Chapter 10 Definitions

Question 1

The process by which, as a result of natural selection, a population’s organisms become better matched to their environment. Also, a specific feature, such as the quills of a porcupine, that makes an organism more fit.

Answer 1

adaptation

Question 2

A special case of natural selection; the three necessary and sufficient conditions for natural selection are satisfied, but the differential reproductive success is determined by humans rather than by nature and so is typically goal-oriented.

Answer 2

artificial selection

Question 3

The study and interpretation of distribution patterns of living organisms around the world.

Answer 3

biogeography

Question 4

A phenomenon through which genetic drift can occur; a sudden reduction in population size (often due to famine, disease, or rapid environmental disturbance) that can lead to changes in the allele frequencies of a population.

Answer 4

bottleneck effect

Question 5

A process of natural selection in which features of organisms not closely related come to resemble each other as a consequence of similar selective forces.

Answer 5

convergent evolution

Question 6

The situation in which some individuals have greater reproductive success than other individuals in a population. Along with variation and heritability, it is one of the three conditions necessary for evolution by natural selection.

Answer 6

differential reproductive success

Question 7

Selection that, for a given trait, increases fitness at one extreme of the phenotype and reduces fitness at the other, leading to an increase or decrease in the mean value of the trait.

Answer 7

directional selection

Question 8

Selection that, for a given trait, increases fitness at both extremes of the phenotype distribution and reduces fitness at middle values.

Answer 8

disruptive selection

Question 9

A change in allele frequencies of a population.

Answer 9

evolution

Question 10

A relative measure of the reproductive output of an individual with a given phenotype compared with the reproductive output of individuals with alternative phenotypes.

Answer 10

fitness

Question 11

In genetics, the point at which the frequency of an allele in a population is 100%, and thus there is no more variation in the population for this gene.

Answer 11

fixation

Question 12

The remains of an organism, usually its hard parts such as shell, bones, or teeth, that have been naturally preserved; also, traces of such an organism, such as footprints.

Answer 12

fossil

Question 13

A phenomenon by which genetic drift can occur. The isolation of a small subgroup of a larger population can lead to changes in the allele frequencies of the isolated population, because all the descendants of the smaller group will reflect the allele frequencies of the subgroup, which may differ from those of the larger source population.

Answer 13

founder effect

Question 14

A change in the allele frequencies of a population due to movement of some individuals of a species from one population to another, changing the allele frequencies of the population they join; also known as migration.

Answer 14

gene flow

Question 15

A random change in allele frequencies over successive generations; a cause of evolution.

Answer 15

genetic drift

Question 16

The transmission of traits from parents to offspring via genetic information; also known as inheritance.

Answer 16

heritability

Question 17

Body structures in different organisms that, although they may have been modified over time to serve different functions in different species, are derived through inheritance from a common evolutionary ancestor.

Answer 17

homologous structure

Question 18

The transmission of traits from parents to offspring via genetic information; also known as heritability.

Answer 18

inheritance

Question 19

In populations, a change in allele frequencies due to the movement of some individuals from one population to another; an agent of evolutionary change caused by the movement of individuals into or out of a population.

Answer 19

migration

Question 20

An alteration in the base-pair sequence of an individual’s DNA; may arise spontaneously or following exposure to a mutagen.

Answer 20

mutation

Question 21

A mechanism of evolution that occurs when, for a heritable variation of a trait, individuals with one version of the trait have greater reproductive success than individuals with a different version of that trait.

Answer 21

natural selection

Question 22

A group of organisms of the same species living in a particular geographic region.

Answer 22

population

Question 23

A method of determining both the relative and the absolute ages of objects such as fossils by measuring both the radioactive isotopes they contain, which are known to decay at a constant rate, and their decay products.

Answer 23

radiometric dating

Question 24

The process by which natural selection favors traits, such as ornaments or fighting behavior, that give an advantage to individuals of one sex in attracting mating partners.

Answer 24

sexual selection

Question 25

Selection that, for a given trait, produces the greatest fitness at the intermediate point of the phenotypic range.

Answer 25

stabilizing selection

Question 26

Any characteristic or feature of an organism, such as red petal color in a flower.

Answer 26

trait

Question 27

A structure that was once useful to the organism but has lost its function over evolutionary time; an example is molars in bats that now consume an exclusively liquid diet.

Answer 27

vestigial structure