Exam 2

Question 1

Induction

Answer 1

A group of cells producing a signal to change the behavior of an adjacent set of cells.

Question 2

Differentiation

Answer 2

The process where a cell changes from one cell type to another.

Question 3

Pattern formation

Answer 3

The developmental process by which cells acquire different identities, depending on their relative spatial positions within the embryo.

Question 4

Morphogenesis

Answer 4

Process where cells move around and organize themselves into structures, organs and systems of the adult organism.

Question 5

Determination

Answer 5

The process by which portions of the genome are selected for expression in different embryonic cells.

Question 6

Gastrulation

Answer 6

Phase early in the embryonic development of most animals, during which the single-layered blastula is reorganized into a trilaminar (“three-layered”) structure known as the gastrula.

Question 7

Bicoid gene in Drossophilia

Answer 7

Provides essential information about the anterior-posterior axis.

Question 8

Archenteron

Answer 8

The cavity inside, which develops into the alimentary canal or digestive system.

Question 9

Acrosomal reaction

Answer 9

Sperm fusing with egg.

Question 10

Cortical reaction

Answer 10

The release of cortical granules from the egg which prevents polyspermy, the fusion of multiple sperm with one egg. The cortical reaction functions directly in the
formation of a fertilization envelope.

Question 11

Organogenesis

Answer 11

The primary germ layers differentiate into tissues and

organs.

Question 12

Blastocoel

Answer 12

Fluid-filled cavity, forms early.

Question 13

Blastomere

Answer 13

Type of cell produced by cleavage (cell division) of the zygote after fertilization.

Question 14

Meristems

Answer 14

Major function is to produce more cells.

Question 15

Vegative reproduction

Answer 15

Produces clones of the parent plant.

Question 16

Vestigial traits

Answer 16

Non-adaptive traits.

Question 17

Stabilizing selection

Answer 17

Results in a decrease of a population’s genetic variance when natural selection favors an average phenotype and selects against extreme variations.

Question 18

Directional selection

Answer 18

A population’s genetic variance shifts toward a new phenotype when exposed to environmental changes.

Question 19

Diversifying or disruptive selection

Answer 19

increases genetic variance when natural selection selects for two or more extreme phenotypes that each have specific advantages.
In diversifying or disruptive selection, average or intermediate phenotypes are often less fit than either extreme phenotype and are unlikely to feature prominently in a population.

Question 20

Genetic drift

Answer 20

Change in small population that later had a great impact on the phenotype of a species.

Question 21

Gene flow

Answer 21

Transfer of alleles/genes from one population to another.

Question 22

Genetic bottleneck

Answer 22

Sharp reduction in the size of a population due to environmental events.

Question 23

Convergent evolution

Answer 23

Organisms not closely related independently evolve similar traits.

Question 24

Allopatric speciation

Answer 24

Speciation that occurs when biological populations of the same species become isolated from each other to an extent that prevents or interferes with genetic interchange.

Question 25

Seeding

Answer 25

Adding specific species of bacteria and archaea to contaminated sites.

Question 26

Paraphyletic

Answer 26

Descended from a common evolutionary ancestor or ancestral group, but not including all the descendant groups.

Question 27

Polyphyletic

Answer 27

Derived from more than one common evolutionary ancestor or ancestral group and therefore not suitable for placing in the same taxon.

Question 28

Monophyletic

Answer 28

Descended from a common evolutionary ancestor or ancestral group, especially one not shared with any other group.

Question 29

Inbreeding depression

Answer 29

decline in average fitness that takes place when homozygosity increases and heterozygosity decreases in a population