ATHENA GLOBAL SCHOOL GRADE: IX

Transcription

1 ATHENA GLOBAL SCHOOL GRADE: IX SUB: SCIENCE CHAPTER-7-DIVERSITY IN LIVING ORGANISMS The Hierarchy of classification: Five kingdom of classification: (i) Monera (ii)protista (iii)fungi (iv)plantae (v)animalia Woese classified Monera kingdom into (1)Archae bacteria (2)Eubacteria Subgroups: Kingdom(i)Phyllum(animal) (ii)division(plants) Species: The organisms in a species can interbreed with each other. (i)monera: * No defined nucleus. * Some have cell wall but some don t * No cell organelles * Mode of nutrition autotrophic or heterotropic *example-bacteria, blue green algae and cyanobacteria. (ii) PROTISTA: *Unicellular eukaryotes

2 * Have appendages cilia, flagella * Nutrition-autotrophic or heterotrophic * example: unicellular algae, diatoms, protozoans (iii) FUNGI: *Heterotrophic,eukaryotic organisms * They feed on dead and decaying matter. So they are called saprophytes * cell wall present and made up of tough complex sugar-chitin Examples: yeast and mushroom Symbiotic relationship: *In this type of relationship two organisms will mutually help each other * Example: Zichens it is a combination of fungi and blue green algae (iv) PLANTAE: *Multicellular eukaryotes * They have cell wall * Autotropes Kingdom plantae: Thallophyta Bryophyta Pteridophyta Gymnosperm Angiosperm (a)thallophyta: * No well differentiated body design * Aquatic * Example: Algae, spirogyra, ulothrix (b) Bryophyta : * Amphibians of plant kingdom * Body differentiated to form stem and leaf like structure * No specialized tissue for conduction

3 * Example: Moss, marchantia Pteridophyta: *Body differentiated into root, stem, leaves * specialized tissues for conduction of water * examples: ferns, marsilia, horsetails * Thallophyta,bryophyte,pteridophyta have naked embryos * Reproductive organs are hidden * So called cryptogams * Phanerogams have well differentiated reproductive tissues * Seeds present as embryo has stored food (d)gymnosperms: * Naked seeds * Gymnosperms-gymno means naked and sperma means seed * perennial * Woody * Examples: pines,deodar (e) Angiosperms: *Angio means covered,sperms means seed * Seed inside fruit * Flowering plants * Embryos in seeds have cotyledons (v) ANIMALIA: Phylums under the kingdom animalia: (a) Porifera (b) Coelentrata Platyhelminthes

4 (d) Nematoda (e) Annelida (f) Arthropoda (g) Mollusca (h) Echinodermata (i) Proto chordate (j) Vertebrata (a) PORIFERA: *Organisms have holes * Non motile attached to solid support * Canal system helps in circulating water * Hard outer layer *Minimal differentiation and divided into tissues * They have marine habitats *example:spongilla,sycorn (b)colenterata(cnidaria) * Animals in water * Body is differentiated * Body cavity is present * Two layers of cell are present- inside the body and outside the body * colonies- corals, solitary hydra *example: Jelly fish, sea anemone PLATYHELMINTHES: *Complex * Bilaterally symmetrical * Triploblastic-3 layers of cell

5 * Outside and inside body linings and some organs developed * Tissue formation * No internal cavity or coelem * Flat body dorsoventrally (top to bottom) * Free living planaria * Parasitic liver flukes (d) NEMATODA: * Bilaterally symmetrical * Triploblastic * Cylindrical body * Tissues but no real organs * Pseudocoelem * Parasitic worms-filarial worms causes elephantiasis * Worms in intestine round worms,pinworms * Example: ascaris,uruncheria (e) ANNELIDA: * Bilaterally symmetrical * Triploblastic * True body cavity * True organs packaged in human structure * Organ differentiation * Segments lined one after another from head to tail * Found in fresh water,marine also in land * example: earthworm, zilch (f) ARTHROPODA: * Bilaterally symmetrical

6 * Largest group * Segmented * Open circulatory system * Coelomic cavity * Jointed legs * Prawns, butterfly, housefly, spider, scorpion, crabs (g) MOLLUSCA: * Bilaterally symmetrical * Coelomic cavity reduced * Little segmentation * Open circulatory system * Kidney like organ for excretion * Foot for moving * Snails,mussles (h) ECHINODERMATA: * Echinos means hedgehog,derma-skin * Spiny skinned organism * Free living * Marine * Triploblastic * Coelomic cavity * Water driven tube system * Hard calcium carbonate structure as skeleton * Star fish,sea urchin (i) PROTOCHORDATA: * Bilaterally symmetry

7 * Triploblastic * Coelomic cavity * Notochord present at some stages in lives * Muscles attached for movement * Marine * Balanaglossus, herdmania, amphioxus (j) VERTEBRATA: * True vertebral column * Internal skeleton * Bilaterally symmetry * Triploblastic * Coelomic cavity * Segmented * Complex * Differentiation of body tissues and organisms CHORDATES have- *Notochords *Dorsal nerve chord *Triploblastic * Paired gill pouches * Coelomate PHYLUM VERTEBRATES have the following classess: (i) PISCES: Pisces Amphibians Reptilia Aves Mammalia

8 *Fish * Aquatic * Skin covered with scales or plates * Oxygen dissolved in water,breathe by gills * Steamlined body * Muscular tail used for changing direction * Cold blooded *2 chambered heart * They lay eggs * Skeleton made up of cartilage. example-shark * Skeleton made up of bone and cartilage, example: Tuna and Rohu (ii)amphibians: *No scales * Mucus gland in skin *3 chambered heart * Respiration by gills or lungs * They lay eggs * Found in water and land * Frog, toad, salamander (iii) REPTILES: * Cold blooded * Have scales * Breath through lungs *3 chambered heart * Lays eggs on land with tough coverings * Snakes,turtles, lizard

9 (iv) AVES: *Birds *Warm blooded *4 chambered heart * Lays eggs * Feathers *2 forelimbs modified to wings * Lungs to breathe (v) MAMMALIA: * Warm blooded *4 chambered heart * Mammary gland which produces milk * Hair on skin * sweat and oil glands * produce young ones * Platypus and echidna lays eggs * Kangaroos have poorly developed young ones BINOMIAL NOMENCLATURE: It was introduced by Carolus Linnaeus The process of giving the scientific name to the organisms (plants,animals, and microbes) is called binomial nomenclature. The scientific name has two parts: (a) generic name-genus name (b) Specific name-species name *The conventions followed while writing the scientific names are: (i) The name of the genus begins with the capital letter (ii)the name of the species begins with the small letter (iii)when printed the scientific name is given in Italics

10 (iv)when written by hand the genus name and the species name have to be underlined separately (v)examples: Humans Tigers Mango Hibiscus -Homo sapiens -Panthera tigris - Magnifera indica - Hibiscus rosasinensis