ANIMAL DIVERSITY – I (NON-CHORDATES)

Axopodium: Fine, needle-like pseudopodium that has a central bundle of microtubules.
Axoneme: Microtubules and other proteins that compose the inner core of flagella and
cilia.
Basal body: An organelle equivalent to a centriole at the base of flagellum and cilia.
Binary fission: Asexual division that produces two similar individuals.
Body ciliature: Cilia distributed over the general body surface of ciliates.
Calcareous: Composed of calcium carbonate.
Centriole: Microscopic cylindrical structure, composed of microtubules, which is
situated at each pole of the mitotic spindle and is distributed during mitosis. There it
may function as a basal body and give rise to a flagellum or cilium.
Centrosome: Structure from which bundles of microtubules radiate outwards.
Cilium: Characteristic of many protozoan and metazoan cells, a motile outgrowth of
the cell surface that is typically short and its effective stroke is stiff and oar-like.
Conjugant: One of a pair of fused ciliates in the process of exchanging genetic
material.
Contractile vacuole: Large spherical vesicle responsible for osmoregulation in
protozoans and some sponge cells.
Cytostome: Cell mouth
Cyst: A parasite surrounded by a resistant wall or membrane (the wall or membrane
constitutes the cyst)
Disease: A specific morbid process that has a characteristic set of symptoms, and that
may affect either the entire body or any part of the body.
Ectoparasite: A parasite that lives on the outside of its host.
Encystment: Forming resistant cysts in response to unfavorable conditions such as lack
of food or desiccation.
Endoparasite: A parasite that lives within its host.
Endoral membrane: Ciliate undulating membrane that runs transversely along the right
wall and marks the junction of the vestibule and buccal cavity.
Exconjugant: Ciliates that have separated after sexual reproduction.
Filopodium: Pseudopodium that is slender, clear and sometimes branched.
Filter feeding: A type of suspension feeding in which particles (plankton and detritus)
are removed from a water current by a filter.
Flagellum: A characteristic of many protozoan and metazoan cells; it is typically long
and its motion is a complex whip-like undulation.