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Biology 221 > Chapter 24 > Flashcards

Chapter 24 Flashcards

The Origin of Species

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1
Q

What is a species?

A

A group of organisms that can reproduce and create fertile offspring.

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2
Q

What is a prezygotic reproductive barrier?

A

A barrier that affects reproduction before zygote formation.

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3
Q

What is a post-zygotic reproductive barrier?

A

A mechanism that blocks reproduction after fertilization and zygote formation.

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4
Q

What is the different between a pre-zygotic and post-zygotic reproductive barrier?

A

Pre is factors that prevent fertilization, and Post is factors that that kill the organism after fertilization.

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5
Q

What are the 5 pre-zygotic barriers?

A

Habitat Isolation
Temporal Isolation
Behavioral Isolation
Mechanical Isolation
Gametic Isolation

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6
Q

What is an example of Habitat Isolation?

A

Some gardner snakes like near bodies of water and some in the fields. They are isolated by location and have different prey, and are unlikely to breed.

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7
Q

What is an example of Temporal Isolation?

A

Certain skunks only mate during certain seasons, so the different skunks can’t physically reproduce due to the time of mating.

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8
Q

What is an example of Behavioral Isolation?

A

When the presence of absence of certain behaviors prevent reproduction from taking place. If fireflies don’t use the male pattern to mate with the female, they wont get a mate.

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9
Q

What is an example of Mechanical Isolation?

A

When shape or function of an organism prevents the reproduction of that. Flowers with the incorrect shape will not receive pollen because it doesn’t have the correct shape for a pollinator.

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10
Q

What is an example of Gametic Isolation?

A

When gametes of a different species fail to attract one another. In sea water there is a lot of sperm and egg, however they can’t fertilize because they’re different species.

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11
Q

What is a potential cause of Hybrid Breakdown?

A

When 2 genetically different corn strands reproduce but once that offspring tries to reproduce they have lower chances.

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12
Q

How does Hybrid Breakdown maintain separate species even if fertilization occurs?

A

The hybrid offspring is not able to reproduce, and therefore is unable to populate a new species.

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13
Q

What is allopatric speciation?

A

Allopatric speciation is the result of speciations due to reproductive isolation.

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14
Q

What is sympatric allocation?

A

Sympatric allocation is divergence in place due to intrinsic factors such as sexual selection, habitat differentiation, and polyploidy.

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15
Q

What are the mechanisms that might lead up to genetic divergence of isolated gene pools?

A

The freeway example, speciation occur in these spiders because in between the 12 lanes there is some land and it is so hard to reach in LA.

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16
Q

How does reproductive isolation evolve?

A

By separation following drift/selection.

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17
Q

What is an example of the evolution of a pre-zygotic barrier?

A

Fruit flies refusing to mate with a male due to their physical traits.

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18
Q

What is an example of the evolution of a post-zygotic barrier?

A

Monkey flower hybrid fertility inversely proportional to distance.

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19
Q

What is sympatric speciation?

A

A new species evolves amidst parent population, no geographic isolation.

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20
Q

How can polyploidy cause reproductive isolation?

A

Polyploidy can interfere with chromosome separation in anaphase 1. Meiosis will not produce viable gametes.

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21
Q

What is an autopolyploid?

A

Multiple chromosome sets from one species.

22
Q

What is an allopolyploid?

A

Hybrids with chromosome sets from different species.

23
Q

What is an example of an autopolyploid?

A

An individual with more than 2 chromosome sets, derived from a single species. The white stuergon plant.

24
Q

What is an example of an allopolyploid?

A

A species with multiple sets of chromosomes derived from different species. Wheat and Rye Cross.

25
Q

How has habitat differentiation led to sympatric speciation in North American maggot flies?

A

Apple maggot flies started out preferring hawthorn trees but through sympatric speciation, the now prefer apple trees.

26
Q

How has sexual selection has led to sympatric adaptive radiation in the cichlids of Lake
Victoria?

A

Evidence suggests that mate choice based on male breeding coloration is the main reproductive barrier keeping 2 gene pools separate.

27
Q

How can the processes of speciation potentially be reversing due to pollution in Lake Victoria?

A

Researchers believe that many other species have disappeared due to pollution that has made the water so murky they cichlids can’t see the color.

28
Q

What is the “hybrid zone”?

A

A region in which members of different species meet and mate producing at least some offspring with mixed ancestry. This can occur when allopatric populations come back into contact with one another.

29
Q

What are the 3 potential outcomes for the “hybrid zone”?

A

Reinforcement
Fusion
Stability

30
Q

What is the punctuated equilibrium theory and what evidence supports it?

A

The idea that evolution occurs in spurts rather than slow and steady. Fossil record affirms this.

31
Q

What are the various points that are considered when hypothesizing about how many gene altercations are necessary for a new species to emerge?

A

There are so many potential outcomes. There really isn’t one answer due to variability.

32
Q

What is speciation?

A

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

33
Q

What is microevolution?

A

The changes in an allele frequency over time.

34
Q

What is macro evolution?

A

The broad patterns of evolutionary change above the species level.

35
Q

What is the biological species concept?

A

That a species is a group of populations capable of interbreeding and creating viable fertile offspring. Can not breed successfully with members of other populations.

36
Q

What is reproductive isolation?

A

The existence of 2 biological factors that impede 2 species from producing viable and fertile offspring.

37
Q

What are hybrids?

A

The offspring of crosses between different species.

38
Q

How is reproductive isolation classified?

A

Either before or after fertilization. Pre-zygotic or Post-zygotic.

39
Q

What are the 3 post-zygotic barriers?

A

Reduced Hybrid Viability
Reduced Hybrid Offspring
Hybrid Breakdown

40
Q

What are the 3 post-zygotic barriers?

A

Reduced Hybrid Viability
Reduced Hybrid Fertility
Hybrid Breakdown

41
Q

What is an example of Reduced Hybrid Viability?

A

In amphibians, they can interbreed with closely related species, however offspring has smaller chances of survival.

42
Q

What is an example of Reduced Hybrid Fertility?

A

When donkey and horse are mated and they get a mule. They are sterile, however the initial offspring survived.

43
Q

What is an example of Hybrid Breakdown?

A

When the parent plant crosses with another species, and creates offspring, however that offspring can not reproduce at the same percentage, so as generations progress, chances go down.

44
Q

What is the morphological species concept?

A

When the structures of an organism is defining.

45
Q

What is the ecological species concept?

A

When a species is viewed in terms of ecological niche.

46
Q

What is the phylogenetic species concept?

A

When a species is defined as the smallest group of individuals on the phylogenetic tree.

47
Q

What is an example of Reinforcement in Hybrid Zones?

A

The strengthening of reproductive barriers, so hybrids eventually cease to be formed.

48
Q

What is an example of fusion in Hybrid Zones?

A

Weakening of reproductive barriers, the 2 species fuse.

49
Q

What is an example of Stability in Hybrid Zones?

A

Continued production of hybrid individuals.

50
Q

What is punctuated equilibrium theory?

A

The theory that evolutionary change occurs in spurts instead of slow and steady.

Biology 221 (10 decks)

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