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Class 9 Science

Diversity in Living Organism:Animalia Class 9th Science Notes

ANIMALIA

Porifera

  • These are non-motile organisms with pores all over their body leading to canal system that helps in circulating water throughout the body to bring in food and oxygen.
  • These animals are covered with a hard outside layer or skeleton
  • They are commonly called sponges example- sycon, spongilla and euplectelia.

Coelenterata

  • The body of these animals have a cavity, and is made up of two layers of cells.
  • Some of these species live in colonies(corals) while others have solitary like span(hydra).

Platyhelminthes

  • The body of these animals are bilaterally symmetrical, and have three layers of cells and are thus called triploblastic.
  • The three layers of cells allow outside and inside body linings as well as some organs to be made.
  • There is no true coelom, in which well developed organs can be accommodated.
  • The body is flattened from top to bottom i.e dorsoventrally.
  • Examples are parasites like liver flukes or free-living animals like planarians.

Nematoda

  • The nematoda body is bilaterally symmetrical, triploblastic and cylindrical.
  • There are tissues but no organs and have a psuedo cavity
  • Examples of nematoda are worms causing elephantiasis i.e filarial worms and pinworms found in intestines.

Annelida

  • Annelida are bilaterally symmetrical, triploblastic and have a true body cavity, allowing organs to be packed in body structure.
  • Differentiation occurs in a segmental fashion with segments lined up one after the other from head to tail.
  • Earthworms and leeches are examples of annelida.

Arthropoda

  • This is the largest group of animals
  • They are bilaterally symmetrical, segmented, and have an open circulatory system and jointed legs.
  • The coelomic cavity is blood filled in arthropoda.
  • Examples of arthropoda are prawns, butterflies, scorpions and crabs.

Mollusca

  • They are bilaterally symmetrical, have reduced coelomic cavity and little segmentation
  • They have open circulatory system, kidney like organs for excretion and use foot for moving around
  • Example are snails and mussels.

Echinodermata

  • These are spiny skinned, free-living marine animals.
  • They are triploblastic, have a coelomic cavity and have peculiar water driven tube system that they use for moving around
  • They have hard calcium carbonate structures as skeleton.
  • Examples of echinodermata are starfish and sea urchins.

Protochordata

  • They are bilaterally symmetrical, triploblastic and have notochord.
  • Notochord is a long rod-like support structure that runs along the back of the animal separating the nervous tissue from the gut.
  • Protochords may not have a proper notochord present at all stages in their lives
  • Examples of protochords are balanoglossus, herdermania and amphioxus.
Balanoglossus
Balanoglossus

Vertebrata

  • These animals have a true vertebral column and internal skeleton, allowing a completely different distribution of muscle attachment points to be used for movement.
  • They are bilaterally symmetrical, triploblastic, coelomic, segmented, dorsal nerve chord, paired gill pouches.

(i) Pisces

  • These are fish.
  • Their skin is covered with scales, they obtain oxygen dissolved in water using gills, have a streamlined body and a muscular tail.
  • They are cold-blooded, have two chambered heart and lay eggs
  • Examples are tuna, rohu and angler fish.

(ii)Amphibia

  • They lack scales, have three-chambered heart and mucus glands in their skin .
  • They respire through gills or lungs and lay eggs.
  • Examples of amphibia are salamanders and hyla.

(iii)Reptilia

  • These animals are cold-blooded, have scales, lay eggs, have three chambered heart and respire through lungs
  • Crocodiles have four-chambered heart.
  • Turtles, lizard and chameleon are examples of reptiles.
Nile crocodile

(iv)Aves

  • They are warm-blooded, have four chambered heart, lay eggs and have an outside covering of feathers.
  • They have two forelimbs modified for flight and breathe through lungs
  • Examples are ostrich, crow, sparrow etc.

(v)Mammalia

  • Mammals are warm-blooded, have mammary glands for production of milk to nourish young ones.
  • Their skin have hair as well as sweat and oil glands
  • Platypus and echidna lay eggs.
  • Examples of mammals are human, whale, bat etc.

Diversity in Living Organisms NCERT Solutions

Diversity in Living Organisms:NCERT Notes Class 9th

Categories
Class 9 Science

Diversity in Living Organisms:NCERT Notes Class 9th

  • Classification is the Science of arranging organisms in series of groups and subgroups on the basis of their similarities and dissimilarities.
  • Aristotle classified organisms on the basis of their habitat means the place where they live, in water, in air and on land
  • We look for similarities among the organism which allows us to put them into different classes and then study them as a whole.
  • Characteristics are details of appearance or behaviour.
  • The characteristics that decide the broadest divisions among living organisms are independent of any other characteristic in their effects on the form and function of the organism
  • The characteristic in the next level would be independent on the previous one and would decide the variety in the next level.
  • Once a body design comes into existence, it will shape the effects of all subsequent design changes.
  • Characteristics that come into existence are likely to be more basic than characteristics that have come into existence later.
  • Some group of organisms have ancient body designs that have not changed very much and are referred to as primitive or lower organisms.
  • Some group of organisms have acquired their particular body design relatively recently and are referred to as advanced or lower organism.

HIERARCHY OF CLASSIFICATION

  • The kingdoms proposed by whittaker proposed has five kingdoms: Monera, protista, fungi, plantae and animalia.
  • Woese introduced modification by dividing monera into archaebacteria and eubacteria.
  • Classification is done by naming the sub-groups at various levels in the following scheme: kingdom, phylum, class, order, family, genus, species.
  • A species include all organisms that are similar enough to breed and perpetuate.

Further classification is done by naming the subgroups at Various levels as given:
Kingdom→Phyllum\Divison→Class→Order →Family→Genus→Species
•Kingdom Monera
•Kingdom Protista
•Kingdom Fungi
•Kingdom Plantae
•Kingdom Animalia

Monera

  • Organisms in monera kingdom do not have a defined nucleus, organelles or multicellular body design.
  • They may or may not have cell walls
  • The mode of nutrition in organisms of monera kingdom can be autotrophic as well as heterophic.
  • This group includes bacteria, blue-green algae or cyanobacteria, mycoplasma and anabaena.

 

 

Protista

  • Organisms of this group are unicellular, eukaryotic and some of them organisms use appendages, such as hair-like cilia or whip-like flagella for moving around.
  • Examples are unicellular algae, diatoms and protozoans

Fungi

  • Organisms in this group are heterotrophic, eukaryotic and use decaying organic material as food and are therefore called saprophytes.
  • Many of these organisms have the capacity to become multicellular organisms at a certain stages in their lives.
  • They have cell walls made of tough complex sugar called chitin.
  • Yeast, mushrooms, aspergillus, penicillium and agaricus.

  • Some fungal species live in symbiotic relationships, and these life-forms are called lichens.

Plantae

  • The organisms in this group are are multicellular, eukaryotes, autotrophs and use chlorophyll for photosynthesis
  • All plants are included in this group.

Animalia

  • These include all organisms which are multicellular eukaryotes, without cell walls, and are heterotrophs.

PLANTAE

Thallophyta

  • Plants in this group are predominantly aquatic and do not have well-differentiated body design fall in this group.
  • Plants in this are commonly are called algae.
  • Examples of thallophyta are spirogyra, ulothrix, cladophora and chara.

Bryophyta

  • Bryophytes are called the amphibians of the plants.
  • The plants in this group do not have special tissues for conduction of water and other substances from one part of the plant body to another.
  • Examples of bryophyta are moss and marchantia.
  • The plant body is commonly differentiated to form stem and leaf-like structures.

Moss Biodevirsity

Pteridophyta

  • The plant body is differentiated into roots, stem and leaves and has specialised tissue for the conduction of water and other substances from one part of the plant body to another.
  • Plants of pteridophyta are cryptogamae.
  • Cryptogamae are plants with hidden reproductive organs.
  • Phanerogams are plants with well differentiated reproductive tissues that ultimately make seeds.

Gymnosperms

  • The plants of this group bear naked seeds and are usually perennial, evergreen and woody
  • Pines such as deodar are example of gymnosperms

Deodar
Deodar

Angiosperms

  • The seeds of these plants develop inside an organ.
  • These are also called flowering plants.
  • Plant embryos in seeds have cotyledons i.e seed leaves.
  • Monocots are plants with seeds having one cotyledon.
  • Plants with seeds having two cotyledons are called dicots.

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Read the second part of this lesson on Animal Kingdom notes for Class 9th science here