Class 11, Kingdom Animalia - In-vertebrata | Non-chordates - English / Tamil - for Class 11 | NEET

 Invertebrata | Non-chordates

•      Phylum - Porifera (pore bearing) Eg. Sponges

•      Phylum - Cnidaria (Coelenterata) - Eg. Hydra

•      Phylum - Ctenophora (comb jellies)eg. pleurobrachia

•      Phylum - Platyhelminthes (flat worms )eg. Tape worm

•      Phylum - Aschelminthes (round worms )eg. Ascaris

•      Phylum - Annelida (annulus little ring )eg. Earth worm

•      Phylum - Arthropoda – (jointed legs) eg. cockroach

•      Phylum - Mollusca - (soft bodied and shelled) eg. Mussel

•      Phylum - Echinodermata - (spiny skinned) eg. Star fish

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      Phylum - Porifera - Ex. Sponges

•      (L. Poros – Pore, ferre – to bear)

•      Pore bearing animals – commonly called sponges.

•      Marine, few – freshwaters, either radially symmetrical or asymmetrical, multicellular level of organization.

•      Have water canal system or canal system

•      Minute pores - Ostia → Spongocoel → Osculum(out) – food gathering, circulation, respiration and removal of waste.

•      Choanocytes/ collar cells line in the spongocoel, canals.

•      Nutrition is holozoic, intracellular digestion

•      Skeleton made up of spicules/ sponging fibres.

•      Hermaphrodite – male and female organs present on the same organism.

•      Reproduce asexually by budding, gemmule formation or fragmentation.

•      sexually by formation of gametes.

•      Development is indirect – parenchymula, amphiblastula

•      Ex. Spongilla (fresh water spong), Euplectella (Venus flower basket), Euspongia (bath sponge).

Phylum - Cnidaria (Coelenterata) - Ex. Hydra

•      (G. knode – needle or sting cells)

•      Previously called Coelenterata.

•      Aquatic /marine

•      Sessile (fixed ) /free swimming

•      Radially symmetrical

•      Have cnidoblasts / cnidocytes with stinging cells or nematocyst on tentacles.

•      Used for defense, anchorage and to capture the prey.

•      Tissue level of organization diploblastic.

•      Central vascular cavity or coelenteron (serves both digestion, circulatory function).

•      Mouth or hypostome.

•      Digestion - extracellular and intracellular

•      Corals have skeleton made of calcium carbonate.

•      Exhibit two basic forms - polyp and medusa.

•      Polyp is sessile, cylindrical (e.g. Hydra)

•      Medusa is free living, umbrella shaped (jelly fish)

•      Alternation of generation (Metagenesis) - where polyp forms medusa asexually, medusa forms polyp sexually. (Ex. Obelia)

•      Development is indirect – ciliated planula larva.

•      Ex. - Hydra, Physalia (Portugese man of war), Adamsia (Sea anemone), Pennatula (Sea pen), Sea fan, Meandrina (Brain coral).

 Phylum - Ctenophora eg.  Pleurobrachia

•      (G. Ktenos-comb; phoros- bearing)

•      Marine , biradially symmetrical, diploblastic

•      Tissue level of organization

•      Body bears 8 rows ciliated comb plates (comb jellies or sea walnuts) - help in locomotion

•      Digestion by intra and extracellular

•      Bioluminescence – (the ability of a living organism to emit light) is well developed.

•      Special cells – lasso cells or colloblasts – help in food capture.

•      Sexes are not separate (monoecious)

•      Reproduce by sexual reproduction

•      Fertilization is external and indirect development (Cydippid larva) .

•      Ex. - Pleurobrachia and ctenoplana

Phylum – Platyhelminthes ( flat worms ) eg. Tape worm

•      (G. Platy – broad or flat; helmin – worm)

•      Dorso-ventrally flattened body – flat worms.

•      Endoparasites, bilaterally symmetrical

•      Organ level of organization,

•      Triploblastic - acoelomate

•      Hooks and suckers are present – serves as organs of attachment.

•      Liver fluke – an incomplete digestive system.

•      Polyembryony – in liver fluke.

•      Flame cells for osmoregulation and excretion.

•      Sexes are not separate (monoecious) – fertilization is internal and development is through many larval stages (cercaria, redia, miracidium, sporocyst).

•      High regeneration capacity in Planaria

•      Ex.- Taenia solium (Tape worm), Planaria, Fasciola hepatica (Liver fluke), Schistosoma (blood fluke).

Phylum - Aschelminthes (round worms ) eg. Ascaris

•      (G. Askes-cavity, helminths – worms)

•      Previously called as Nematoda.

•      Body is circular shape in cross section – hence they are called round worms.

•      Free living, aquatic, terrestrial parasitic

•      Organ system level of body organization

•      Bilaterally symmetrical and triploblastic

•      Pseudocoelomate, organ system level of organisation.

•      Covered by a transparent, tough protective collagenous layer – cuticle.

•      Digestive system is complete (mouth, muscular pharynx and anus)

•      Excretory system – renette glands.

•      Sexes are separate (dioecious), exhibit sexual dimorphism (females – longer than males).

•      Fertilization is internal and development is direct or indirect.

•      Majority oviparous (e.g. Ascaris), few are ovoviviparous (Wuchereria).

•      Ex. Ascaris lumbricoides (round worm), Wuchereria (filarial worm ), Ancylostoma (hookworm) and Enterobius vermicularis (pin worm).

 Phylum – Annelida (segmented worm ) eg. Earth worm

•      (L. annulus – a ring, and G. edios-form)

•      First segmented animals to evolve.

•      Aquatic/terrestrial

•      Free living/ parasites

•      Organ system level of body organization

•      Bilaterally symmetrical

•      Triploblastic

•      Metamerically segmented – coelomate

•      Metamerism: The elongated body is metamerically segmented, the body surface is divided into segment or metamers. Internally the segments are divided from one another by partitions – septa.

•      Marine Nereis possess parapodia (lateral appendages)- helps in swimming.

•      Chitinous setae – Earthworms, suckers-leech – help in locomotion.

•      Possess longitudinal, circular muscles - locomotion.

•      Haemoglobin and chlorocruorin (green) – respiratory pigment.

•      Closed circulatory system

•      Nephridia help in osmoregulation and excretion .

•      Dioecious(sexes are separate)

•      Earthworm – monoecious, Neries, leeches – dioecious.

•      Reproduction is sexual, development is direct or indirect – includes a trochophore larva.

•      Eg. Hirudinaria (leech ), Nereis (sand worm) and Pheretima ( earth worm ).

Phylum – Arthropoda – (jointed legs) eg. Cockroach

•      (G. arthros-jointed; podes – feet)

•      Largest phylum of the Kingdom Animalia, 2/3 are insects (2-10 million- species)

•      Organ system level of body organization

•      Bilaterally symmetrical

•      Segmented and coelomate

•      Chitinous exoskeleton- for protection, prevents water loss.

•      Moulting or ecdysis – shed off periodically.

•      Body has head, thorax and abdomen with a body cavity called haemocoel.

•      Have jointed appendages (organs for locomotion )

•      Gills / book gills / Book lungs / tracheal system - Respiratory organs.

•      Open circulatory system.

•      Sense organs are antennae, eye, statocysts (organs of balance / equilibrium)

•      Fertilization is internal.

•      Excretion by malpighian tubules.

•      Sexes are separate (Dioecious), Oviparous

•      Development may be direct/ indirect

•      Economic importance - Apis (Honey bee), Bombyx (Silkworm), Laccifer (Lac insects).

•      Vectors- Anopheles, Culex, Aedes (Mosquitoes), Housefly.

•      Aquatic –crab, prawn, lobster,limulus(living fossil).

•      Did you Know?

•      The same diameter of Spider silk is five times stronger than steel.

•      A Boeing 747 could be stopped in flight by a single pencil width strand of spider silk.

Phylum - Mollusca (soft bodied and shelled) eg. Mussel

•      (L. molluscs – soft bodied)

•      Second largest phylum

•      Terrestrial and aquatic

•      Organ system level of body organization

•      Bilaterally symmetrical

•      Triploblastic and Coelomate

•      Calcareous shell and unsegmented body with head, muscular foot and visceral hump or visceral mass.

•      Soft spongy layer of skin - over the visceral hump forms mantle.

•      Mantle cavity: The space - the visceral mass, mantle (pallium).

•      Gills for respiration.

•      Head has sensory tentacles

•      File like rasping organ found in the mouth for feeding – called radula. Radula- absent in bivalves.

•      Sense organs – tentacles, eyes and ospharidium (to test the purity of water).

•      Excretory organs – nephridia.

•      Open circulatory system – except cepahalopods.

•      Blood contains - Haemocyanin (blue) - copper (respiratory pigment).

•      Sexes are separate (Dioecious), Oviparous

•      Indirect development – veliger larva (a modified trochophore larva).

•      Ex. Pila (Apple snail), Lamellidens (Mussel), Pinctada (Pearl oyster), Sepia (Cuttle fish), Loligo (Squid), Octopus (Devil fish).

Phylum - Echinodermata: (spiny skinned) eg. Star fish

•      (G. Echinos – spiny; dermos – skin)

•      Spiny skin has exoskeleton which is calcareous ossicles – hence the name Echinodermata (spiny skin).

•      Marine, organ system level of body organization

•      Radially symmetrical, coelomate, Triploblastic

•      Mouth - ventral side and anus - dorsal side.

•     Distinct feature - Have water vascular system or ambulacral system with tube feet or podia - help in locomotion, to capture and transport of food and for respiration.

•      Complete digestive system – with mouth on ventral side, anus on dorsal side.

•      Excretory system is absent.

•      Circulatory system – open type without heart, blood vessels.

•      Dioecious and fertilization is external, development is indirect with free swimming larva – bilaterally symmetrical.

•      Some exhibit autotomy – remarkable powers of regeneration (eg. Star fish)

•       Ex. Asterias (Starfish), Echinus (Sea urchin), Antedon (Sea lily), Cucumaria (Sea cucumber), Ophiura (Brittle star).