Microevolution

Question 1

Hardy-Weinberg Principle

Answer 1

both allele and genotype frequencies in a population remain constant

they are in equilibrium from generation to generation

equilibrium remains that way unless specific disturbing influences are introduced (microevolution)

Question 2

Microevolution

Answer 2

change in allele frequency within a population

small time frame (over generations)

due to four different processes: mutation, gene flow (migration), non-random mating, genetic drift and selection (natural and artificial)

Question 3

Macroevolution

Answer 3

a scale of analysis of evolution in a separated gene pools

change that occurs at or above the level of species

large time frame, millions of years

Question 4

Mutation

Answer 4

change that occurs in the DNA of an individual

Question 5

heritable Mutation has…

Answer 5

the potential to affect entire gene pool

Question 6

beneficial mutations provide…

Answer 6

selective advantage

Question 7

example of mutation

Answer 7

1950s Warfarin (poison) resistance in Norway rat spread through Europe

Question 8

Gene flow (migration)

Answer 8

the net flow of alleles from one population to another due to the migration of individuals

Question 9

example of gene flow

Answer 9

gene flow between grey wolf populations, individuals travel long distances

Question 10

gene flow can increase…

Answer 10

genetic diversity of a population

Question 11

Non- random mating

Answer 11

mating among individuals on the basis of mate selection for a particular phenotype

Question 12

Genetic Drift

Answer 12

change in frequencies of alleles due to chance events in a small breeding population

Question 13

genetic drift

Phenotypic probabilities are…

Answer 13

amplified in small populations (ie. 75% of 4 individuals = 3/4, 75% of 1000 individuals =750/1000)

Question 14

genetic drift

allele frequencies…

Answer 14

shift in the second and third generations

Question 15

genetic drift

reduces variation because…

Answer 15

alleles are lost (“drifted” out of the population)

Question 16

Founder effect

Answer 16

change in a gene pool that occurs when a few individuals start a new isolated population

Question 17

example of founder effect

Answer 17

strong winds carry a pregnant fruit fly to a previously unpopulated island

Question 18

founder effect has…

Answer 18

limited gene pool

Question 19

another example of founder effect showing limited gene pool

Answer 19

Polydactylism in amish populations in Philadelphia ( was founded in 1700 by a few families )

Question 20

Bottleneck effect

Answer 20

changes in gene distribution that result from a rapid decrease in population size

Question 21

what can cause rapid decrease in population?

bottleneck effect

Answer 21

starvation, disease, human activities, and natural disasters

Question 22

example of bottleneck effect

Answer 22

1775 Pingelap Island Typhoon, 30 of 1600 survived, 10% of current population have a colour vision deficiency which is way less prevalent in general population

Question 23

stabilizing selection

Answer 23

favours intermediate phenotypes and acts against extreme variants

Question 24

stabilizing selection improves…

Answer 24

adaptation of the population to constant aspects of environment

Question 25

directional selection

Answer 25

favours the phenotypes at one extreme over another, resulting in the distribution curve of phenotypes shifting in the direction of that extreme

Question 26

example of directional selection

Answer 26

peppered moths, anti-biotic resistance

Question 27

disruptive selection

Answer 27

favours the extremes of a range of a phenotypes rather than intermediates

Question 28

disruptive selection can result…

Answer 28

in the elimination of intermediate phenotypes

Question 29

example of disruptive selection

Answer 29

sexual selection for large and small salmon (dominate and “sneaking”)