population evolution

Question 1

gene pool

Answer 1

all alleles available for all traits

Question 2

changing gene frequency

Answer 2

alleles may become more or less common

Question 3

natural selection drives evolution by

Answer 3

selecting the most fit individuals

Question 4

evolution happens to ____, not ____.

Answer 4

populations, not individuals

Question 5

2 ways of measuring genetic variation

Answer 5

• % of genes that are heterozygous
• Nucleotide differences between individuals (many may be neutral)

Question 6

genetic variation: 4 sources

Answer 6

• making new alleles via mutations
• +/-/rearranging genes
  *rapid reproduction
  *sexual reproduction

Question 7

mutations are almost always

Answer 7

bad

Question 8

when would a mutation be neutral?

Answer 8

protein instructions are identical or similar OR change is in noncoding DNA

Question 9

how does rapid reproduction lead to more genetic variation?

Answer 9

rapid reproduction means inter-generation mutations are more common

Question 10

how does sexual reproduction lead to more genetic diversity?

Answer 10

it combines traits in new ways

Question 11

genetic diversity:

Answer 11

how many alleles are in a population

Question 12

population with HIGH genetic diversity:

Answer 12

-many genes have more than 1 version
-many gene combinations for new individuals

Question 13

population with LOW genetic diversity:

Answer 13

-most genes have 1 version
-much fewer gene combinations for new individuals

Question 14

natural selection requires …

Answer 14

genetic diversity

Question 15

fixed allele

Answer 15

single version of gene in entire population

Question 16

allele frequency

Answer 16

how common an allele is in a population

Question 17

hardy Weinberg equilibrium tests if

Answer 17

natural selection is happening or not

Question 18

hardy Weinberg equilibrium predicts

Answer 18

frequency of genotypes in the next generation. at equilibrium, genotype frequency does NOT change.

Question 19

Hardy Weinberg equilibrium assumes:

Answer 19

-no new alleles (mutations)
-random mating
-no natural selection
no genetic drift (large population)
-no gene flow (no individuals leave or enter)

*NO equilibrium if one of these is untrue

Question 20

Hardy Weinberg equilibrium is not met if

Answer 20

allele frequencies change

Question 21

most common reasons allele frequency changes:

Answer 21

-genetic drift
-gene flow
-natural selection

Question 22

genetic drift:

Answer 22

RANDOM CHANCE INFLUENCES ALLELE FREQUENCY

Question 23

genetic drift (change in allele frequency due to random chance) can lead to:

Answer 23

-rapid changes in allele frequency/traits
-permanent loss of alleles in population
-cause harmful alleles to become fixed in population

Question 24

genetic drift is most common in 3 situations

Answer 24

-founder effect
-bottleneck effect
-small population

Question 25

founder effect:

Answer 25

gene pool of immigrants to new area does not match gene pool of source population (can cause rare genetic diseases)

Question 26

bottleneck effect

Answer 26

gene pool of survivors after a disaster does not match the gene pool of the population before the disaster

Question 27

example of bottleneck effect

Answer 27

nearly all cheetahs died, forcing closely related cheetahs to breed. Current cheetah population has a small gene pool
 Increased diseases, poor sperm quality, high mortality

Question 28

small population:

Answer 28

The failure of one individual to reproduce can dramatically change the gene pool of a small population

Question 29

relative fitness

Answer 29

contribution to the next generation compared to others contribution

Question 30

3 steps to confirm/test natural selection

Answer 30

• artificial selection
  -natural selection in the lab
  -natural selection in the wild

Question 31

the modern synthesis

Answer 31

term for combination of evolution and genetics that started in the 30s

Question 32

___ provided a basis for understanding how natural selection worked

Answer 32

genetics

Question 33

natural selection favors mutations that give more ___

Answer 33

fitness

Question 34

well adapted individuals contribute more ___ to next generation

Answer 34

offspring (unfavorable traits then decrease)

Question 35

3 patterns of natural selection

Answer 35

• Stabilizing selection
• Directional selection
• Disruptive selection

Question 36

stabilizing selection

Answer 36

average variant in a population has the highest fitness

Question 37

stabilizing selection prevents …

Answer 37

a trait from changing in a population

Question 38

direction selection causes

Answer 38

population traits to move in a specific direction

Question 39

directional selection: one of the two extremes…

Answer 39

becomes more common

Question 40

disruptive selection

Answer 40

most common variant has lowest fitness

Question 41

disruptive selection leads to

Answer 41

a population with 2+ variants

Question 42

stabilizing selection, direction selection, disruptive selection: which is most likely to form a new species?

Answer 42

disruptive selection (leads to a population with 2+ variants)

Question 43

coevolution is when 2 species …

Answer 43

apply pressure on each other

Question 44

coevolution often occurs in

Answer 44

predator-prey relationships
-deer are fast to escape wolf, so wolf has to get faster or else they starve, and then deer gets faster, etc

Question 45

why don’t suboptimal alleles disappear?

Answer 45

balancing selection: natural selection favors maintaining multiple alleles in some circumstances

Question 46

frequency dependent selection

Answer 46

fitness of allele depends on how common it is (being common reduces allele fitness)

Question 47

heterozygous advantage?

Answer 47

some heterozygotes have higher fitness than homozygotes

Question 48

why did Dodo go extinct?

Answer 48

mismatched adaptation

Question 49

why is there a lot of concern with climate change occurring so rapidly?

Answer 49

adaptation takes time (many generations, not on lifetime)