Ch 51

Question 1

preformation vs epigenesis

Answer 1

preformation is the idea that the sperm or egg contains a tiny adult that just grows once implanted in the uterus, epigenesist is the idea that the form of an animal emerges from a relatively formless egg; preformation obviously isn’t what occurs, epigenesis is

Question 2

stages of development

Answer 2

fertilization, cleavage, gastrulation, neurulation, organogenesis, and growth

Question 3

morphogenesis

Answer 3

the development of form, occurs through pattern formation

Question 4

pattern formation

Answer 4

a series of events in which cells may communicate by signaling, migrate, undergo changes in shape, and even undergo apoptosis (programmed cell death)

Question 5

apoptosis

Answer 5

programmed cell death

Question 6

describe the four processes involved in fertilization

Answer 6

1:contact and recognition occur between noncellular egg coverings and sperm, 2:sperm entry is regulated to prevent interspecific fertilization and polyspermy, which is fertilization of the egg by more than one sperm, 3:fertilization activates the egg, triggering the events of early development, 4:sperm and egg pronuclei fuse and initiate DNA synthesis

Question 7

coverings of echinoderm eggs vs. coverings of mammalian eggs

Answer 7

echinoderm eggs are covered by the vitelline envelope and the jelly coat, mammalian eggs are covered by a zona pellucida

Question 8

What are the 4 extraembryonic membranes?

Answer 8

chorion: used for gas exchange and combines with the endometrium to form the placenta (connection to mom), amnion: bathes and protects the fetus (filled with amniotic fluid), allantois and yolk sac: just know that humans have them