Metazoa 1

heterotrophic

heterotrophic

require a source of food, ingesting other living or dead organisms

body plan

the morphology of an animal, determined by developmental cues

germ layers

ectoderm, endoderm, and mesoderm

cleavage

a series of mitotic cell divisions subdividing a fertilized eff (zygote) to form a multicellular embryo

blastomeres

the cells resulting from subdivision of the material of the egg where cells are not growing, only dividing

blastula

a hollow structure that forms after a solid morula, 16-32 cell stage of development of an animal

gastrulation

results in the formation of the primitive gut (archenteron) or digestive cavity, and the formation of the embryonic germ layers

radial symmetry

the arrangement of body parts around a central axis

bilateral symmetry

the division of the animal through a midsagittal plane, resulting in two superficially mirror images, right and left halves, such as those of a butterfly

diploblasts

animals that have a nonliving middle layer between the endoderm and ectoderm

triploblasts

animals with three tissue layers (endoderm, ectoderm, and mesoderm)

protostomes

“mouth first”, the mouth develops at the blastopore

Deuterostomes

“mouth second”, the mouth develops at the other end of the gut and the anus develops at the site of the blastopore

combs

groups of cilia Ctenophore use for swimming

colloblasts

Ctenophore cells that are sticky and adhere to prey

mesoglea

a middle layer of jelly-like material in ctenophora and cnidaria

nerve net

diffuse set of neurons present in the inner layer of the epidermis

pinacocytes

epithelial-like cells that form the outermost layer and encloses a jelly-like substance called mesohyl

mesohyl

a jelly-like substance found between the outer layer and the feeding chambers of a sponge that contains collagenous fibers

choanocytes

generates a directed water current through the sponge and traps and ingest microscopic food particles by phagocytosis

spicules

small bone-like structures that support sponges, made of silica or calcium carbonate

spongin

a modified type of collagen protein that forms the fibrous substance, also supports sponges

cnidocyte

stinging cell found in Cnidaria that contains nematocysts

nematocysts

large stinging organelles that usually contain barbs at the base of a long coiled thread

polyp

one of the body plans found in Cnidarians, a tulip-like "stalk" form (sessile as adults)

medusa

one of the body plans found in Cnidarians, a "bell" form (motile as adults)

sessile

live permanently attached to substrate

incomplete metamorphosis

larval forms are smaller, wingless versions of adult

complete metamorphosis

larval stage differs greatly in body plan compared to adults

Hox genes

master control gene that can turn on or off large numbers of other genes during embryogenesis, responsible for general body plan of an organism

rotational symmetry

division in any direction along oral/oboral axis results in two identical halves, with one copy rotated 180 degrees

(sponge) exoskeleton

one form of support for Porifera, made of calcium carbonate

amoeboid motion

sliding movement initiated my extension of pseudopodia with the rest of the cell following

closest extant relatives of animals

choanoflagellates

fertilization

Process in sexual reproduction in which male and female haploid gametes cells combine to form a new cell

coelom

fluid-filled internal cavity derived from mesoderm

blastopore

the opening of the central cavity of an embryo in the early stage of development.