Class 9 Diversity in Living Organisms Notes

Notes Important Questions

Diversity in Living Organisms Notes

The hierarchy of classification groups:-

• Kingdom
  Phylum (for animals) / Division (for plants)
  • Class
    • Order
      • Family
        • Genus
          • Species

There are five types of kingdoms:-

Monera:-

• They are unicellular prokaryotes.
• Some of them have cell wall while some do not.
• The mode of nutrition in some of them is autotrophic and in some of them heterotrophic.
• For example:- Bacteria, blue green algae (cyanobacteria) and mycoplasma etc.

Protista:-

• These are unicellular eukaryotes.
• Some of them have hair like cilia or whip like flagella for moving around.
• They can be heterotrophic or autotrophic.
• For example:- Unicellular algae, diatoms and Protozoans (paramecium, amoeba, euglena).

Fungi:-

• These are heterotrophic eukaryotes.
• They obtain food from dead or decaying organic material. So, they are called saprophytes
• They have cell wall made of a tough complex sugar called chitin.
• For example:- Yeast and mushroom etc.

• Symbiotic relationship:- The permanent mutually dependent relationship between two organism is called symbiotic relationship. Ex:- Lichen, which is a symbiotic relationship between cyanobacteria and fungi.

Plantae:-

• These are multicellular eukaryotes with cell wall.
• These are autotrophs.
• They have chlorophyll for photosynthesis.

Animalia:-

• These are multicellular eukaryotes without cell wall.
• These are heterotrophs.

Plantae:-

Thallophyta:-

• They do not have well differentiated body design.
• The plants in this group are commonly called algae.
• These plants are predominantly aquatic.
• Ex:- Spirogyra, Ulothrix, Cladophora and Chara.

Bryophyta:-

• These are called the amphibians of the plant kingdom.
• The plant body is commonly differentiated to form stem and leaf like structure.
• They have no specialised tissue for conduction of water and other substances.
• Ex:- Moss (Funaria) and Marchantia etc.

Pteridophyta:-

• The plant body is differentiated into roots, stems and leaves.
• They have specialised tissue for the conduction of water and other substances.
• Ex:- Marsilea, ferns and horse-tails.

• Cryptogamae:-
  • They have naked embryos that are called spores.
  • They have hidden reproductive organs.
  • The thallophytes, the bryophytes and the pteridophytes fall in this group.
• Phanerogams:-
  • They have well-differentiated reproductive tissues.
  • They produce seeds.
  • Seeds consist of embryos along with stored food.
  • This group is further classified, based on whether the seeds are naked or enclosed in fruits, into two groups: gymnosperms and angiosperms.

Gymnosperms:-

• They have naked seeds.
• They are usually perennial ,evergreen and woody.
• Ex:-Pine, Deodar etc.

Angiosperms:-

• They are flowering plants.
• The seeds are enclosed in fruits.
• The angiosperms are divided into two groups on the basis of the number of cotyledons:
  • Monocotyledonous/Monocots:- Plants with seeds having a single cotyledon are called monocots. Ex:- Paphiopedilum.
  • Dicotyledonous/Dicots:- Plants with seeds having two cotyledons are called diocots. Ex:- Ipomoea.

Animalia:-

Porifera:-

• These are non motile animals.
• There are holes or ‘pores’, all over the body.
• These animals are covered with a hard outside layer or skeleton.
• They have very minimal differentiation.
• They are mainly found in marine habitats.
• They are commonly called sponges.
• Ex:- Sycon, Spongilla, Euplectelia, etc.

Coelenterata:-

• These animals live in water.
• They show more body design differentiation.
• They have cavity in the body.
• The body is made of two layers of cells.
• Some of these species live in colonies (corals), while others have a solitary like–span (Hydra).
• Ex:-Jellyfish, Hydra, Sea anemones etc.

Platyhelminthes:-

• The body is bilaterally symmetrical.
• The body is triploblastic.
• There is no true internal cavity or coelom.
• The body is flattened so they are called flatworms.
• They are either free living or parasitic.
• Ex:- Planareia, Liverfluke, Tape worm etc.

Nematoda:-

• The body is bilaterally symmetrical and triploblastic.
• The body is cylindrical.
• They have a sort of body cavity or pseudocoelom.
• These are parasitic worms causing diseases like filarial worms causing elephantiasis or the worms in the intestine (roundworms or pinworms)
  Ex:-Ascaris, Wuchereria.

Annelida:-

• These are bilaterally symmetrical and triploblastic.
• They have a true body cavity.
• They are founded in marine waters , fresh water as well as on land
  Ex:-Earthworm, Nereis, Leech.

Arthropoda:-

• It is the largest group of animals.
• These are bilaterally symmetrical and segmented .
• They have open circulatory system .
• The coelomic cavity filled blood .
• They have jointed legs .
• Ex:-Mosquito, Housefly, Butterfly, Spider.

Mollusca:-

• These animals are bilaterally symmetrical .
• The coelomic cavity is reduced.
• They have an open circulatory system.
• They have kidney-like organs for excretion.
• They have a foot for moving around.
• Ex:-Chiton , pila , octopus.

Echinodermata:-

• These are free living marine animals.
• These are spiny skinned organisms.
• They are triploblastic.
• They have a coelomic cavity.
• They have skeleton made of hard calcium carbonate.
• Ex:- Starfish, sea urchins.

Protochordata:-

• These are bilaterally symmetrical and triploblastic.
• They have a coelom.
• They have a notochord which is shown at least at some stages of their lives.
• These are marine animals.
• Ex:- Balanoglossus, Herdemania and Amphioxus.

Vertebrata:-

• They have a true vertebral column and internal skeleton.
• They are bilaterally symmetrical, triploblastic and segmented.
• They are coelomate.
• They show complete body differentiation.

Vertebrates are grouped into five classes:-

Pisces:-

• These are fish.
• They are aquatic animals.
• Their skin is covered with scales/plates.
• They have gills.
• They are cold blooded.
• They have two chambered heart.
• They lay eggs.
• The body is streamlined.
• Some of them have skeletons made entirely of cartilage, such as sharks, and some have a skeleton made of both bone and cartilage, such as tuna or rohu.

Amphibia:-

• They have lack of scales.
• They have three chambered heart.
• They have mucus glands in skin.
• They lay eggs.
• Respiration is through either gills or lungs.
• They are found both in land and in water.
• Ex:- Salamanders, Toads, Frogs etc.

Reptilia:-

• These animals are cold blooded.
• They have scales.
• They breathe through lungs.
• Most of them have a three chambered heart, but crocodiles have four chambered heart.
• They lay eggs on land.
• Ex:- Turtle, Chameleon, King Cobra, Flying lizard (Draco), House wall Lizard (Hemidactylus) etc.

Aves:-

• They are warm blooded animals.
• They have four chambered heart.
• They lay eggs.
• They have a outside covering of feathers.
• They breathe through lungs.
• The two forelimbs are modified for flight.
• All birds fall in this category.
• Ex:- Ostrich (Struthio camelus), Duck , Pigeon, Sparrow, Crow etc.

Mammalia:-

• They are warm blooded.
• They have four chambered heart.
• They have mammary glands for production of milk.
• There skin has hairs as well as sweat and oil glands.
• Most of them produce live young ones.
• Some of them like platypus and echidna lay eggs.
• Ex:- Cat, Human, Rat, Bat, etc,