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Flashcards in Chapter 24 Deck (43):
1

How do prezygotic barriers block fertilization from occurring?

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

2

Consists of changes in allele frequency in a population over time

Microevolution

3

Refers to broad patterns of evolutionary change above the species level

Macroevolution

4

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

Biological species concept

5

What does the biological species concept say?

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.

6

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

Reproductive isolation

7

The offspring of crosses between different species

Hybrids

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

Habitat isolation

9

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

Temporal isolation

10

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

Behavioral isolation

11

When morphological differences can prevent successful completion of mating

Mechanical isolation

12

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

Gametic isolation

13

List 3 post-zygotic barriers

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

14

What are the 5 types of isolation?

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

15

What are the two types of speciation?

Allopatric and sympatric

16

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

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

17

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

1) polyploidy
2) sexual selection
3) habitat differentiation

18

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

Plants

19

A species with multiple sets of chromosomes derived from different species

Allopolyploid

20

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

Autopolyploid

21

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

Hybrid zone

22

The origin of new species

Speciation

23

Broad patterns of changes in species

Macroevolution

24

Speciation that happens in populations that geographically overlap

Sympatric speciation

25

Extra sets of chromosomes because of accidents during cell division

Polyploidy

26

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

Reinforcement
Fusion
Stability

27

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

True

28

Changes in allele frequency in a population over time

Microevolution

29

How is a hybrid created?

When different species breed

30

What are two forms of reproductive isolation barriers?

Prezygotic and postzygotic

31

What are some examples of prezygotic barriers?

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

32

What are some examples of postzygotic barriers?

Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

33

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

Allopatric speciation

34

Speciation that takes place in geographically overlapping populations

Sympatric speciation

35

Periods of apparent status punctuated by sudden change

Punctuated equilibria

36

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

True

37

Give two examples of viable offspring that surpass prezygotic barriers

1) Mule
2) Donkey

38

What do biologists compare when grouping organisms?

Morphology, physiology, and DNA sequence

39

The making of a new species

Speciation

40

What occurs when hybrids survive but are sterile?

Reduced hybrid fertility

41

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

Sympatric

42

Views a species in terms of its ecological niche

Ecological species concept

43

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

Reproductive isolation