Adaptation & Speciation

Question 1

Biological Species Concept

Answer 1

holds that species are groups of actually (or potentially) interbreeding natural populations that are reproductively isolated from other such groups

Question 2

Metapopulation

Answer 2

a group of spatially separated populations of the same species that interact at some level (for example, exchange alleles)

Question 3

General Lineage Species

Answer 3

the idea that species are metapopulations of organisms that exchange alleles frequently enough that they comprise the same gene pool and therefore the same evolutionary lineage

Question 4

isolating barrier

Answer 4

refers to an aspect of the environment, genetics, behavior, physiology, or ecology of a species that reduces or impedes gene flow from individuals of other species. Isolating barriers can be geographic or reproductive

Question 5

Speciation

Answer 5

the evolutionary process by which new species arise. Speciation causes one evolutionary lineage to split into two or more lineages (cladogenesis)

Question 6

Allopatric

Answer 6

when populations are in separate, nonoverlapping geographic areas (that is, they are separated by geographic barriers to gene flow)

Question 7

Sympatric

Answer 7

when populations are in the same geographic area; the evolution of new species within a contiguous population that still has extensive gene flow

Question 8

Parapatric

Answer 8

the evolution of new species within a spatially extended population that still has some gene flow

Question 9

Peripatric

Answer 9

occurs when a small population of a species becomes isolated from the main population and undergoes evolutionary changes that lead to the formation of a new species. In peripatric speciation, the isolated population is typically located on the periphery of the species’ range, hence the term “peripatric,” which means “occurring on the periphery” or “at the edge.”

Question 10

reproductive isolation

Answer 10

when reproductive barriers prevent or strongly limit reproduction between populations. The result is that few or no genes are exchanged between the populations

Question 11

gametic incompatibility

Answer 11

occurs when sperm or pollen from one species fails to penetrate and fertilize the egg or ovule of another species

Question 12

prezygotic reproductive barriers

Answer 12

an aspect of the genetics, behavior, physiology, or ecology of a species that prevents sperm from one species from fertilizing eggs of another species. Prezygotic barriers reduce the likelihood that a zygote will form

Question 13

postzygotic reproductive barriers

Answer 13

an aspect of the genetics, behavior, physiology, or ecology of a species that prevents hybrid zygotes from successfully developing and reproducing themselves

Question 14

all bolded terms in Figure 13.7

Question 15

Reinforcement

Answer 15

the increase of reproductive isolation between populations through selection against hybrid offspring

Question 16

Fusion

Question 17

primary hybrid zone

Question 18

secondary hybrid zone

Question 19

selection differential

Answer 19

(S) is a measure of the strength of phenotypic selection. The selection differential describes the difference between the mean of the reproducing members of the population that contribute offspring to the next generation and the mean of all members of a population

Question 20

response to selection

Answer 20

the changes in a population’s traits or characteristics over generations due to natural selection or artificial selection pressures

Question 21

Heritability

Answer 21

The degree to which phenotypes are determined by individual genes transmitted from parents, rather than by interactions between different genes or between alleles of the same genes

Question 22

directional selection

Answer 22

Selection in which phenotypes at one extreme of the population distribution are favored. (Contrast with disruptive selection, stabilizing selection.); favors individuals on one end of the distribution of phenotypes present in a population

Question 23

stabilizing selection

Answer 23

Selection against the extreme phenotypes in a population, so that the intermediate types are favored. (Contrast with directional selection, disruptive selection.); favors individuals in the middle of the distribution of phenotypes present in a population (for example, by acting against individuals at either extreme)

Question 24

selection coefficient

Answer 24

Selection in which phenotypes at both extremes of the population distribution are favored. (Contrast with directional selection, stabilizing selection.); favors individuals at the tails of the distribution of phenotypes present in a population (for example, by acting against individuals with intermediate trait values)

Question 25

Life history trait

Answer 25

the pattern of investment an organism makes in growth and reproduction. Life history traits include an organism’s age at first reproduction, the duration and schedule of reproduction, the number and size of offspring produced, and life span

Question 26

inclusive fitness

Answer 26

describes an individual’s combined fitness, including its own reproduction as well as any increase in the reproduction of its relatives due specifically to its own actions

Question 27

direct fitness

Question 28

indirect fitness

Question 29

antagonistic pleiotropy

Answer 29

the condition that occurs when a mutation with beneficial effects for one trait also causes detrimental effects on other traits

Question 30

Senescence

Answer 30

the deterioration in the biological functions of an organism as it ages

Question 31

kin selection

Answer 31

selection arising from the indirect fitness benefits of helping relatives

Question 32

Hamilton’s rule

Answer 32

supports the notion that natural selection favours genetic success, not reproductive success

Question 33

R = relatedness coefficient

Question 34

C = cost to donor

Question 35

B = benefit to recipient