Chapter 19

Question 1

loss of alleles within a population, purely by chance

Answer 1

genetic drift

Question 2

a reduction in genetic variation when a subset of population sets up a new colony

Answer 2

founders effect

Question 3

natural events get magnified-makes effect of genetic drift larger

Answer 3

bottleneck effect

Question 4

genetics

Answer 4

genotype

Question 5

what it looks like

Answer 5

phenotype

Question 6

phenotypes produced by combined effects of 2 or more genes

Answer 6

continuous variation

Question 7

what gives rise to genetic diversity among offspring?

Answer 7

random assortment of chromosomes, crossing over, random fertilization

Question 8

loss of chromosomes

Answer 8

deletions

Question 9

copy is made of chromosomes

Answer 9

duplications

Question 10

uneven crossing over of non-homologous chromosomes

Answer 10

chromosome translocations

Question 11

a group of interbreeding individuals in the same area, somewhat isolate from other groups

Answer 11

the population

Question 12

all the alleles of all the genes in a population

Answer 12

gene pool

Question 13

% of each genotype in the population

Answer 13

genotypic frequency

Question 14

% of each allele in the population

Answer 14

allelic frequency

Question 15

if a large population reproduces sexually at random, then the genetic frequencies should not change in the next generation and remains in equilibrium

Answer 15

hardy-weinberg equilibrium

Question 16

conditions for hardy-weinberg equilibrium

Answer 16

1. no mutations
2. mating is random
3. no selection (equal survival)
4. very large population size
5. no gene flow in or out (no immigration or emigration)

Question 17

an evolving population is one that is showing genetic change over generation

change in allele frequency over time

Answer 17

microevolution

Question 18

acts non-randomly on phenotypes of individuals, changes allelic and genotypic frequencies of populations non-randomly, always leads to adaptation of population to the current environment

Answer 18

natural selection

Question 19

genetic frequency changes due to random events, often occurs in small populations

outcomes: random changes in allele frequency in either direction, often reduces diversity, one allele may become fixed, all others lost

Answer 19

genetic drift

Question 20

alleles move in/out of the population

migration of adults, dispersal of gametes

Adds diversity to the population, reduces differences between populations, and increases survival under stressful conditions

Answer 20

gene flow

Question 21

fitness is relative to other individuals in the population

Fittest= best reproductive success

Answer 21

relative fitness

Question 22

shifts character’s mean value to one direction

Answer 22

directional selection

Question 23

intermediates are less fit than extremes, maintains diversity

Answer 23

disruptive selection

Question 24

intermediate types are more successful than the extreme, variation is reduced

Answer 24

stabilizing selection

Question 25

success based on traits related to obtaining mates (and not directly related to the environment)

Answer 25

sexual selection

Question 26

when girls and boys look different

ex: male cardinals are bright red to appeal to the females, which are brown in order to hide while laying eggs.

Answer 26

sexual dimorphism