evolution and adaptation

Question 1

deoxyribonucleic acid

Answer 1

molecule composed of two strands of nucleotides wound together in a double helix

Question 2

4 nucleotides

Answer 2

Adenine, Guanine, Thymine, and Cytosine

Question 3

chromosomes

Answer 3

compact structure containing DNA wound around proteins

Question 4

gene

Answer 4

sequence of DNA that codes for a particular protein (influences traits)

Question 5

alleles

Answer 5

alternate forms of a particular gene

Question 6

gene pool

Answer 6

all genes/alleles in a population

Question 7

polygenic

Answer 7

influenced by multiple genes

Question 8

pleiotropy

Answer 8

when a single gene affects multiple traits

Question 9

epistasis

Answer 9

when the expression of one gene is controlled by another gene

Question 10

heterozygous

Answer 10

when an individual has two different alleles at a gene

Question 11

homozygous

Answer 11

when an individual has two identical alleles at a gene

Question 12

codominant

Answer 12

when two alleles both contribute to a phenotype (pink flower)

Question 13

dominant

Answer 13

an allele that masks the expression of the other allele of a given gene (red flower)

Question 14

recessive

Answer 14

an allele whose expression is masked by the presence of another allele (white flower)

Question 15

random assortment

Answer 15

the process of making haploid gametes in which the combination of alleles that are placed into a given gamete could be any of those possessed by the diploid parent

Question 16

recombination

Answer 16

the reshuffling of genes that can occur as DNA is copied during meiosis and chromosomes exchange genetic material

Question 17

mutation

Answer 17

a random change in the sequence of nucleotides in regions of DNA that either comprise a gene or control the expression of a gene
-can be silent with no detectable effects
-can affect appearance or physiology
-can be lethal

Question 18

genetic drift

Answer 18

a process that occurs when genetic variation is lost because of random variation in mating, mortality, fecundity, and inheritance

Question 19

bottleneck effects

Answer 19

a reduction of genetic diversity in a population due to a large reduction in population size

Question 20

founder effect

Answer 20

when a small number of individuals leave a large population to colonize a new area and bring with them only a small amount of genetic variation

Question 21

selection

Answer 21

the process by which certain phenotypes are favored to survive and reproduce over other phenotypes

Question 22

stabilizing selection

Answer 22

when individuals with intermediate phenotypes have higher survival and reproductive success than those with extreme phenotypes

Question 23

directional selection

Answer 23

when individuals with an extreme phenotype experience higher fitness than the average phenotype of the population

Question 24

disruptive selection

Answer 24

when individuals with either extreme phenotype experience higher fitness than individuals with an intermediate phenotype

Question 25

strength of selection

Answer 25

difference between the mean of the phenotypic distribution before selection and the mean after selection -measured in units of standard deviation

Question 26

heritability

Answer 26

the proportion of the total phenotypic variation that is caused by genetic variation

Question 27

artificial selection

Answer 27

selection in which humans decide which individuals will breed and the breeding is done with a preconceived goal for the traits of the population

Question 28

natural selection

Answer 28

individuals interact with their environment, and traits that lead to greater fitness in an environment are passed on

Question 29

speciation

Answer 29

the evolution of new species

Question 30

phylogenetic trees

Answer 30

hypothesized patterns of relatedness among different ground such as populations, species, or genera -depict which groups evolved from other groups

Question 31

allopatric speciation

Answer 31

geographic isolation leads to genetic isolation

Question 32

divergence hypothesis

Answer 32

closely related species should be found on adjacent islands and sequence of branching events should correspond to island formation

Question 33

sympatric speciation

Answer 33

reproductive isolation without geographic isolation

Question 34

polyploidy

Answer 34

changes in chromosome numbers isolate populations genetically -particularly relevant in plants

Question 35

migration

Answer 35

movement of individuals between populations

Question 36

gene flow

Answer 36

movement of alleles between populations via immigration/emigration

Question 37

genotype

Answer 37

set of alleles that an individual bears

Question 38

positive assortative mating

Answer 38

mating of like with like partners -increases the proportion of homozygotes

Question 39

negative assortative mating

Answer 39

mating with unlike partners -increases the proportion of heterozygotes in a population

Question 40

selfing

Answer 40

extreme inbreeding -mating with oneself or an identical genotype