Chapter 14 How Populations Evolve

Question 1

Adaptation

Answer 1

A trait that increases the ability of an individual to survive and reproduce compared to individuals without the trait.

Question 2

Adaptive Radiation

Answer 2

The rise of many new species in a relatively short time as a result of a single species that invades different habitats and evolves under different enviromental pressures in those habitats.

Question 3

Allele Frequency

Answer 3

For any given gene, the relative proportion of each allele of that gene in a population.

Question 4

Coevolution

Answer 4

The evolution of adaptations in two species due to their extensive interactions with one another, in which each species is a source of natural selection on the other.

Question 5

Competition

Answer 5

Interaction among individuals who attempt to use a resource (for example, food or space) that is limited relative to the demand for it.

Question 6

Equilibrium Population

Answer 6

A population in which allele frequencies and the distribution of genotypes do not change from generation to generation.

Question 7

Extinction

Answer 7

The death of all members of a species.

Question 8

Fitness

Answer 8

The reproductive success of an oganism, usually expressed in relation to the average reproductive success of all individuals in the same population.

Question 9

Founder Effect

Answer 9

The result of an event in which an isolated population is founded by a small number of individuals; may result in genetic drift if allele frequencies in the founder population are by chance different from those parent population.

Question 10

Gene Flow

Answer 10

The movement of alleles from one poluation to another owing to the movement of individual oganisms of their gametes.

Question 11

Gene Pool

Answer 11

The total of all alleles of all genes in a population; for a single gene, the total of all the alleles of that gene that occur in a population.

Question 12

Genetic Drift

Answer 12

A change in the allele frequencies of a population hat occurs purely by chance.

Question 13

Hardy-Weinberg principle

Answer 13

A mathematical model proposing that, under certain conditions, the allele frequencies and genotype frequencies in a sexually reproducing population will remain constant over generations.

Question 14

Isolating Mechanism

Answer 14

A morphological, physiological, behavioral, or ecological difference that prevents members of two species from interbreeding.

Question 15

Mutation

Answer 15

A change in the base sequence of DNA in a gene; normally refers to genetic change significant enough to alter the appearance or functions of the organism.

Question 16

Natural Selection

Answer 16

The process in which unequal survival and reproduction of organisms, favoring individuals with particular traits, causes those traits to become increasingly common in a population.

Question 17

Population

Answer 17

All the members of a species that occupy a particular area at the same time.

Question 18

Population Bottleneck

Answer 18

The result of an event that causes a population to become extremely small; may cause genetic drift that results in changd allele frequencies and loss of genetic variability.

Question 19

Postmating Isolating Mechanism

Answer 19

Any structure, physiological function, or developmental abnormality that prevents organisms of two different populations, once mting has occured, from producing vigorous, ferile offspring.

Question 20

Predation

Answer 20

The act of eating another living organism.

Question 21

Premating Isolating Mechanism

Answer 21

Any structure, physiological function, or behavior that prevents organisms of two different populations from interbreeding.

Question 22

Reproductive Isolation

Answer 22

The failure of organisms of one poluation to breed successfully with members of another; may be due to premating or postmating isolating mechanisms.

Question 23

Sexual Selection

Answer 23

A form of reproduction in which genetic material from two parent organisms is combined in the offspring; normally, two haploid gametes fuse to form a diploid zygote.

Question 24

Speciation

Answer 24

The process of species formation, in which a single species splits into two or more species.

Question 25

Species

Answer 25

The basic unit of taxonomic classification, consisting of a group of poluations that evolves independently. In sexually reproducing organisms, a species can be defined as a population or series of populations of organisms that interbreed freely with one another under natural conditions but that do not interbreed with members of other species.