Lesson 6: Ecology and Evolution

Question 1

A process of evolutionary change in which traits that confer survival or reproductive advantages tend to increase in frequency in a population over time.

Answer 1

adaptive evolution

Question 2

A process in which chance events determine which alleles are passed from one generation to the next, thereby causing allele frequencies to fluctuate randomly over time; the effects of genetic drift are most pronounced in small populations.

Answer 2

genetic drift

Question 3

The genetic makeup of an individual.

Answer 3

genotype

Question 4

An event in which a large proportion of Earth’s species are driven to extinction worldwide in a relatively short time.

Answer 4

mass extinction

Question 5

Change in the DNA of a gene.

Answer 5

mutation

Question 6

The process by which individuals with certain heritable characteristics tend to survive and reproduce more successfully than other individuals because of those characteristics.

Answer 6

natural selection

Question 7

The observable characteristics of an organism.

Answer 7

phenotype

Question 8

Rearrangements of genetic material during sexual reproduction that result in the production of offspring that have combinations of alleles that differ from those in either of their parents.

Answer 8

recombination

Question 9

The process by which one species splits into two or more species.

Answer 9

speciation

Question 10

Selection that favors individuals with an intermediate phenotype.

Answer 10

stabilizing selection

Question 11

An organism’s allocation of its limited energy or other resources to one structure or function at the expense of another.

Answer 11

trade-off

Question 12

An event in which a group of organisms gives rise to many new species that expand into new habitats or new ecological roles in a relatively short time.

Answer 12

adaptive radiation

Question 13

One of two or more forms of a gene that result in the production of different versions of the protein that the gene encodes.

Answer 13

allele

Question 14

A pattern of gradual change in a characteristic of an organism over a geographic region.

Answer 14

cline

Question 15

Selection that favors individuals with one extreme of a heritable phenotypic trait.

Answer 15

directional selection

Question 16

Selection that favors individuals with a phenotype at either extreme over those with an intermediate phenotype.

Answer 16

disruptive selection

Question 17

(1) Change in allele frequencies in a population over time. (2) Descent with modification; the process by which organisms gradually accumulate differences from their ancestors.

Answer 17

evolution

Question 18

A branching diagram that represents the evolutionary history of a group of organisms.

Answer 18

evolutionary tree

Question 19

The transfer of alleles from one population to another via the movement of individuals or gametes.

Answer 19

gene flow