Chapter 24 The Origins Of Species Flashcards

1
Q

The origin of new species, is at the focal point of evolutionary theory

A

Speciation

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2
Q

Consist of changes in allele frequency in a population over time

A

Microevolution

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3
Q

Refers to broad patterns of evolutionary change above the species level

A

Macroevolution

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4
Q

Group of populations whose members have the potential to interbreed in nature

Produce viable, fertile offspring

Do not breed successfully with other populations

A

Species

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5
Q

____________ between populations holds the phenotype of a population together

A

Gene flow

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6
Q
  • The existence of biological factors (barriers) that impede two species from producing viable, fertile offspring
  • can be classified by whether factors occur before or after fertilization
A

Reproductive isolation

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7
Q

What does reproductive limitation limit the formation of?

A

Hybrids

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8
Q

What are the reproductive barriers?

A
  • habitat isolation
  • temporal isolation
  • behavioral isolation
  • mechanical isolation
  • gametic isolation
  • reduce hybrid viability
  • reduced hybrid fertility
  • hybrid breakdown
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9
Q

Block fertilization from occurring by

  • impeding different species from attempting to mate
  • preventing the successful completion of mating
  • hindering fertilization if mating is successful
A

Prezygotic barriers

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10
Q

Species that breed at different times of the day, different seasons or different years cannot mix their gametes

A

Temporel isolation

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11
Q

Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers

A

Habitat isolation

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12
Q

Courtship rituals and other behaviors unique to a species are effective barriers

A

Behavioral isolation

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13
Q

Morphological differences can prevent successful mating

A

Mechanical isolation

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14
Q

Sperm of one species may not be able to fertilize eggs of another species

A

Gametic isolation

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15
Q

Prevents the hybrid from developing into a viable, fertile adult:

  • reduce hybrid viability
  • reduced hybrid fertility
  • hybrid breakdown
A

Postzygotic barriers

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16
Q

Genes of the different parent species may interact and impair the hybrids development

A

Reduced hybrid viability

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17
Q

Even if hybrids are Vigorous, they may be sterile

A

Reduced hybrid fertility

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18
Q

Some first generation hybrids are fertile, but when they mate with another species or with either parent species offspring of the next generation are feeble or sterile

A

Hybrid breakdown

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19
Q

Cannot be applied to fossils or asexual organisms (prokaryotes)

Emphasizes absence of Gene flow

Ex: growler bear?

A

Biological species concept

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20
Q

Can Gene flow occur between distinct species?

A

Yes

21
Q

Applies to sexual and asexual species but relies on subjective criteria

Appearances

A

Morphological species concept

22
Q

Applies to sexual and asexual species and emphasizes the role of disruptive selection. Where they live, food sources.

A

Ecological species concept

23
Q

Defined as a species as the smallest Group of individuals on a phylogenetic tree

It applies to sexual and asexual species, but it can be difficult to determine the degree of difference required for separate species

A

Phylogenetic species concept

24
Q

Can speciation take place with or without geographic separation?

A

Yes

25
Q

Speciation can occur in what two ways ?

A
  • allopatric speciation

- sympatric speciation

26
Q

How do the numbers of geographic barriers affect the numbers of species in the area?

A

More variety of species

27
Q

What can result as the distance between populations increase?

A

Reproductive isolation

28
Q

Speciation takes place in graphically overlapping populations

More common In plants

A

Sympatric speciation

29
Q

What are the three ways sympatric speciation can occur?

A
  • polyploidy
  • habitat differentiation
  • sexual selection
30
Q

The presence of extra sets of chromosomes due to accidents during cell division

Much more common in plants than in animals

A

Polyploidy

31
Q

An individual with more than two chromosomes sets derived from one species

A

Autopolyploid

32
Q

A species with multiple sets of chromosomes derived from different species

Sterile hybrid

A

Allopolyploid

33
Q
  • An individual with more than two chromosome sets

- derive from one species

A

Autoployploid

34
Q

Can drive sympatric speciation

Sexual selection for mates

Ex: speciation in Cichlid fish in lake Victoria

A

Sexual selection

35
Q

A reproductive barrier isolates a subset of a population without geographic separation from the Parent species

Can result from polyploidy, natural selection, or sexual selection

A

Sympatric speciation

36
Q

Geographic isolation restricts gene flow between populations

reproductive isolation may then arise by natural selection, genetic drift, or sexual selection in the isolated populations
-even if contact is restored between populations, interbreeding is prevented

A

Allopatric speciation

37
Q

the area where two species meet and mate to form hybrids

A

Hybrid zone

38
Q

The result of mating between species with incomplete reproductive barriers

A

Hybrids

39
Q

What is the level of fitness in hybrids compared with the parent species?

A

Lower

40
Q

What are the three possible outcomes when closely related species meet in a hybrid zone?

A
  • reinforcement
  • Fusion
  • stability
41
Q

Occurs when hybrids are less fit than the parent species. This reinforces natural selection and barriers between them.

A

Reinforcement:

Strengthening reproductive barriers**

42
Q

Does reinforcement strengthen or weaken reproductive barriers?

A

Strengthen

43
Q

Are reproductive barriers stronger in allopatric or sympatric species?

A

Sympatric

Ex: birds that look the same in allopatric speciation

Birds that look completely different in sympatric speciation, no attempts to mate

44
Q

Fusion (strengthens or weakens) reproductive barriers?

A

Weakens

45
Q

In hybrids zones, Reproductive barriers weaken until the two species become one.

Ex: cichlids

A

Fusion

46
Q

Hybrid survive or reproduce better than the parent species

Continues formation of hybrid individuals

A

Stability

*Not common

47
Q
  • each new species evolves continuously over long spans of time
  • large phenotypic differences that produce new species are due to the accumulation of many small genetic changes
A

Gradualism

48
Q

Species in equilibrium (stasis) for long periods and then short rapid burst of change

A

Punctuated Equilibrium

49
Q

The _____________ in the fossil record and evidence from lab studies suggest that speciation can be rapid

A

Punctuated pattern