Q’S AND A’S
animals - ANSWER-multicellular, heterotrophic eukaryotes with tissues developed
from embryonic layers
collagen - ANSWER-the most abundant structural protein that helds together the
animal cells
cleavage - ANSWER-The process of cytokinesis in animal cells, characterized by
pinching of the plasma membrane; specifically, the succession of rapid cell divisions
without growth during early embryonic development that converts the zygote into a
ball of cells.
blastula - ANSWER-The hollow ball of cells marking the end stage of cleavage
during early embryonic development
gastrulation - ANSWER-developmental process in which three distinct cell layers
form in an embryo: the endoderm, mesoderm, and ectoderm
gastrula - ANSWER-a stage of embryonic development characterized by the
differentiation of the cells into the ectoderm and endoderm germ layers and by the
formation of the archenteron
larva - ANSWER-A free-living, sexually immature form in some animal life cycles that
may differ from the adult in morphology, nutrition, and habitat.
metamorphosis - ANSWER-the marked and rapid transformation of a larva into a
juvenile, which resembles the adult but is not yet sexually mature.
Hox genes - ANSWER-Series of genes that controls the differentiation of cells and
tissues in an embryo
choanoflagellets - ANSWER-closest living relatives to the animalia
Ediacaran biota - ANSWER-An early group of soft-bodied, multicellular eukaryotes
known from fossils that range in age from 565 million to 550 million years old.
Cambrian explosion - ANSWER-A burst of evolutionary origins when most of the
major body plans of animals appeared in a relatively brief time in geologic history;
recorded in the fossil record about 535 to 525 million years ago.
radial symmetry - ANSWER-body plan in which body parts repeat around the center
of the body; characteristic of sea anemones and sea stars