Chapter 23

Question 1

Allopatric Speciation

Answer 1

The formation of two species from one when reproductive isolation occurs because of the interposition of (or crossing of) a physical geographic barrier such as a river. Also called geographic speciation. (Contrast with sympatric speciation.)

Question 2

Allopolyploidy

Answer 2

The possession of more than two chromosome sets that are derived from more than one species.

Question 3

Autopolyploidy

Answer 3

The possession of more than two entire chromosomes sets that are derived from a single species.

Question 4

Biological Species Concept

Answer 4

The definition of a species as a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. (Contrast with lineage species concept; morphological species concept.)

Question 5

Evolutionary Radiation

Answer 5

The proliferation of many species within a single evolutionary lineage.

Question 6

Hybrid zone

Answer 6

A narrow zone where two populations interbreed, producing hybrid individuals.

Question 7

Hybridize

Answer 7

(1) In genetics, to combine the genetic material of two distinct species or of two distinguishable populations within a species. (2) In molecular biology, to form a double-stranded nucleic acid in which the two strands originate from different sources.

Question 8

Lineage Species Concept

Answer 8

The definition of a species as a branch on the tree of life, which has a history that starts at a speciation event and ends either at extinction or at another speciation event. (Contrast with biological species concept; morphological species concept.)

Question 9

Morphological Species Concept

Answer 9

The definition of a species as a group of individuals that look alike. (Contrast with biological species concept; lineage species concept.)

Question 10

Polyploidy

Answer 10

The possession of more than two entire sets of chromosomes.

Question 11

Postzygotic Reproductive Barriers

Answer 11

Barriers to the reproductive process that occur after the union of the nuclei of two gametes. (Contrast with prezygotic reproductive barriers.)

Question 12

Prezygotic Reproductive Barriers

Answer 12

Barriers to the reproductive process that occur before the union of the nuclei of two gametes (Contrast with postzygotic reproductive barriers.)

Question 13

Reinforcement

Answer 13

The evolution of enhanced reproductive isolation between populations due to natural selection for greater isolation.

Question 14

Reproductive Isolation

Answer 14

Condition in which two divergent populations are no longer exchanging genes. Can lead to speciation.

Question 15

Speciation

Answer 15

The process of splitting one population into two populations that are reproductively isolated from one another.