BI338 Invertebrate Zoology, Fall 2011 Brian K. Penney, Ph.D. Goulet 2320, Ph 641-7149, email: bpenney (at) anselm.edu

Main Page Definitions Phyla Other Links Review Section Projects

Definitions

ambulacra

body organizational unit of an echinoderm, comprised of rows of podia around a central groove, radial canals and nerves, etc.

ascon

sponge body form with a single flagellated pumping cavity

atrium

central chamber in a sponge, where water comes in from the choanocyte chambers and exits through the osculum

autonomous

cells that are capable of living and acting on their own

Bioerosion

destruction of solid material by burrowing of living animals (sponges, calms, etc.)

blastula

a stage of development where the embryo consists of a hollow ball of cells

book lungs

invaginations of exoskeleton with thin, highly folded structures called lamellae; for gas exchange in arachnids

calyx

Body form in entoprocts where body is like bud of flower sitting upside down (need to revise this)

choanocytes

cells possessing a collar of microvilli around a central flagellum, that are used to capture food in sponges and are a unique character of that phylum

cnidocytes

specialized sensory/effector cells of Cnidaria, used for stinging, attachment, or other uses. Unique to the phylum

colloblasts

exocytotic adhesive cell type unique to ctenophores

corona

specialized, ciliated feeding and locomotory organ found on anterior end of rotifers

dermal gills

special outpocketings of perivisceral coelomic lining through body wall; used for gas exchange in some echinoderms

dimorphic

undergoing two different adult morphologies

diploblastic

animal with body walls of only two cell layers, sometimes with non-cellular mesoglea between layers

ecdysis

molting in panarthropod phyla, regulated by the hormone ecdysone

facultative anaerobiosis

the ability to switch to functional anaerobic metabolism under anoxic conditions, and back again

Gas exchange
• aquatic have branched or folded gills; small crustaceans exchange over body surface
• arachnids have book lungs
• other terrestrial forms (insects, myriapods) with tracheae
gastrovascular cavity

a gut form where there is only one opening to the digestive tract, that serves as both mouth and anus. The gut typically also branches throughout the body to help distribute nutrients

gastrula

stage of development where the embryo consists of a hollow ball of cells where one point has begun to invaginate, starting a hollow tube that will become the digestive tract (endoderm)

hydrostatic skeleton

skeletal type where support and muscle antagonism are based on the incompressibility of fluids, whether in a large, fluid-filled space, or in the internal volume of muscular cells

introvert

type of pharynx seen in many blastocoelomates, where the structure everts via hydrostatic pressure and can be pulled inside the body with retractor muscles

leucon

sponge body form with many flagellated chambers connect via passive canals

lophophore

a ciliated, tentacular outgrowth arising from the mesosome and containing extensions of the mesocoel that surrounds the mouth but not the anus

mastax

unique modified pharynx found in rotifers

medusa

body form of cnidarians in which the oral axis faces towards the substrate, typically in pelagic forms; slightly flattened in comparison to polyps

mesenchyme

typical middle layer of sponges (mesohyl) and Cnidaria and Ctenophora that is mostly acellular and not a distinct tissue layer

mesoglea

non cellular (non-living), jelly like matrix between ectoderm and endoderm in Cnidaria

metamorphosis

major change in body form between larval and adult animals

osculum

larger excurrent pores in sponges

ossicles

porous skeletal elements of echinoderms formed from a single crystal of Calcium or magnesium carbonate

ostia

incurrent pores in sponges

parthogenesis

asesxual reproduction strategy wherein unfertilized eggs develop into mature organisms

pedicellariae

pincer-like formations of ossicles on the surface of some asteroids and echinoids; used for defense and cleaning body surface, rarely prey capture

polyp

Cnidarian body form in which the mouth faces upwards, away from the substrate. Typically in benthic forms.

radula

unique to Molluscs, feeding organ shaped like a spiked tongue

Renette cells

unique excretory structures found in some nematodes

rhyncocoel

mesodermally-derived compartment for housing the proboscis in nemertea

simultaneous hermaphrodites

animals that have functional versions of male and female reproductive systems at the same time

spicules

small skeletal elements made of hard material (Calcium carbonate, silica, etc.) seen in various invertebrates

spongin

a collagen-based material made into fibers, part of the supportive network of sponges

stereom

lattice-like channels through echinoderm ossicles

stroma

the living tissue filling the stereom of echinoderm ossicles

sycon

sponge body form with many flagellated pumping canals radiate from spongocoel

syncitial

made of cells with separate nuclei but not separated by plasma membranes

totipotent

cell type that can change into any cell type and is able to change back and forth among types; may spend different parts of life as different cell types

tracheae

branching tubules forming direct conduit from outside to bring air into blood and internal organs, allowing direct gas exchange

trophi

hard, jaw-like elements within the mastax of rotifers

zooxanthellae

symbiotic dinoflagellates that live within the tissues of cnidarians