Lecture 8- Evolutionary Mechanisms

Question 1

polygenic inheritance

Answer 1

multiple genes independently affect a single character (Ex. Height)

Question 2

Pleiotropy

Answer 2

the ability of a single gene to have multiple effects

Question 3

Genetic drift

Answer 3

chance events cause allele frequencies to fluctuate unpredictably

Question 4

genetic drift is caused by

Answer 4

chance events associated with survival and reproduction

Question 5

in genetic drift, the smaller the sample:

Answer 5

the greater the chance of random deviation from a predicted result

Question 6

difference between natural selection and genetic drift is

Answer 6

natural selection is based on optimal phenotypes and evolution is carried out based on that while genetic drift is random

Question 7

can genetic drift be predicted?

Answer 7

no, it’s random

Question 8

founder effect

Answer 8

when a few individuals become isolated from the larger population, the new population’s gene pool will differ from the source population

Question 9

Bottleneck effect

Answer 9

sudden change in the environment drastically reduces the size of the population

Question 10

Are bottleneck effect and founder effect examples of genetic drift?

Answer 10

no, but they can RESULT in genetic drift

Question 11

Genetic drift can limit the ability of a population to

Answer 11

adapt

Question 12

adaptation definition

Answer 12

a feature that arose and was favored by natural selection for its current function

Question 13

Gene flow

Answer 13

the movement of alleles among populations

Question 14

alleles can be transferred through the movement of

Answer 14

fertile individuals or gametes

Question 15

gene flow tends to reduce

Answer 15

variation among populations over time

Question 16

Gene flow can also increase a population’s

Answer 16

fitness

Question 17

What is the only mechanism that consistently causes adaptive evolution

Answer 17

natural selection

Question 18

Adaptive evolution

Answer 18

traits that enhance survival or reproduction tend to increase in frequency over time.

Question 19

The ways natural selection can alter the frequency distribution of heritable traits

Answer 19

directional selection
disruptive selection
stabilizing selection

Question 20

Directional selection

Answer 20

conditions favor individuals at one extreme of a phenotypic range

Question 21

disruptive selection

Answer 21

conditions favor individuals at both extremes of the phenotypic range over the intermediate phenotypes

Question 22

stabilizing selection

Answer 22

conditions favor intermediate phenotypes over both extremes