9th Class Science Notes in English chapter 7 Diversity in Living Organism

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9th Class Science Notes in English chapter 7 Diversity in Living Organism


CBSE Revision Notes for CBSE Class 09 Science Diversity in Living Organisms: Diversity of plants and animals - basic issues in scientific naming, basis of classification. Hierarchy of categories / groups, Major groups of plants (salient features) (Bacteria, Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms). Major groups of animals (salient features) (Non-chordates upto phyla and chordates upto classes).


Class 9th Science chapter 7 Diversity in Living Organism Notes in English


📚 Chapter - 7 📚
👉 Diversity in Living Organism 👈


✳️Diversity:-


🔹 Diversity is the presence of different organisms in the same ecosystem or geographical location.

🔹 Diversity gives a chance for a more balanced ecosystem.


✳️Biodiversity:-


🔹 The variety of animals and plants living in a given geographical area is called biodiversity of that geographical area.


✳️Taxonomy:-


🔹 It is a branch of biology which deals with identification, nomenclature, and classification of organisms.

🔹 Carolus Linnaeus is called the father of Taxonomy )

✳️Classification:-


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


✳️Evolution:-


🔹 Evolution is the slow process by which the organisms change according to the needs to survive the environment around them.


✳️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 helps to understand the relationships between different groups of organisms.

🔹 It forms a base for the study of other biological sciences, like biogeography.


✳️Basis of classification:-


🔹 There are the 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.


✳️Classification System:-


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


👉 Type of cellular organization:-


🔹 a) Prokaryotic cells: These are primitive incomplete cells without well-defined nucleus. 

🔹 b) Eukaryotic cells: These are advanced and complete and cells with well defined nucleus.


👉 Body organization:-


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

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


👉 Mode of obtaining food:-


🔹 a) Autotrophs: These are the organisms that make their own food by photosynthesis. 

🔹 b) Heterotrophs: These are the organisms which depend on other organisms for food.


✳️Nomenclature:- 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.


✳️Following are some conventions in writing the scientific names:-


🔹 1. Genus should be written followed by the species. 

🔹 2. First letter of the genus should be capital and that of the species should be in small letter. 

🔹 3. When printed the name should be written in italics and when written with hands genus and species should underlined separately. 

🔹 Example: Homo sapiens for humans, 

                       Panthera tigris for tiger


✳️Five kingdom classification:-


🔹 H. Whittaker in 1959 classified the organisms into five kingdoms as (i) Kingdom Monera, (ii) Kingdom Protista, (iii) Kingdom Fungi, (iv) Kingdom Plantae and (v) Kingdom Animalia.


👉 Kingdom Monera:-


🔹 (i) Type: Unicellular Prokaryotic 

🔹 (ii) Mode of nutrition: Autotrophic or heterotrophic 

🔹 (iii) Body: Lack well-defined nucleus and cell organelles 

🔹 (iv) Examples: Anabaena and Bacteria, Blue-green algae

9th Class Science Notes in English chapter 7 Diversity in Living Organism

👉 Kingdom Protista:-


🔹 (i) Type: Unicellular Eukaryotic 

🔹 (ii) Mode of nutrition: Autotrophic or Heterotrophic 

🔹 (iii) Body: Some organisms use pseudopodia or cilia or flagella for movement 

🔹 (iv) Examples: Amoeba, Paramecium, Euglena

9th Class Science Notes in English chapter 7 Diversity in Living Organism

👉 Kingdom Fungi:-


🔹 (i) Type: Multicellular Non-green Eukaryotic 

🔹 (ii) Mode of nutrition: Saprophytic or Parasitic Sometimes symbiotic 

🔹 (iii) Body: Fungus is made up of long filaments called hyphae. The network of hyphae is mycelium. 

🔹 (iv) Examples: Yeast, Pencilium, Agaricus, Mushrooms moulds 

9th Class Science Notes in English chapter 7 Diversity in Living Organism

👉 Kingdom Plantae:-


🔹 (i) Type: Multicellular Eukaryotic 

🔹 (ii) Mode of nutrition: Autotrophic 

🔹 (iii) Body: Exhibits high level of tissue differentiation and have specialized body organs.

🔹 (iv) Examples: Trees, Plants, Shrubs 


9th Class Science Notes in English chapter 7 Diversity in Living Organism

👉 Kingdom Animalia:-


🔹 (i) Type: Multicellular Eukaryotic 

🔹 (ii) Mode of nutrition: Heterotrophic 

🔹 (iii) Body: Exhibits high level of tissue differentiation and have specialized body organs. They have well developed nervous system. 

🔹 (iv) Examples: Fish, Insects, Animals, Humans, Birds

9th Class Science Notes in English chapter 7 Diversity in Living Organism


✳️Some Important Points:-


👉 Phanerogam:- Plants with seeds are called phanerogam. They contains embryo with stored food and are multicellular.


👉 Cryotogam:- Plants with spores are called cryptogam. They contains only naked embryo and are generally unicellular


👉 Gymnosperms:- These are plants with naked seeds and do not bear flowers. These types of plants are perennial, evergreen and woody. Example- Pinus, Cycus etc. 


👉 Angiosperms:- These are plants with seeds inside the fruit and bears flowers. Embryos in seed have structure called cotyledons. 


🔹 Angiosperms are further divided on the basis of number of cotyledons into two parts i.e., Monocots and Dicots.

9th Class Science Notes in English chapter 7 Diversity in Living Organism


👉 Arthropoda:- Arthropoda is the largest phylum which consist of 80% species. Scorpio, Cockroach, Housfly, Butterfly, Spider etc are example of arthropoda species.


👉 Annelida:- Annelida is second largest phylum. Earthworm, leech nereis arė example of annelida species. 


👉 Taxonomy:- Taxonomy is a branch of biology which deals with identification, nomenclature and classification of organisms. 


👉 Carolus Lannaeus:- Carolus Lannaeus is called the father of Taxonomy. 


✳️Vertebrata:-


🔹 Vertebrata:- Vertebrata are those animals which have have a chord like structure (vertebral column present in their body). 


🔹 Vertebrates are divided into five classes namely (i) Pisces, (ii) Amphibia, (iii) Reptilia, (iv) Aves and (v) Mammalia.


👉 Pisces (Fishes)


🔹 They are fishes living in water. 

🔹 Their skin is covered with scales or plates. 

🔹 They respire using gills. 

🔹 They are cold blooded and their heart has only two chambers. 

🔹 They lay eggs from which the young ones hatch out 

🔹 Example: Sharks, Rohu etc. 

9th Class Science Notes in English chapter 7 Diversity in Living Organism
9th Class Science Notes in English chapter 7 Diversity in Living Organism

👉 Amphibia (Amphibians)


🔹 They are found in land and water. 

🔹 They are cold blooded and the heart is three chambered. 

🔹 Respiration is through gills or lungs. 

🔹 They lay eggs in water. 

🔹 Example: Frogs, Toads, Salamanders etc. 

9th Class Science Notes in English chapter 7 Diversity in Living Organism


👉 Reptilia (Reptiles)


🔹 They have scales 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 in water. 

🔹 Example : Snakes, Turtles, Lizards, Crocodiles etc.

9th Class Science Notes in English chapter 7 Diversity in Living Organism


👉 Aves (Birds)


🔹 They are warm blooded animals. 

🔹 They have four chambered heart. 

🔹 They breathe through lungs. 

🔹 They have an outer covering of feathers. 

🔹 Their two fore limbs are modified into wings for flying. 

🔹 They lay eggs. 

🔹 Example: Crow, Sparrow, Pigeon, Duck, Stork, Ostrich etc.

9th Class Science Notes in English chapter 7 Diversity in Living Organism


👉 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. 

9th Class Science Notes in English chapter 7 Diversity in Living Organism