IMPORTANT TERMS:
· Aboral:Opposite side of the body to the mouth.
· Amnion:Third embryonic membrane around the embryo which provides aquatic environment for development on land.
· Amphiblastula:The free swimming larval stage of sponges.
· Autotomy:Power of losing body parts in self defence.
· Bipinnaria:The larval form of asteroid echinoderms.
· Blastocoel: The fluid filled cavity within the blastula, also known as segmentation cavity.
· Coelom:The fluid filled body cavity lined with mesoderm.
· Coelenteron:The sac-like central cavity of cnidarians, also known as gastro-vascular cavity.
· Crypsis:A type of colouration in which an animal helps to camofluage in its natural environment.
· Digenetic:A type of life cycle of some parasites that completes in two hosts.
· Germ layers: The layers of cells in gastrula from which various organs are formed.
· Glochidium:The larval form found in bivalve molluscs.
· Haemocoel: The blood filled body cavity found in molluscs and arthropods.
· Haemolymph:The whitish blood having no pigment found in arthropods.
· Mimicry:Refers to the resemblance of one organism to another or to any other natural object for the purpose of concealment, protection or some other advantage.
· Nacreous:An iridescent pearly inner surface of some bivalve shell.
· Nuptial Flight: A flight for copulation found in some insects.
· Neoteny:Refers to the development of gonads (testes/ovaries) and normal sexual reproduction by a larva. It occurs in axolotl (larva of tiger salamander).
· Pheromones:Secretions of glands, generally acting as sex attractant.
· Planula:The free swimming ciliated larva found in cnidarians.
· Parthenogenesis:Development of an egg (ovum) into a complete individual without fertilization by a sperm. Drones (males) of honey bees are formed by parthenogenesis.
· Paedogenesis: Refers to the development of gonads and/or production of young ones by immature larval or pre adult animal, eg., (i) Sporocyst (larva) and Redia (larva) of liver fluke produce radia and cercaria(larva) by parthenogenesis respectively (ii) Axolotl (larva) of salamander) develops gonad and starts producing young ones by sexual reproduction.
· Radula:The file-like transverse row of chitinous teeth found in the buccal cavity of most molluscs.
· Regeneration:Restoration of lost part (=epimorphosis) or reconstruction of whole body for a small part of the organisms body (=morphallaxis) is called regeneration.
· Schizocoel:Coelom formed by the division of mesoderm as in annelids.
· Sanguivorous:Organisms feeding upon blood of other animals such as Leeches.
· Thecodont:Teeth embedded in sockets of jaw bones.
· Trochophore:The ciliated larval form found in annelids and some molluscs.
· Ungulate:Hoofed animals.
· Veliger:A modified form of trochophore larva found in gastropods.
Worm Castings: Compacted pallets of faeces of eartworms laid as heaps.
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