Lab 2 - Fertilization and Early Development of Echinoderms

Question 1

surrounds unfertilized egg

Answer 1

vitelline membrane

Question 2

membrane that arise immediately after penetration of sperm cell and prevents further attemps of fertilization

Answer 2

fertilization membrane

Question 3

space between the membrane and the yolk

Answer 3

peri-vitelline area

Question 4

complete cleavage

Answer 4

holoblastic cleavage

Question 5

first and second cleavages

Answer 5

meridional and perpendicular to each other

Question 6

where does the third cleavage occur

Answer 6

equitorial plane, perpendicular to the first two cleavages

Question 7

where 4 micromeres are located

Answer 7

vegetal pole

Question 8

where 8 mesomeres are located

Answer 8

animal pole

Question 9

where 4 macromeres are located

Answer 9

in between

Question 10

where the pluricellular stage finishes

Answer 10

morula

Question 11

central cavity that is formed after morula

Answer 11

blastocoel

Question 12

what happens during blastula stage

Answer 12

1. ferilization membrane degraded
2. epithelium of cells of vegetal pole thickens and forms vegetal plate

Question 13

blastomeres at vegetal half migrate inward

Answer 13

invagination

Question 14

individual cells at the base of growing archenteron migrate to the inside

Answer 14

ingression of primary mesenchym cells

Question 15

final gastrula gives rise to what

Answer 15

pluteus larval stage