Chapter 23 The Evolution Of Populations

Question 0

Adaptation

Answer 0

Natural selection improves the match between an organism and environment

Question 1

Microevolution

Answer 1

Small scale, a change in allele frequencies in a population over generations

Question 2

Genetic variation

Answer 2

Diff among ind in the composition of their genes or other DNA sequences

Question 3

Mutation

Answer 3

A change in the nucleotide sequence of an organisms DNA

Question 4

Population

Answer 4

A group of ind of the same species that live in the same area and interbreed, producing fertile offspring

Question 6

Gene pool

Answer 6

Consists of all copies of every type of allele at every locus in all members of the pop

Question 7

Conditions for hardy weinberg =

Answer 7

no mutations, random mating, no natural selection, extremely large pop size, and no gene flow

Question 8

natural selectionq

Answer 8

individuals in a population exhibit variations in their heritbale traits and those with traits that are better suited to their environment tend to produce more offspring than those with traits that are not a well suited

Question 9

adaptive evolution

Answer 9

evolution that results in a better match between organisms and their environmnent

Question 10

genetic drift

Answer 10

chance events that can cause allele frequencies to fluctuate unpredictably from one generation to the next, especially in small pops

Question 11

the founder effect

Answer 11

when a few individuals become isolated from a large population, this smaller group may estabilish a new pop whose gene pool differs from the source pop

Question 12

the bottleneck effect

Answer 12

a suddne reduction in pop size due to a change in the environment

Question 13

gene flow

Answer 13

the transfer of alleles in to or out of a pop due to the movement of fertile ind or their gametes

Question 14

relative fitness

Answer 14

the contribution an ind makes to the gene pool of the next gen, relative to the contributions of other individuals.

Question 15

directional selection

Answer 15

favors on extreme of phenotype

Question 16

disruptive selection

Answer 16

favors both extremes of phenotypes

Question 17

stabilizing selsction

Answer 17

favors intermediate variants

Question 18

sexual selection

Answer 18

natural selection for mating success

Question 19

sexual dimorphism

Answer 19

marked diff between the sexes in secondary sexual characteristics

Question 20

intrasexual selection

Answer 20

within sex, in of one sex compete directly for mates of the opp sex, usually males

Question 21

intersexual selection

Answer 21

female choice, ind of one sex are choosy in selecting their mates from the other sex

Question 22

heterozygote advantage

Answer 22

hetero have increased fitness then do both homozygous

Question 23

frequency dependent selection

Answer 23

the fitness of the phenotype depends on how common it is in the pop, scale eating fish

Question 24

diploidy

Answer 24

maintains genetic variation in the form of hidden recessive alleles

Question 25

why natural selection cannot make perfect organisms

Answer 25

selection can act only on existing variations, evolution is limited by historical constraints, adaptations are often compromises, chance, nat sel, and enviro interact