Introduction to Developmental Biology

Question 1

What is epigenesis?

Answer 1

Epigenesis is the idea that the embryo builds itself one step at a time, which is contrasted to preformation

Question 2

Contrast epigenesis with preformation

Answer 2

Preformation is the idea that a miniature human is contained within the sperm or the egg. Epigenesis is the idea that the embryo builds itself one step at at time.

Question 3

What are the two “big ideas” of embryology?

Answer 3

Differentiation and Morphogenesis

Question 4

What is differentiation?

Answer 4

Differentiation is the idea that different parts of the body are conferred from different parts of the embryo an at different times

Question 5

What is morphogenesis?

Answer 5

The dynamic movement of tissues and cells. Also, the study of the mechanisms by which shapes of the embryo arises.

Question 6

What are the two types of specification?

Answer 6

Autonomous and conditional

Question 7

What is autonomous specification? + example?

Answer 7

cell fate is determined at a very early age.

Mollusks

Question 8

What is conditional specification? + example?

Answer 8

cell fate is determined late. Divisions are variable. For example, 1/4 of the sea urchin larva can grow a full sea urchin.