Chapter 24

Question 1

an evolutionary process in which one species splits into two or more species.

Answer 1

speciation

Question 2

evolutionary change elbow the species level; change in the allele frequencies in a population over generations.

Answer 2

microevolution

Question 3

evolutionary change above the species level, including the origin of a new group of organisms or a shift in the broad pattern of evolutionary change over a long period of time. Examples include the appearance of major new features of organisms and the impact of mass extinctions on the diversity of life and its subsequent recovery.

Answer 3

macroevolution

Question 4

definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.

Answer 4

biological species concept

Question 5

a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not form viable, fertile offspring with members of other such groups.

Answer 5

species

Question 6

the existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.

Answer 6

reproductive isolation

Question 7

offspring that results from the mating of two individuals from two different species or two true-brewing varieties of the same species.

Answer 7

hybrid

Question 8

a reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted.

Answer 8

prezygotic barriers

Question 9

a reproductive barrier that prevent hybrid zygotes produced by two different species from developing into viable, fertile adults.

Answer 9

postzygotic barriers

Question 10

a definition of species in terms of measurable anatomical criteria.

Answer 10

morphological species concept

Question 11

a definition of species in terms of ecological niche, the sum of how members of the living species interact with the nonliving and living parts of their environment.

Answer 11

ecological species concept

Question 12

a definition of species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life.

Answer 12

phylogenetic species concept

Question 13

the formation of new species in populations that are geographically isolated from one another.

Answer 13

allopatric speciation

Question 14

a chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.

Answer 14

polyploidy

Question 15

an individual that has more than two chromosome sets that are all derived from a single species.

Answer 15

autopolyploid

Question 16

a fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes.

Answer 16

allopolyploid

Question 17

a geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry.

Answer 17

hybrid zone

Question 18

a process in which natural selection strengthens prezygotic barriers to reproduction, thus reducing the chances of hybrid formation. Such a process is likely to occur only fi hybrid offspring are less fit than members of the parent species.

Answer 18

reinforcement

Question 19

in the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change.

Answer 19

punctuated equilibria