Chapter 14

Question 1

Speciation

Answer 1

The process by which one species splits into two or more species.

Question 2

Biological Species Concept

Answer 2

Defines a species as a group of populations whose members have the potential to interbreed in nature and produce fertile offspring.

Question 3

Morphological Species Concept

Answer 3

Defines a species based on physical traits (Morph: form).

Question 4

Ecological Species Concept

Answer 4

Identifies species in terms of their ecological niches, focusing on unique adaptations to particular roles in a biological community.

Question 5

Phylogenetic Species Concept

Answer 5

Defines a species as the smallest group of individuals that share a common ancestor and thus form one branch on the tree of life.

Question 6

Prezygotic Barrier

Answer 6

Prevents mating or fertilization between species.

Question 7

Postzygotic Barrier

Answer 7

Operates after hybrid zygotes have formed.

Question 8

Habitat Isolation

Answer 8

Lack of opportunities to encounter each other. (land vs water snakes). (Prezygotic).

Question 9

Temporal Isolation

Answer 9

Breeding at different times or seasons. (Prezygotic).

Question 10

Behavioral Isolation

Answer 10

Failure to send or receive appropriate signals. Different courtship rituals. (Prezygotic)

Question 11

Mechanical Isolation

Answer 11

Physical incompatibility of reproductive parts. (Plants that can only be pollinated by long curved-bill humming birds vs short straight ones.) (Prezygotic).

Question 12

Gametic Isolation

Answer 12

Molecular incompatibility of eggs and sperm or pollen and stigma. (Prezygotic).

Question 13

Reduced Hybrid Viability

Answer 13

Interaction of parents genes impairs the hybrid’s development or survival. (some salamanders can hybridize but offspring are frail and won’t survive). (Postzygotic).

Question 14

Reduced Hybrid Fertility

Answer 14

Hybrids are vigorous but cannot produce viable offspring. (Horse x Donkey = Mule but it is sterile). (Postzygotic).

Question 15

Hybrid Breakdown

Answer 15

Hybrids are viable and fertile, but their offspring are feeble or sterile. (Hybrids of rice can produce a next gen rice plant but it is sterile). (Postzygotic).

Question 16

Allopatric Speciation

Answer 16

The formation of new species in populations that are geographically isolated from one another.

Question 17

Sympatric Speciation

Answer 17

The formation of a new species within the same geographic area as its parent species.

Question 18

Polyploid

Answer 18

A cell that has more than 2 complete sets of chromosomes.

Question 19

Adaptive Radiation

Answer 19

The evolution of many diverse species from a common ancestor.

Question 20

Hybrid Zones

Answer 20

Regions in which members of different species meet and mate, producing at least some hybrid offspring.

Question 21

Punctuated Equilibria

Answer 21

In the fossil record, long periods in which a species undergoes little or no morphological change (Equilibria) interrupted (punctuated) by relatively brief periods of sudden change.

Question 22

Punctuated Equilibria Model

Answer 22

States that species change the most as they arise from an ancestral species and then change relatively little for the rest of their existence.