Exercise 10

Question 1

If all conditions of Hardy Weinberg equilibrium are met

Answer 1

Allele frequencies stay the same

Question 2

if a population is in Hardy Weinberg equilibrium and p equals .6

Answer 2

q equals .4

Question 3

Natural selection operates directly on

Answer 3

The phenotype

Question 4

The process that discriminates between phenotypes with respect to their ability to produce offspring is known as

Answer 4

Natural selection

Question 5

Two populations that have no gene flow between them are more likely to

Answer 5

Become different with time

Question 6

The process that results in individuals of two populations losing the ability to interbreed is referred to as

Answer 6

Speciation

Question 7

Two ways in which new alleles can become incorporated in a population are

Answer 7

Mutation and gene flow

Question 8

If a new allele appears in a population, the Hardy Weinberg formula

Answer 8

Can be expanded by adding more terms

Question 9

A shift from the expected allele frequencies, resulting from chance, is known as

Answer 9

Genetic drift

Question 10

Genetic drift is a process that has a greater effect on populations that

Answer 10

Are small

Question 11

What effect does increasing gene flow between two populations have on their genetic makeup?

Answer 11

Increasing gene flow tends to result in two populations becoming increasingly similar from a genetic standpoint

Question 12

How can selection cause two populations to become different with time?

Answer 12

Selection can cause two populations to become different with time in that the selection pressures on the two populations will likely be different. That is, the two populations may experience different predators, competitors, weather patterns, parasites, disease etc. Thus, The two populations will evolve in different directions

Question 13

Describe how the effects of directional selection can be offset by gene flow

Answer 13

Gene flow brings variation back into the population that may counter directional selection. Directional selection is selection for one phenotype. Gene flow should bring in new alleles that enhances the preservation perhaps one of the other phenotypes

Question 14

In addition to mutation, what other mechanism allows for new genetic information to be introduced into a population? Explain your answer

Answer 14

Gene flow allows for genetic information to be introduced into a population (in addition to mutation)

Question 15

What is the fate of most new mutations?

Answer 15

Most new mutations do not end up expressing themselves at all in the phenotypes. They have no effect usually

Question 16

If a population has three codominant color alleles, how many phenotypes are possible?

Answer 16

six phenotypes

Question 17

What effects can nonrandom mating exert on a population?

Answer 17

Nonrandom meeting will tend to reduce variation in the population over time

Question 18

What two evolutionary agents are most responsible for decreases in genetic variation in a population?

Answer 18

Genetic drift (founder effect, bottleneck effect) and nonrandom meeting

Question 19

If a population has three color alleles and one is dominant over the other two, how many phenotype are possible?

Answer 19

Four

Question 20

In humans, birth weight is an example of a characteristic affected by stabilizing selection. What does this mean to the long-term average birthweight of human babies? How might the increasing number of Caesarean sections be affecting this characteristic?

Answer 20

Caesarean sections may result in a shift of human birth weights - to an average heavier weight (directional selection) since larger babies can be born via C-sections