Lab 1 - Animal Development

Question 1

creates new cells through mitosis

Answer 1

cell division

Question 2

causes groups of cells to organize and move, to create an animal’s body shape

Answer 2

cell migration

Question 3

causes cells to develop different morphological features for specialization toward specific tasks

Answer 3

cell differentiation

Question 4

have very little yolk evenly distributed throughout the egg; undergoes holoblastic cleavage

Answer 4

Isolethical Eggs

Question 5

the cleavage furrow extends completely through the egg and completely separates daughter cells

Answer 5

holoblastic cleavage

Question 6

have a moderate amount of yolk concentrated at one end of the egg, referred to as the vegetal hemisphere, or pole; undergoes holoblastic cleavage but not as symmetrically

Answer 6

mesolecithal eggs

Question 7

have a large amount of yolk, which occupies most of the cell volume, the embryo is confined to a small disc at the opposite pole of the cell, the animal pole; undergoes meroblastic cleavage

Answer 7

Telolecithal eggs

Question 8

Because of the large, heavily concentrated yolk, cleavage is only partial, stopping at the border between the embryo and the yolk, and daughter cells remain connected to each other

Answer 8

meroblastic cleavage

Question 9

have a large amount of yolk, but the embryo forms a thin layer around the outside of the large, central yolk mass

Answer 9

Centrolecithal eggs

Question 10

when cleavage planes occur perpendicular or parallel to each other

Answer 10

radial cleavage

Question 11

When cleavage planes occur at oblique angles

Answer 11

spiral cleavage

Question 12

When cleavage planes are restricted to a dome of cytoplasm at one end of the yolk-laden cell

Answer 12

discoidal cleavage

Question 13

the embryo is represented by a solid mass of tiny cells (blastomeres) that continue to divide at a furious pace

Answer 13

morula stage

Question 14

solid mass of tiny cells

Answer 14

blastomeres

Question 15

characterized by a migration of cells toward the periphery of the embryonic sphere, creating a hollow cavity deep within the spheroid of cells

Answer 15

blastula stage

Question 16

The hollow, fluid-filled cavity within the blastula

Answer 16

blastocoel

Question 17

Several hours after the formation of the blastula, a small depression begins to appear at one end of the embryo, and cells begin to organize, move, and start to create the geometry of the animal’s body, more and more cells stream inward, deepening the invagination

Answer 17

early gastrula stage

Question 18

The opening to the outside of the embryo, marking the site of the inward migration of cells

Answer 18

blastopore

Question 19

The hollow tube that is created by the arrangement of invaginated cells

Answer 19

gastrocoel/archenteron

Question 20

By now, the individual cells are so small as to be indistinguishable from each other under normal magnification, At most, they appear as a flecking on the surface of the embryo, The archenteron has folded inward to the point of nearly connecting with the opposite end of the gastrula, and the shape of the gastrula has become markedly elongated, cell differentiation begins, and the primary tissue layers of the embryo start to form

Answer 20

late gastrula stage

Question 21

morphogenesis and organogenesis have begun by this stage

Answer 21

bipinnaria larva

Question 22

the development of the body shape

Answer 22

morphogenesis

Question 23

organogenesis

Answer 23

the differentiation of organ tissues

Question 24

one pole of the egg, appears lighter in coloration

Answer 24

vegetal pore

Question 25

one pole of the egg, darker pole, represents the portion of the egg where the embryo will develop

Answer 25

animal pole