Chapter 26 (Speciation)

Question 1

allopatric speciation

Answer 1

The divergence of populations into different species by physical isolation of populations in different geographic areas.

Question 2

allopatry

Answer 2

Condition in which two or more populations live in different geographic areas.

Question 3

allopolyploid

Answer 3

The state of having more than two full sets of chromosomes (polyploidy) due to hybridization between different species.

Question 4

autopolyploid

Answer 4

The state of having more than two full sets of chromosomes (polyploidy) due to a mutation that doubled the chromosome number.

Question 5

biogeography

Answer 5

The study of how species and populations are distributed geographically.

Question 6

biological species concept

Answer 6

The definition of a species as a population or group of populations that are reproductively isolated from other groups. Members of a species have the potential to interbreed in nature to produce viable, fertile offspring but cannot produce viable, fertile hybrid offspring with members of other species.

Question 7

cryptic species

Answer 7

A species that cannot be distinguished from other species by easily identifiable morphological traits.

Question 8

hybrid zone

Answer 8

A geographic area where interbreeding occurs between two species, sometimes producing fertile hybrid offspring.

Question 9

monophyletic group

Answer 9

An evolutionary unit that includes an ancestral population and all of its descendants but no others. Also called a clade or lineage.

Question 10

morphospecies concept

Answer 10

The definition of a species as a population or group of populations that have measurably different anatomical features from other groups. Also called morphospecies concept.

Question 11

phylogenetic species concept

Answer 11

The definition of a species as the smallest monophyletic group in a phylogenetic tree.

Question 12

polyploidy

Answer 12

The state of having more than two full sets of chromosomes.

Question 13

postzygotic isolation

Answer 13

Reproductive isolation resulting from mechanisms that operate after mating of individuals of two different species occurs. The most common mechanisms are the death of hybrid embryos or reduced fitness of hybrids.

Question 14

prezygotic isolation

Answer 14

Reproductive isolation resulting from mechanisms that operate after mating of individuals of two different species occurs. The most common mechanisms are the death of hybrid embryos or reduced fitness of hybrids.

Question 15

reinforcement

Answer 15

In evolutionary biology, the natural selection for traits that prevent interbreeding between recently diverged species.

Question 16

sister species

Answer 16

Closely related species, which occupy adjacent branches in a phylogenetic tree.

Question 17

species

Answer 17

A distinct, identifiable group of populations that is thought to be evolutionarily independent of other populations and whose members can interbreed. Generally distinct from other species in appearance, behavior, habitat, ecology, genetic characteristics, etc.

Question 18

subspecies

Answer 18

A population that has distinctive traits and some genetic differences relative to other populations of the same species but that is not distinct enough to be classified as a separate species.

Question 19

sympatric speciation

Answer 19

The divergence of populations living within the same geographic area into different species as the result of their genetic (not physical) isolation

Question 20

sympatry

Answer 20

Condition in which two or more populations live in the same geographic area, or close enough to permit interbreeding.

Question 21

vicariance

Answer 21

The physical splitting of a population into smaller, isolated populations by a geographic barrier.