Chapter 18 Vocab (Evolution)

Question 1

Allele*

Answer 1

one of a number of different forms of a gene

Question 2

Allele Frequency *

Answer 2

the number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene (percentage/probability)

Question 3

Behavioral Isolation

Answer 3

form of a reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding

Question 4

Directional Selection*

Answer 4

form of natural selection when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

Question 5

Disruptive Selection *

Answer 5

natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve

Question 6

Genetic Drift*

Answer 6

random change in allele frequency caused by a series of chance occurrences that cause an allele to become more or less common in a population

Question 7

Genetic Equilibrium *

Answer 7

situation in which allele frequencies in a population remain the same

Question 8

Geographic Isolation

Answer 8

form of reproductive isolation when two populations are separated by geographical barriers such as river, mountains, or bodies of water, leading to the formation of two different species

Question 9

Gene Pool

Answer 9

all the genes, including all the different alleles for each gene, that are present in a population at any time

Question 10

Hardy-Weinberg Principle

Answer 10

states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change

Question 11

Migration*

Answer 11

pattern of behavior in which animals travel from one habitat to another in search of food, better conditions, or reproductive needs

Question 12

Reproductive Isolation

Answer 12

isolation of a species or population so that they no longer interbreed and evolve into two separate species

Question 13

Sexual Selection*

Answer 13

when individuals select mates based on heritable traits (looks)

Question 14

Speciation*

Answer 14

formation of a new species

Question 15

Stabilizing Selection*

Answer 15

form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve