Class 9 Science Chapter 7 Diversity in Living Organisms Notes

9 Class Science Chapter 7 Diversity in Living Organisms Notes

TextbookNCERT
ClassClass 9
SubjectScience
Chapter Chapter 7
Chapter NameDiversity in Living Organisms
CategoryClass 9 Science Notes
MediumEnglish

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

πŸ“š Chapter = 7 πŸ“š
πŸ’  Diversity in Living Organisms πŸ’ 

❇️ 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 :-

πŸ”Ή 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 :-

πŸ”Ή 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. 

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

❇️ Taxonomy :-

πŸ”Ή 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 :-

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

πŸ”Ή 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.

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

❇️ Evolution :-

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

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

❇️ Classification :-

πŸ”Ή 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 :-

πŸ”ΉThere 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 :-

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

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

  • Kingom β†’ Phylum ( in Animal ) Division ( in plant ) β†’ Class β†’ Order β†’ Family β†’ Genus β†’ Species . 

❇️ Classification System :-

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

πŸ”Ά 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 :-

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

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

❇️ Level of organisation :-

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

πŸ”Ά 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.

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

πŸ”Ά 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 :-

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

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

❇️ Mode of Nutrition ( obtaining food ) 

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

πŸ”Ά 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. 

πŸ”Ή 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.

πŸ”Ή 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 ).

πŸ”Ή Mode of nutrition :- 

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

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

πŸ”Ά 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 . 

πŸ”Ή 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 . 

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

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

πŸ”Ά 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 . 

πŸ”Ά 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 .

πŸ”Ά 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.

πŸ”Ά 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 ) 

πŸ”Ή Example :- Ulva , Spirogyra , Ulothrix , Cladophora , Chara.

πŸ”Ά 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.

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

πŸ”Ά Division 3 : Pteridophyta :-

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

πŸ”Ή Examples : Marsilea , fern , horsetails. 

πŸ”Ά 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. 

πŸ”Ή Examples :- Pines ( deodar ) , Cycas , Ginkgo .

πŸ”Ά 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 :-

πŸ”Ή Basis of classification of Animalia kingdom :-

πŸ”Ά 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 . 

πŸ”Ά 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.

πŸ”Ή 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 ) 

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

πŸ”Ή 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 

πŸ”Ά 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.

πŸ”Ή 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 . 

πŸ”Ή Sub – divided into two :-

πŸ”Ά Protochordata :-

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

πŸ”Ά 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 :-

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

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

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

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

πŸ”Ή 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 . 

πŸ”Ή Fishes with cartilage skeleton called cartilaginous fishes.

Example :- Shark , sting Ray . 

πŸ”Ή 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 ).Β 
  • Example :- Cat , Rat , Dog , Lion , Tiger , Whale , Bat , Humans etc.
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