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Biology🧪🌱💦 > Lecture 20 > Flashcards

Lecture 20 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is Microevolution?

A

changes in allele frequencies in a
population (with in the same species)

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2
Q

What is Macroevolution?

A

Evolutionary change above the species level

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3
Q

What does this include?

A

Includes the origin of a new group of organisms (speciation) or the cumulative evolutionary change over a long period

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4
Q

What is Speciation?

A

the process by which one species splits into
2 or more species, i.e. new species

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5
Q

What is Evolutionary theory?

A

Must explain how new species originate in addition to how populations evolve

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6
Q

What has traditionally been used to distinguish species?

A

Morphological differences.

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7
Q

What does the biological species concept emphasize?

A

emphasizes reproductive isolation

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8
Q

How is a population or group of populations defined according to the biological species concept?

A

As a group whose members can potentially breed with each other to produce viable, fertile offspring.

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9
Q

What distinguishes this group from others according to the biological species concept?

A

They CANNOT produce viable, fertile offspring with members of other species.

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10
Q

What are isolating mechanisms?

A

they are biological factors that impede members of two species from producing viable, fertile hybrids.

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11
Q

What do isolating mechanisms do?

A

They preserve genetic integrity

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12
Q

How do they preserve genetic integrity? By preventing WHAT?

A

by preventing gene flow between species

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13
Q

What do prezygotic barriers impede or hinder?

A

impede mating between species or HINDER fertilization if members of different species attempt to mate

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14
Q

What do prezygotic barriers ensure?

A

They ensure that a zygote is never produced

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15
Q

How many types of prezygotic barriers are there?

A

5

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16
Q

What do postzygotic barriers prevent?

A

often prevent the hybrid zygote from developing into a viable, fertile adult

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17
Q

complete the sentence: This means that while a zygote is produced…..

A

the resulting hybrid cannot reproduce itself once mature

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18
Q

How many types of postzygotic barriers exist?

A

3 types

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19
Q

For Prezygotic Barriers, name an example of habitat isolation

A

Aquatic vs Terrestrial

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20
Q

For Prezygotic Barriers, name an example of temporal isolation

A

Breed at different times of the year

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21
Q

Name an example of behavioral isolation

A

For Prezygotic Barriers, the female will only mate with a male with a certain courtship ritual

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22
Q

For Prezygotic Barriers, name an example of mechanical isolation (2)

A

-Shells spiral in different directions
-Genital openings not aligned

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23
Q

For Prezygotic Barriers, name an example of gametic isolation

A

Sperm will not fertilize the egg of another species (i.e. unable to survive, cannot penetrate egg…)

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24
Q

What are the 3 types of Postzygotic Barriers?

A
  • Reduced Hybrid Viability
  • Reduced Hybrid Fertility
  • Hybrid Breakdown
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25
Q

When you think of Prezygotic Barriers, what should you immediately think of?

A

Prezygotic Barriers -> impede fertilization

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26
Q

When you think of Postzygotic Barriers, what should you immediately think of?

A

Postzygotic Barriers -> impede hybrid offspring

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27
Q

The biological species concept cannot be applied to 2 types of organisms, which ones?

A
  • Asexual organisms
  • Organisms about which little is known regarding their reproduction (ex. Fossils)
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28
Q

What are 2 other definitions of Species?

A

1) The morphological species concept
2) The ecological species concept
3) The phylogenetic species concept

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29
Q

What is the main idea of The morphological species concept?

A

Characterizes a species in terms of its body shape, size, and other structural features

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30
Q

What is the main idea of The ecological species concept?

A

Views a species in terms of its ecological NICHE

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31
Q

What is the main idea of The phylogenetic species concept?

A

trace the phylogenetic history of organisms (comparing morphology & molecular sequences)

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32
Q

Speciation can occur in two ways, name them:

A

1) Allopatric speciation
2) Sympatric speciation

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33
Q

Which one is related to the geographic separation of populations?

A

Allopatric speciation

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34
Q

What does the geographic separation of populations restrict?

A

gene flow

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35
Q

When does Sympatric speciation occur?

A

occurs in geographically overlapping
populations

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36
Q

Sympatric speciation is when biological factors reduce gene flow, give 2 examples of these biological factors

A
  • chromosomal changes
  • non-random mating
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37
Q

Let’s talk about Allopatric speciation: What are examples of geographic barriers that cause separation?

A

Mountain ranges, glaciers, land bridges, lakes splitting, and island colonization.

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38
Q

The significance of the barrier depends on what?

A

on the ability of organisms to move about

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39
Q

How do gene pools diverge (move about) in allopatric speciation?

A

Due to different selective pressures, mutations, and genetic drift (bottleneck and founder effects).

40
Q

Define allopatric speciation.

A

It’s when separated populations evolve differences preventing interbreeding and fertile offspring production.

41
Q

What is sympatric speciation?

A

when speciation occurs in populations that OVERLAP geographically.

42
Q

This overlap means that populations of species occupy the same WHAT?

A

the same RANGE

43
Q

What are the 2 ways Sympatric Speciation can occur?

A
  • A change in *ploidy (plants)
    – A change in ecology (animals)
44
Q

How does change occur in ecology for animals (2)?

A

habitat & sexual selection

45
Q

What is polyploidy?

A

the presence of extra sets of chromosomes
(more than diploid number)

46
Q

How does polyploidy happen in cells?

A

due to accidents during cell division

47
Q

How has polyploidy influenced evolution?

A

It has caused the evolution of some plant species.

48
Q

In Sympatric Speciation, what is an AUTOpolyploid?

A

an individual that has more than two chromosome sets, all derived from a single (SAME) species

49
Q

What happens during cells division to get an autopolyploid?

A

failure of cell division = tetraploid branch
gametes produced are diploid
offspring = viable & fertile (a new biological species)

50
Q

What is an ALLOpolyploid?

A

a species with multiple sets of chromosomes derived from DIFFERENT species

51
Q

How can a sterile hybrid become fertile in subsequent generations?

A

Various mechanisms may transform a sterile hybrid into a fertile polyploid over time.

52
Q

Are polyploid hybrids fertile with each other?

A

Yes (can produce fertile offspring among themselves)

53
Q

Can polyploid hybrids breed with either parent species?

A

no

54
Q

What is an example of a change in ecology affecting speciation?

A

The North American maggot fly (Rhagoletis pomonella)

55
Q

What was the original habitat of the North American maggot fly?

A

Native hawthorn trees

56
Q

What happened about 200 years ago regarding the habitat of some maggot fly populations?

A

Some populations colonized newly introduced apple trees

57
Q

How has the change in habitat affected the maggot fly populations?

A

Flies feeding on apples have been selected for more rapid development due to the faster maturation of apples compared to hawthorn fruit.

58
Q

What is the consequence of this difference in development rates?

A

B/c apples mature more quickly than hawthorn fruit, they don’t develop or mature at the same rate or time
(apple-feeding flies more rapid development)

59
Q

What does this situation suggest about speciation?

A

Speciation is underway, as indicated by the temporal isolation between the two groups of maggot flies

60
Q

Why has Lake Victoria’s cichlid fish population undergone explosive adaptive radiation? (due to what?)

A

Due to specialization for exploiting different food and other resources.

61
Q

How old is Lake Victoria, and how many species of cichlid fishes does it house?

A

The lake is only 12,000 years old but is home to 600 species of cichlid fishes.

62
Q

What role does sexual selection play in the diversification of cichlid fishes?

A

Sexual selection = where females choose mates based on APPEARANCE

63
Q

Sexual selection contributes to what?

A

it contributes to speciation

64
Q

How do females select mates among cichlid fishes? (under normal and orange light)

A

Females have specific COLOR preferences. Under normal light, they choose males of their own species, but under orange light conditions, they may mate with other species.

65
Q

What reproductive barrier keeps the gene pools of different cichlid species separate?

A

Mate choice, primarily based on color preferences, acts as the main reproductive barrier.

66
Q

What are the 2 different models that have been developed to explain the evolution as observed in the fossil record models?

A

1) Gradualism
2) Puntuated equilibrium

67
Q

Which one has a continuous evolution over long periods? and which one has an evolution over short periods?

A

1) Gradualism -> LONG PERIODS
2) Punctuated equilibrium -> SHORT PERIODS

68
Q

Punctuated equilibrium is triggered by what?

A

by environmental changes

69
Q

Why is gradualism over a long period?

A

Since the fossil record is incomplete, we rarely see all stages of evolution.

70
Q

How long does speciation occur according to the theory of punctuated equilibrium?

A

speciation occurs in a relatively short period (Short = 1000s of years!)

71
Q

What is macroevolution?

A

refers to evolutionary changes above the species level, where phenotypic differences are so significant that new species are assigned to different taxonomic categories.

72
Q

Evolutionary Novelties can arise from 2 ways, name them:

A

1) Gradual refinement
2) Major body changes

73
Q

Gradual refinement of what?

A

of existing structures (cumulative change over millions of speciation episodes)

74
Q

How does the gradual refinement of existing structures contribute to evolution?

A

natural selection improves structures based on their current utility rather than anticipation of future needs.

75
Q

What does the fossil record indicate about the evolution of flight?

A

Light bones predated flight
(suggesting they initially served a different function on the ground, possibly in agile, bipedal dinosaurs)

76
Q

What was the original function of feathers? (3)

A

used for courtship, thermoregulation, or camouflage

77
Q

How did natural selection adapt structures for flight?

A

Once FLIGHT BECAME ADVANTAGEOUS, natural selection gradually changed structures to be adapted for flight, enhancing their aerodynamic properties.

78
Q

Major changes in body can result from changes in WHAT (2)? (genes that control what and what)

A

a) genes that control development
b) genes that control the spatial organization of body parts

79
Q

For mutation in genes that control development, a change in what (2) has led to many striking evolutionary transformations?

A

change in the rate or timing of developmental events

80
Q

Why are the feet of the tree-dwellers relevant to this subject?

A

The feet of the tree-dwellers are adapted or climbing vertically, with shorter digits and more webbing.

81
Q

What would be the result if mutations in
regulatory genes switched off foot growth early?

A

Stunted feet

82
Q

For mutation in genes that control spacial organization, what role do Hox genes play in animal embryo development?

A

Hox genes provide POSITIONAL INFORMATION in an animal embryo

83
Q

The positional information guides cells to develop into what?

A

to develop into structures appropriate for specific locations

84
Q

What is one major transition in the evolution of vertebrates?

A

the development of walking legs in tetrapods from the fins of fishes.

85
Q

How do mutations in genes controlling spatial organization contribute to evolutionary change?

A

Mutations in spatial organization genes, such as Hox genes, lead to significant evolutionary changes by altering/reshaping the developmental pathways and resulting structures in an organism’s body plan.

86
Q

Why is extinction important in evolution?

A

Extinction creates opportunities for adaptive evolution by opening up empty ecological niches.

87
Q

How does extinction facilitate evolution?

A

Extinction creates vacant ecological niches, allowing new species to evolve and fill those spaces.

88
Q

What are some geological periods?
Name the three major eras:

A

Paleozoic, Mesozoic, Cenozoic.

89
Q

List some periods within these eras:

A

Permian, Triassic, Jurassic, Cretaceous, Tertiary/Quaternary

90
Q

How did the extinction of dinosaurs affect mammals?

A

Mammals were able to diversify due to the disappearance of dinosaurs.

91
Q

Explain the advantages this extinction provided for mammal evolution.

A

*more food, less competition/risk of predation

92
Q

What are regional adaptive radiations?

A

Periods of evolutionary change where groups of organisms form many new species to occupy various ecological roles in a specific area.

93
Q

Why are regional adaptive radiations significant/important?

A

They lead to the diversification of species into different ecological niches, exploiting new resources and habitats.

94
Q

How do regional adaptive radiations occur?

A

They occur when new ecological opportunities arise

95
Q

Often due to what are there new ecological opportunities?

A

often due to geographical isolation, environmental changes, or the extinction of competing species.

96
Q

Give an example of regional adaptive radiation.

A

Bird species diversification on islands, where new ecological niches are available due to the absence of certain mainland bird species.

Biology🧪🌱💦 (21 decks)

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