Biology Chapter 22-23

Front 1

Adaptations are ______________ characteristics of organisms that enhance their __________ and _________ in specific environments.

Back 1

Adaptations are inherited characteristics of organisms that enhance their survival and reproduction in specific environments.

Front 2

Natural selection is a process by which individuals with better ____________ survive and ____________ more because of those traits.

Back 2

Natural selection is a process by which individuals with better adaptations survive and reproduce more because of those traits.

Front 3

Uniformitarianism

Back 3

the idea that geologic processes occur today in much the same way as they did in the past

Front 4

State Darwin's four postulates:

1.

2.

3.

4.

Back 4

1. Individual organisms that make up a population vary in traits.

2. Some trait differences are heritable.

3. Some individuals reproduce more than others, and only a subset of offspring will survive long enough to reproduce.

4. Individuals with certain traits are more likely to produce a greater number of offspring.

Front 5

The original source of all genetic variation is ______________.

Back 5

The original source of all genetic variation is mutation.

Front 6

Sexual reproduction (does/does not) change the frequency of alleles in the gene pool.

Back 6

Sexual reproduction does not change the frequency of alleles in the gene pool.

Front 7

Hardy-Weinberg Equation

Back 7

for a locus with two alleles, the proportion of homozygous dominant (p^2), heterozygous (2pq), and homozygous recessive (q^2) will have these proportions if the population is in equilibrium

Front 8

State the conditions for Hardy-Weinberg equilibrium.

Back 8

1. No mutations.

2. Random mating.

3. No natural selection.

4. Extremely large population size.

5. No gene flow.

Front 9

Genetic Drift

Back 9

process in which chance events cause unpredictable fluctionations in allele frequencies between generations

Front 10

Founder Effect

Back 10

genetic drift that occurs when a few individuals are isolated from a larger population and form a new population whose gene pool composition is not reflective of the original population

Front 11

Bottleneck Effect

Back 11

genetic drift that occurs when the size of a population is reduced (as by a natural disaster); typically, the surviving population is no longer genetically representative of the original population

Front 12

Genetic drift is significant in (large/small) populations.

Back 12

Genetic drift is significant in small populations.

Front 13

Genetic drift can cause allele frequencies to change (randomly/predictably).

Back 13

Genetic drift can cause allele frequencies to change randomly.

Front 14

Genetic drift can lead to a loss of ___________ within populations.

Back 14

Genetic drift can lead to a loss of genetic variation within populations.

Front 15

Genetic drift can cause harmful alleles to become ___________, meaning that it is the only allele for a certain locus in the gene pool.

Back 15

Genetic drift can cause harmful alleles to become fixed, meaning that it is the only allele for a certain locus in the gene pool.

Front 16

Gene Flow

Back 16

transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes

Front 17

Directional selection occurs when conditions favor individuals exhibiting (no/one/two) extreme(s) of a phenotypic range over the intermediate(s).

Back 17

Directional selection occurs when conditions favor individuals exhibiting one extreme of a phenotypic range over the intermediate(s).

Front 18

Disruptive selection occurs when conditions favor individuals exhibiting (no/one/two) extremes of a phenotypic range.

Back 18

Disruptive selection occurs when conditions favor individuals exhibiting two extremes of a phenotypic range.

Front 19

Stabilizing selection occurs when conditions favor individuals exhibiting (no/one/two) extremes of a phenotypic range.

Back 19

Stabilizing selection occurs when conditions favor individuals exhibiting no extremes of a phenotypic range.

Front 20

Generation-to-generation change in the allele frequencies in a population is called _________________.

Back 20

Generation-to-generation change in the allele frequencies in a population is called microevolution.

Front 21

Generation-to-generation change in the allele frequencies that is attributable to differential reproductive success in the face of environmental factors is called ____________.

Back 21

Generation-to-generation change in the allele frequencies that is attributable to differential reproductive success in the face of environmental factors is called natural selection.

Front 22

____________ is the only evolutionary force that consistently results in adaptation.

Back 22

Selection is the only evolutionary force that consistently results in adaptation.

Front 23

Heterozygote Advantage

Back 23

greater reproductive success of heterozygous individuals compared with homozygotes; tends to preserve genetic variation in a gene pool

Front 24

Balancing Selection

Back 24

natural selection that maintains two or more phenotypic forms in a population

Front 25

Sexual Dimorphism

Back 25

differences between secondary sex characteristics of males and females of the same species

Front 26

Sexual Selection

Back 26

form of natural selection in which individuals with certain inherited characteristics are more likely than others to obtain mates

Front 27

Intrasexual Selection

Back 27

form of natural selection in which there is direct competition among individuals of one sex for mates of the opposite sex

Front 28

Intersexual Selection

Back 28

form of natural selection in which individuals of one sex are choosy in selecting their mates from the other sex

Front 29

Frequency-Dependent Selection

Back 29

selection in which the fitness of a phenotype depends on how common the phenotype is in a population

Front 30

Point mutations in noncoding regions of DNA result in __________________.

Back 30

Point mutations in noncoding regions of DNA result in neutral variation.