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.
