mollusca - ANSWER (snails, clams, squids, octopuses) have a soft body that in
many species is protected by a hard shell
porifera - ANSWER sponges
Echinodermata - ANSWER radially symmetrical marine invertebrates including e.g.
starfish and sea urchins and sea cucumbers
chordata - ANSWER vertebrates animals; includes man
Platyhelminthes - ANSWER flatworms
cnideria - ANSWER Polyp and Medusa; radial symmetry; tentacles with stinging
cells; i.e. jellyfish, hydra, coral, sea anemones,
Annelida - ANSWER segmented worms
descriptive embryology - ANSWER study of the mechanisms of development
documenting the development of a blastomere
observational experiments
developmental mechanics - ANSWER what causes changes in development stages
tissue folding to form neural cord
experimental experiments
, acrosome - ANSWER tip of sperm with digestive enzyme which allows fusion and
penetration of the egg
How does the egg prevent polyspermy? - ANSWER the fertilization membrane will
lift off the eff to block any other sperm from entering
fast block - ANSWER occurs when the egg's plasma membrane depolarizes after
sperm binds to the egg. This depolarization creates an electrical barrier
slow block - ANSWER used by eggs from almost all sexually reproducing animals.
It occurs when the egg releases material into the extracellular space that hardens
the egg's fertilization membrane
What is cleavage? - ANSWER rapid cell division without growth forms blastomeres
blastomeres - ANSWER Smaller cells produced by cleavage during mitotic cell
division
animal pole vs vegetal pole - ANSWER Animal - very active cleavage, little yolk
Vegetal - very slow cleavage, lots of yolk
radial cleavage - ANSWER cleavage planes are either parallel or perpendicular to
the vertical axis of the embryo
deuterostomes
spiral cleavage - ANSWER planes of cell division are diagonal to the vertical axis of
the embryo
rotational cleavage - ANSWER In mammals, cleavage pattern in which second
cleavages are perpendicular, meridional in one blastomere and equatorial in the
other.
cleavage of deuterostomes - ANSWER radial and indeterminate
cleavage in protostomes - ANSWER spiral and determinate
isolecithal egg - ANSWER small egg, little yolk, evenly distributed, cleavage divides
completely
holoblastic cleavage most invertebrates and simple chordates
mesolecithal egg - ANSWER medium egg, moderate yolk with most at vegetal pole
meaning the cleavage occurs at the top
holoblastic cleavage Amphibians are a phylum that have mesolecithal cleavage
Holoblastic cleavage - ANSWER A type of cleavage in which there is complete
division of the egg, as in eggs having little yolk (sea urchin) or a moderate amount of
yolk (frog).
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