Chapter 24

Question 1

Allopatric speciation

Answer 1

Gene flow is interrupted or reduced when a population is divided into geographical subpopulations

Question 2

Sympatric speciation

Answer 2

Speciation takes place in geographically overlapping population. Gene flow is reduced by factors other than geographic speciation

Question 3

How does allopatric speciation occur?

Answer 3

subpopulations evolve independently through mutation, natural selection, and genetic drift

Question 4

Types of Allopatric speciation

Answer 4

1. Definition of barriers depends on the organism
2. When individuals colonize new areas
3. Reproductive isolation

Question 5

How can reproductive isolation arise?

Answer 5

a by-product of genetic divergence

Question 6

Microevolution

Answer 6

consists of changes in allele frequency in a population over time

Question 7

Macroevolution

Answer 7

broad patterns of evolutionary changes above the species level

Question 8

Speciation

Answer 8

process in which one species splits into two or more species

Question 9

Speciation is the focal point of evolutionary theory and…

Answer 9

forms a conceptual bridge between micro and macro evolution

Question 10

Species

Answer 10

Latin for “kind” or “appearance”

Question 11

Hybrids

Answer 11

the offspring of crosses between members of different species

Question 12

Biological species concept defines species as…

Answer 12

a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring

Question 13

Aspects of biological species concept

Answer 13

1. Gene flow between populations holds a species together genetically
2. Reproductive isolation

Question 14

Reproductive isolaltion

Answer 14

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

Question 15

Types of reproductive isolation

Answer 15

1. Prezygotic barriers

2. Postzygotic barriers

Question 16

Prezygotic barriers

Answer 16

“before the zygote” -block fertilization

Question 17

Types of prezygotic barriers

Answer 17

1. Habitat isolation
2. Temporal isolation
3. Behavioral isolation

Question 18

Habitat isolation

Answer 18

breed in different places in the same range

- not isolated by obvious barrier; rarely encounter each other

Question 19

Temporal isolation

Answer 19

breed during different times of the day, different seasons, or years

Question 20

Behavioral isolation

Answer 20

courtship rituals and other behaviors enable mate recognition and prevent breeding

Question 21

After Mating Attempt, Prior to Fertilization

Answer 21

1. Mechanical isolation

2. Gametic isolation

Question 22

Mechanical isolation

Answer 22

mating attempted, but morphological differences prevent completion

Question 23

Gametic isolation

Answer 23

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

Question 24

Postzygotic barriers

Answer 24

“after the zygote” -contributes to reproductive isolation after formation of hybrid zygote

Question 25

Types of postzygotic barriers

Answer 25

1. Reduced hybrid viability
2. Reduced hybrid fertility
3. Hybrid breakdown

Question 26

Reduced hybrid viability

Answer 26

genes of different parent species interact in ways that impair development and survival

Question 27

Reduced hybrid fertility

Answer 27

hybrid survives, but is steril

Question 28

Hybrid breakdown

Answer 28

first generationviable and fertile, but when mate with each other or either parent species, offspring are feeble or sterile

Question 29

Limitations to Biological Species Concept

Answer 29

1. cannot be bapplied to fossils
2. cannot be applied to asexual organisms
3. emphasizes absence of gene flow, but gene flow can occur between distinct species

Question 30

Morphological species concept

Answer 30

defines species by strucural features

Question 31

What does the morphological species apply to

Answer 31

1. sexual and asexual species

2. fossils

Question 32

What does morphological species concept rely on?

Answer 32

subjective criteria (debatable)

Question 33

Examples of subjective criteria

Answer 33

Monarch and Viceroy

Question 34

Ecological species concept

Answer 34

defines species in terms of its ecological niche

Question 35

Niche

Answer 35

species “role” in environment defined as the set of conditions in which a viable populaiton can be maintained

Question 36

What does niche apply to?

Answer 36

sexual and asexual species

Question 37

What does niche emphasize?

Answer 37

the role of disruptive selection