Chapter 24

Question 1

How do prezygotic barriers block fertilization from occurring?

Answer 1

• stop different species from trying to mate
• prevent successful mating
• disrupt fertilization if mating works

Question 2

Consists of changes in allele frequency in a population over time

Answer 2

Microevolution

Question 3

Refers to broad patterns of evolutionary change above the species level

Answer 3

Macroevolution

Question 4

States that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.

Answer 4

Biological species concept

Question 5

What does the biological species concept say?

Answer 5

A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring. They do not breed successfully with members of other populations.

Question 6

The existence of biological factors, or barriers, that impede two species from producing viable, fertile offspring

Answer 6

Reproductive isolation

Question 7

The offspring of crosses between different species

Answer 7

Hybrids

Question 8

When two species do not encounter each other at all (or very rarely) because they live in different habitats. They are not isolated by physical barriers,but they still do not encounter each other often because they live in different habitats

Answer 8

Habitat isolation

Question 9

When species that breed at different times, seasons, or years cannot mix their gametes.

Answer 9

Temporal isolation

Question 10

When behaviors that are unique to a species, such as courtship rituals, are effective barriers to mating.

Answer 10

Behavioral isolation

Question 11

When morphological differences can prevent successful completion of mating

Answer 11

Mechanical isolation

Question 12

When the sperm of one species may not be able to fertilize eggs of another species

Answer 12

Gametic isolation

Question 13

List 3 post-zygotic barriers

Answer 13

1) reduced hybrid viability
2) reduced hybrid fertility
3) hybrid breakdown

Question 14

What are the 5 types of isolation?

Answer 14

1) Habitat
2) Temporal
3) Behavioral
4) Mechanical
5) Gametic

Question 15

What are the two types of speciation?

Answer 15

Allopatric and sympatric

Question 16

Gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations. Give an example.

Answer 16

Allopatric speciation; Example: the flightless cormorant (bird) from the Galapagos probably originated from a flying species on the mainland.

Question 17

What are the 3 factors that can cause sympatric speciation to occur by reducing gene flow?

Answer 17

1) polyploidy
2) sexual selection
3) habitat differentiation

Question 18

Is polyploidy (presence of extra sets of chromosomes) more common in plants or animals?

Answer 18

Plants

Question 19

A species with multiple sets of chromosomes derived from different species

Answer 19

Allopolyploid

Question 20

An individual with more than two chromosome sets, derived from a single species

Answer 20

Autopolyploid

Question 21

A region in which members of different species mate and produce hybrids

Answer 21

Hybrid zone

Question 22

The origin of new species

Answer 22

Speciation

Question 23

Broad patterns of changes in species

Answer 23

Macroevolution

Question 24

Speciation that happens in populations that geographically overlap

Answer 24

Sympatric speciation

Question 25

Extra sets of chromosomes because of accidents during cell division

Answer 25

Polyploidy

Question 26

List the 3 possible outcomes when species meet in a hybrid zone

Answer 26

Reinforcement
Fusion
Stability

Question 27

T or F: Sometimes speciation requires change in one or many genes

Answer 27

True

Question 28

Changes in allele frequency in a population over time

Answer 28

Microevolution

Question 29

How is a hybrid created?

Answer 29

When different species breed

Question 30

What are two forms of reproductive isolation barriers?

Answer 30

Prezygotic and postzygotic

Question 31

What are some examples of prezygotic barriers?

Answer 31

Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, gametic isolation

Question 32

What are some examples of postzygotic barriers?

Answer 32

Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

Question 33

Gene flow is interrupted or reduced when a population is divided into geographically isolated sub-populations

Answer 33

Allopatric speciation

Question 34

Speciation that takes place in geographically overlapping populations

Answer 34

Sympatric speciation

Question 35

Periods of apparent status punctuated by sudden change

Answer 35

Punctuated equilibria

Question 36

T or F: Regions with many geographic barriers typically have more species than regions with fewer barriers

Answer 36

True

Question 37

Give two examples of viable offspring that surpass prezygotic barriers

Answer 37

1) Mule

2) Donkey

Question 38

What do biologists compare when grouping organisms?

Answer 38

Morphology, physiology, and DNA sequence

Question 39

The making of a new species

Answer 39

Speciation

Question 40

What occurs when hybrids survive but are sterile?

Answer 40

Reduced hybrid fertility

Question 41

Where reinforcement occurs, should reproductive barriers be stronger for sympatric or allopatric species?

Answer 41

Sympatric

Question 42

Views a species in terms of its ecological niche

Answer 42

Ecological species concept

Question 43

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

Answer 43

Reproductive isolation