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Baby Bio > Chap 14 Speciation and Extinction > Flashcards

Chap 14 Speciation and Extinction Flashcards

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Biology 101 flashcards
1
Q

What is a species?

A

distinct groups of organisms

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2
Q

Who classified species based on appearance?

A

Linnaeus

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3
Q

What was the naming system Linnaeus used?

A

combined the broader classification genus with the term species

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4
Q

The biological species concept defines species by what?

A

reproduction

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5
Q

Modern biologists use the biological species concept to define species based on what?

A

their ability to interbreed and produce fertile offspring

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6
Q

When do new species form?

A

when some individuals can no longer interbreed with the rest of the group

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7
Q

What helps define species?

A

DNA analysis

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8
Q

What do researchers compare when looking at DNA of a species?

A

the nucleotide sequence of genes that organisms have in common

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9
Q

How much of an organisms DNA must be identical to be considered the same species?

A

97%

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10
Q

What causes species to diverge?

A

reproductive barriers

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11
Q

When a subgroup can no longer interbreed and produce fertile offspring what happens?

A

it is considered a new species

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12
Q

What happens to the subgroups gene pool when it becomes a new species?

A

it shifts and begins to follow its own independent evolutionary path

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13
Q

What type of reproductive barriers prevent fertilization?

A

prezygotic

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14
Q

What type of reproductive barriers prevent development of fertile offspring?

A

postzygotic

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15
Q

What are the types of Prezygotic reproductive barriers?

A 
habitat isolation
temporal isolation
behavioral isolation
mechanical isolation
gametic isolation
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16
Q

What is habitat isolation?

A

different environments (ladybugs feed on different plants)

17
Q

What is temporal isolation?

A

active or fertile at different time (field crickets mature at different rates)

18
Q

What is behavioral isolation?

A

different courtship activities (frog mating calls differ)

19
Q

What is mechanical isolation?

A

mating organs or pollinators are incompatible (sage species use different pollinators)

20
Q

What is gametic isolation?

A

gametes cannot unite (sea urchin gametes are incompatible)

21
Q

What are postzygotic reproductive barriers?

A

hybrid inviability
hybrid infertility
(sterility)
hybrid breakdown

22
Q

What is hybrid inviability?

A

hybrid offspring fail to reach maturity (hybrid eucalyptus seeds and seedlings are not viable)

23
Q

What is hybrid infertility (sterility)?

A

hybrid offspring are unable to reproduce (lion-tiger cross /liger/ is infertile)

24
Q

What is hybrid breakdown?

A

second-generation hybrid offspring have reduced fitness (offspring of hybrid mosquitos have abnormal genitalia)

25
Q

What defines two types of speciation?

A

spatial patterns

26
Q

Reproductive barriers can arise from what?

A

physical or nonphysical separation

27
Q

What are the types of speciation?

A

Allopatric

Sympatric

28
Q

What is Allopatric speciation?

A

when there is no contact between populations (physical barrier)

29
Q

What is sympatric speciation?

A

When there is continuous contact between populations (nonphysical barrier)

30
Q

What can lead to allopatric speciation?

A

islands (Galapagos tortoise)

31
Q

What can lead to sympatric speciation?

A

microenvironments
(in lake large fish feed near shore small fish feed in deeper waters, fish breed where they eat so they don’t mix together and populations started to acquire genetic differences)

32
Q

Why is it difficult to determine the type of speciation?

A

nature is usually a continuum, from complete reproductive isolation to continuous intermingling

we may not be able to detect the barriers

a barrier is not necessarily the same for each species

33
Q

When can speciation occur?

A

after a mass extinction

34
Q

What can lead to mass extinctions?

A

major environmental changes

35
Q

What happens to organisms that survive a mass extinction event?

A

they are able to exploit new resources in the changed environment, so they diversify after the others die

36
Q

When is the sixth mass extinction?

A

now

37
Q

Why are current extinction rates accelerating?

A

human activity

38
Q

How do humans profoundly alter the environment?

A

causing habitat loss and fragmentation

creating pollution

introducing nonnative species

overharvesting

39
Q

What are especially vulnerable areas affected by human activity?

A

islands

Baby Bio (21 decks)

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