8. Evolution by Natural Selection

Question 1

What is the defintion of natural selection?

Answer 1

interaction between organisms and their environment that causes differental reproduction of different phenotypes and thereby alters the gene pool of a population

Question 2

What is the definition of fitness?

Answer 2

how successful an animal is in passing on its alleles to future generations

Question 3

What are the two sources of genetic variation in a population?

Answer 3

new alleles
new combinations of existing alleles

Question 4

What are the six modes of natural selection?

Answer 4

directional selection
divergent selection
stabilizing selection
artificial selection
sexual selection
kin selection

Question 5

What is directional selection?

Answer 5

removing individuals at one extreme shifting the population average in the other direction

Question 6

What is divergent selection?

Answer 6

removing individuals from the average of the bell curve leading to new species

Question 7

What is stabilizing selection?

Answer 7

both extremes of a trait are selected against driving the population closer to the average

Question 8

What is artifical selection?

Answer 8

used to achieve desired traits through controlled mating

Question 9

What is sexual selection?

Answer 9

when mates do not choose randomly

Question 10

What is kin selection?

Answer 10

animals that live socially often share their alleles with other individuals and will sacrifice themselves for the sake of the alleles they share