flagella or pseudopodia for locomotion.

Examples :- Plants like unicellular algae , diatoms ; animals like protozoans ( Amoeba , Paramecium , Euglena ) ; fungi like slime molds and water moulds.

Kingdom III : FUNGI :-

Eukaryotic , cell wall is made up of chitin.
Mostly multicellular but sometimes unicellular ( yeast ).

Mode of nutrition :-

Mostly saprophytes :- These organisms use dead and decaying organic material for food.

Some parasitic :- These organisms live inside or outside the body of other living organism to have food and can be disease causing.

Symbiotic relation :- These are relations between two organisms in Which they live together for benefit of one or both . Lichens are a symbiotic relation between a fungi and cynobacteria / algae . Here fungi gets food from cyanobacteria and in return cyanobacteria gets water mineral and protection from fungi .

Examples :- Mushrooms ( Agaricus ) , green mould ( Penicillium ) , smut ( Aspergillus ) , yeast

Kingdom IV : PLANTAE :-

Eukaryotic , multicellular.
Some maybe heterotrophs also Autotrophs.
Cell wall is made up of cellulose and hemicellulose .

Kingdom Plantae further classified into 5 division based on following ( features ) basis

Differentiated body parts :- Body is differentiated into leaves stems , roots , flowers , etc.

Presence of vascular tissue :- There are two types of vascular tissues present in the plants :-

Xylem :- Helps in transport of water & Minerals.
Phloem :- Helps in transport of food .

Reproduction through seeds or spores :-

Phanerogam :- Plants with seeds are called phanerogam. They contains embryo with stored food and are multicellular.
Cryptogam :- Plants reproduce by spores , without flower and seeds . They contains only naked embryo .

Seeds are naked or covered ( fruit ) :-

Angiospermae :- These are plants with seeds inside the fruit and bears flowers.
Gymnospermae :- These are plants with naked seeds and do not bear flowers or fruit.

Division 1 :- Thallophyta

Basic and elementary plants with undifferentiated body parts .
Generally called algae.
No vascular tissue present.
Reproduce through spores.
Mainly found in water ( aquatic )

Example :- Ulva , Spirogyra , Ulothrix , Cladophora , Chara.

Division 2 :- Bryophyta

Body structure differentiated but not fully developed.
No vascular tissues present.
Reproduce through spores.
Found on both land and water therefore known as ‘ Amphibians of Plantae Kingdom.

Example :- Liverwort ( Marchantia , Riccia ) , Mosses ( Funaria ) , Hornwort ( Dendrocerous ).

Division 3 : Pteridophyta :-

Differentiated body structure – leaves , stems , roots , etc.
Vascular tissues present are incomplete.
Reproduce through spores.

Examples : Marsilea , fern , horsetails.

Division 4 : Gymnosperms :-

Differentiated body parts i.e. leaves , stem and root etc.
Vascular tissues present ( incomplete )
Naked seeds without fruits or flowers.
Perennial , evergreen and woody.

Examples :- Pines ( deodar ) , Cycas , Ginkgo .

Division 5 : Angiosperms :-

Also known as flower – bearing plants.
Later on flower becomes fruit after fertilistatoin.
Seeds are inside the fruit.
Plant Embryos in seeds have structure called cotyledons . They are also called seed leaves because in many plants they emerge and become green when they germinate.
Vascular Tissue present ( Complete )

Kingdom V : ANIMALIA :-

Basis of classification of Animalia kingdom :-

Symmetry :-

Bilateral symmetry :- It is when an organism can be divided into right and left equal halves , identical but mirror images , by a single vertical plane .
Radial symmetry :- It is when an organism is equally spaced around a central point , like spokes on a bicycle wheel .

Germ layers :- In embryonic stages there are different layers of cells called germ layer . The three different types of germ layer are :

Ectoderm :- It is the outermost layer which forms nail , hair , epidermis , etc.
Endoderm :- It is the innermost layer which forms stomach , colon , urinary , bladder , etc.
Mesoderm :- It is the middle layer between ectoderm and endoderm which forms bones , cartilage , etc.

So , according to the number of germ layers present inembryonic stage , animal could be :-

Diploblastic :- Organisms which are derived from two embryonic germ layers ( ecto and endo ).
Triploblastic :- Organisms which are derived from all the three embryonic germ layers.( ectoderm , mesoderm and endoderm )

Coelom :- Body cavity or coelom is important for proper functiong of various organs .

On the basis of presence or absence of coelom , organisms are divided into :-

Acoelomates :- These are the simple organisms having no body cavity . e.g. , Coelentrata , Platyhelminthes
Coelomates :- These are complex organisms having true cavity lined by mesoderm from all sides . e.g. , Annelida , Mollusca , Arthropoda etc.
Pseudo coelomate :- These are organisms having false coelom . They have pouches of mesoderm scattered between endoderm and ectoderm . e.g. , Nematoda

Notochord :- It is a long rod like structure , which runs along the body between nervous , tissue and gut and provides place muscle to attach for ease of movement.

Organisms could be :-

Without notochord – Non Chordate
with notochord – Protochordate
with notochord in initial embryonic stages and vertebral column in adult phase – Vertebrates

Phylum 1 : Porifera or Sponges :-

Cellular level of organization. ( They have porous body ).
Non – motile animals ( sessile )
Holes on body which led to a cannal system for circulation of water and food.
Hard outside layer called as skeletons.
Examples :- Sycon , Spongilla , Euplectelia

Phylum 2 : Coelenterata :-

Tissue level of organization
No coelom acoelomates )
Radial symmetry , diploblastic
Hollow gut
Can move from one place to another
Examples :- Hydra , sea anemone , jelly fish ( solitary ) , corals ( colonies )

Phylum 3 : Platyhelminthes :-

Also called flat worms
No coelom present
Bilateral symmetry , triploblastic
Free living or parasitic
Digestive cavity has one opening for both ingestion and egestion
Examples :- Planaria ( free living ) , liver fluke ( parasitic )

Pylum 4 : Nematoda :-

No true coelom ( Pseudocoelomate )
Triploblastic , bilateral symmetry
They are Parastic worm.
Male and female distinct from each other.
eg . Ascaris , Hookworm , Pinworm etc.

Phylum 5 : Annelida :-

Second largest phylum
Coelom present
Bilateral Symmetry , Triploblastic
The body is Metamarically Segmented ( segments specialized for different functions )
Water or land ( acquatic or Terristrial habitat )
Extensive organ differentiation.
Examples : Earthworm , Leech , Nereis

Phylum 6 : Arthropoda :- ( Jointed legs )

Largest phylum ( conist of 80 % of species )
Generally known as insects.
True Coelom present , Body is divided into 3 Region – head , thorax & Abdomen.
Bilateral symmetry , triploblastic.
Tough exo – skeleton made up of chitin.
Jointed appendages like feet , antenna
Examples :- Prawn , scorpion , cockroach , housefly , butterfly , spider

Phylum 7 : Mollusca

Coelom present
Triploblastic , bilateral symmetry
soft bodies , sometimes covered with hard shell
Generally not segmented
Muscular foot for movement
Kidney like organ for excretion
Examples :- Chiton , octopus , pila , unio

Phylum 8 : Echinodermata ( Spiny skin )

Spiny skin , marine
No notochord
Coelom present , triploblastic , bilateral symmetry or radial symmetry
Endoskeleton of calcium carbonate
Water vascular system for locomotion
Examples :- Antedon , sea cucumber , star fish , echinus

Phylum 9 : Hemichordata

Small group of marine animals
Cylindrical , bilateral symmetry , triploblastic
Coelom present
Gills for respiration
Examples :- Balanoglossus

Phylum 10 : Chordata

Bilateral symmetry , triploblastic
Coelom present with organ system level of organisation
Notochord present
Gills present at some phase of life
Dorsal nerve chord present
Post anal tail present at some stage of life , for example , in humans in embryonic stages .

Sub – divided into two :-

Protochordata :-

Notochord at some stage of life.
Marine
Examples :- Herdmania , amphioxus

Vertebrata :-

Notochord converted to vertebral column
Organs like kidney for excretion and osmoregulation
Paired appendages ( eg.fins or limbs )
2 , 3 , 4 chambered heart examples :- Humans ( 4 – chambered ) , frog ( 3 chambered ) , fishes ( 2 – chambered )

Vertebrates :-

Vertebrates are divided into five classes namely Pisces , Amphibia , Reptilia , Aves and Mammalia .

Warm blooded organisms :- These are organisms which maintain same body temperature irrespective of outside temperature .

Example :- Humans beings . Human’s body temperature is approximately 37 ° c.

Cold blooded organisms :- These are organisms which change their body temperature as per surrounding temperature .

Example : Frog.

Pisces ( Fishes ) :-

Their skin is covered with scales or plates.
They respire using gills.
They have streamlined body and fins which help them to move in water.
They are cold blooded and their heart has only two chambers.
They lay eggs from which the young ones hatch out ( oviparous ) but some may be viviparous .

Fishes with cartilage skeleton called cartilaginous fishes.

Example :- Shark , sting Ray .

Fishes with bony skeleton are called bony fishes .

Example – Rohu

Amphibia ( Amphibians ) :-

They are found in land and water. They need water for completion of life cycle.
They do not have scales but have mucous glands on their skin.
They are cold blooded and the heart is three chambered.
Respiration is through gills or lungs.
They lay eggs in water . Frogs , Toads , Salamanders etc.

Reptilia ( Reptiles ) :-

They have scales as exoskeleton and breathe through lungs.
They are cold blooded.
Most of them have three chambered heart but crocodiles have four chambered heart.
They lay eggs with hard covering , on Land .
Example :- Snakes , Turtles , Lizards , Crocodiles etc.

Aves ( Birds ) :-

They are warm blooded animals.
They have four chambered heart.
They breathe through lungs. Have hollow Bones ( Pneumatic bones ) that help in flying.
They have an outer covering of feathers ( Exoskeleton )
Their two fore limbs are modified into wings for flying. They lay eggs.
Example :- Crow , Sparrow , Pigeon , Duck , Stork , Ostrich etc.

Mammalia ( Mammals ) :-

They are warm blooded animals.
They have four chambered heart.
They have mammary glands for production of milk to nourish their young ones.
The skin has hairs and sweat glands. Most of them give birth to their young ones.
Some of them lay eggs ( like Platypus and Echidna ).
Example :- Cat , Rat , Dog , Lion , Tiger , Whale , Bat , Humans etc.