16.2

Question 1

What is a mutation?

Answer 1

Spontantious musations occur constantly at a very low rate. If an organism is exposed to mutagens, rates can increase. Musations can affect genetic equilibrium by producing new alleles for a trait.

Question 2

What is migration?

Answer 2

The second part of the genetic equilibrium is that populations remain constant. Organisms moving in and out of areas.

Question 3

What is immigration?

Answer 3

movement of individuals into a population

Question 4

What is emmigration?

Answer 4

movement of individuals out of a population

Question 5

What is gene flow?

Answer 5

process of genes moving from one population to another

Question 6

What is genetic drift?

Answer 6

Phenomenon by which allele frequencies in a population change as a result of random events or chance. Small populations-large degree of genetic drift. Large populations-small degree of genetic drift.

Question 7

What is non-random mating?

Answer 7

Mating without regard to genetic makeup. Many mating that are non random and have some degree of kinship (influenced by geographical proximity) can result in disordes. Ex. individuals may often select a mate with similiar physical characteristics.

Question 8

What is assertive mating? What does it affect and not affect?

Answer 8

selection of mate based oncharacteristics

affect genotypes-not allele frequency

Question 9

What is stabilizing selection?

Answer 9

Individuals with average form of a trait have higher fitness. Average represents the optimum for most traits; extreme forms of most traits confer lower fitness on the individuals that have them

Question 10

What is the most common kind of selection?

Answer 10

stabilizing selection

Question 11

What does stabilizing selection operate on/

Answer 11

most traits and results in very similar morphology between members of a species

Question 12

What is directional selection?

Answer 12

Individuals that display a more extremem form of a trait have greater fitness than individuals with an average form of a trait away. Away from average and toward one extreme. Think tongue length of ant eaters. Area with termites that build deep nests. Long tongues woudl more affectively prey on the termites.

Question 13

What is disruptive selection?

Answer 13

Individuals with either extreme vatiation of a trait have greater fitness than individuals with the average form of the trait. For example, limpet shell colour varies from pure white to dark tan. White shelled llimpets that are on rocks covered with barmacles (also white) are at an advantage becasuse birds have a hard time distinguishing thelimpets from the barnacles. On dark coloured rock, dark limpets are at an advantage. However, the birds easily spot limpets with shells of intermediate colours which are visible on both dark and light backgrounds.

Question 14

What is sexual selection?

Answer 14

In many bird species, the males are brightly coloured and easy for predators to see. Females tend to choose the males they mate with based on certain traits. A male must be selected by a female, and their extreme traits give the female an indication of the males gene quality. While survival to reproductive maturity is necessary, survival alone is not enough to further evolution. The genes of successful reproducers, rather than those of merly successful survivors are amplified through natural selection.
The tendency of males to develop extreme forms of traits that appeal to females is a result of sexual selection.

Question 15

What is genetic drift?

Answer 15

When allele frequences in a population change as a result of random events of chance.

Question 16

How does mutation disrupt the genetic equilibrim? How does Immigrantion disrupt the genetic equilibrium?

Answer 16

By producing new alleles for a trait, because many mutations are harmful. Immigration can affect the genetic equilibrium because it requires that the population remain constant and the movement of individuals into a populationcan change gene frequencies because they have different alleles and allele frequencies.

Question 17

What are the five violations of the conditions necessary for the Hardy-Weinberg Genetic Equilibrium that can cause evolution to occur?

Answer 17

mutation, migration, genetic drift, non random mating, and natural selection

Question 18

Human newborns with either a very high or a very low birth weight are more likely to die in infancy. What type of selection does this seem to be?

Answer 18

This would most likely be stabilizing selection because they are the extremem forms of a trait, not the average, which in this kind of selection have higher fitness.