Chapter 23 Vocab

Question 1

population genetics

Answer 1

investigative processes that cause changes in allele and genotype frequencies in populations

Question 2

gene pool

Answer 2

all the alleles of all the genes in a certain population

Question 3

inbreeding

Answer 3

mating between closely related individuals

Question 4

deleterious allele

Answer 4

alleles that decrease fitness

Question 5

inbreeding depression

Answer 5

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

Question 6

sexual selection

Answer 6

favors individuals with traits that increase their ability to obtain mates

Question 7

ecological selection

Answer 7

favors individuals with heritable traits that enhance their ability to survive and reproduce in certain physical and/or biological environment, excluding ability to obtain a mate

Question 8

genetic variation

Answer 8

number and relative frequency of alleles that are present in a particular population

Question 9

purifying selection

Answer 9

decreases frequency of, or even eliminates, deleterious alleles

Question 10

intersexual selection

Answer 10

between species, one sex is selecting the other sex for mating

Question 11

intrasexual selection

Answer 11

within a sex, competing among members of the same sex for mating

Question 12

territory

Answer 12

actively defended area where owner has exclusive or close to exclusive use

Question 13

sexual dimorphism

Answer 13

any trait that differs between male and female
- make and female usually look different

Question 14

sexual polymorphism

Answer 14

any trait that occurs in 2 or more forms among females and males in population

Question 15

genetic drift

Answer 15

change in allele frequencies in a population that is due to chance

Question 16

sampling error

Answer 16

selection of a nonrepresentative sample from some larger population, due to chance

Question 17

founder effect

Answer 17

change in allele frequencies that occurs when a new population is established from a small group of individuals due to sampling error

Question 18

bottleneck effect

Answer 18

if large population experiences sudden reduction in size

Question 19

genetic bottleneck

Answer 19

sudden reduction in diversity of alleles in population resulting from sudden decrease in size of population

Question 20

gene flow

Answer 20

movement of alleles between populations

Question 21

point mutation

Answer 21

change in a single base pair

Question 22

chromosome level mutation

Answer 22

change in number or composition of chromosomes

Question 23

lateral gene transfer

Answer 23

transfer of genetic information from one species to another, rather than from parent to offspring

Question 24

beneficial allele

Answer 24

allele from a mutation that allows individual to produce more offspring increase fitness

Question 25

neutral allele

Answer 25

allele from a mutation that has no effect on fitness

Question 26

Hardy-Weinberg principle

Answer 26

genotype frequencies in large population do not change from generation to generation in absence of evolutionary process and nonrandom mating

Question 27

what do the quantities mean for Hardy-Weinberg

Answer 27

p= frequency of A alleles
q= frequency of “a” alleles in same gene pool

Question 28

directional selection

Answer 28

• average phenotype of population changes in 1 direction
• shift
• tends to decrease genetic diversity

Question 29

stabilizing selection

Answer 29

genetic variation in population is reduced but there is no change in average value of a trait over time

Question 30

disruptive selection

Answer 30

• eliminates phenotypes near average value
• favors extreme phenotypes
• overall genetic variation is increased
• can play a role in speciation

Question 31

balancing selection

Answer 31

• no phenotype has distinct advantage
• heterozygous advantage
• frequency dependent selection

Question 32

heterozygous advantage

Answer 32

heterozygous individuals have increased fitness than homozygous

Question 33

frequency dependent selection

Answer 33

certain alleles are favored when they are rare, but not when they are common