Biology 100 Unit 14 Flashcards

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1
Q

is the study of major biological changes seen in the fossil record (i.e., obvious structural differences).

A

macroevolution

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2
Q

When changes accumulate to produce a completely distinct group of organisms, we call this ___________.

A

speciation

-This includes the origin of a new species (speciation).

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3
Q

According to the ______________________, a species is a group of members in a population with the potential to interbreed and produce fertile offspring.

A

Biological Species concept

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4
Q

According to the biological species concept a species is a

A

group of members in a population with the potential to interbreed and produce fertile offspring.

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5
Q

Members of different species don’t mate due to

A

reproductive isolation.

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6
Q

The biological species concept can be problematic. – Some pairs of clearly distinct species occasionally
interbreed and produce _____________.

A

hybrids

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7
Q

– For example, grizzly bears and polar bears may interbreed and produce hybrids called ____________.

A

groolarbears

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8
Q

_________________may bring these two bear species together more frequently and produce more hybrids in the wild.

– These 2 distinct species would not be reproductively isolated from each other, therefore difficult to classify as _______________________
– Alternate species concepts can be useful.

A

Melting sea ice

distinct species.

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9
Q

Another species definition is the __________________ ____________, which identifies species in terms of their ecological niche, looking at their role in an community.

A

ecological species definition

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10
Q

The ecological species concept

A

focuses on unique adaptations to particular roles in a

biological community.

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11
Q

or example, two species may be similar in appearance but distinguishable based on

A
  • what they eat

- where they live

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12
Q

Lastly, the ___________________defines a species as the smallest group of individuals that share a common ancestor, forming a branch on an evolutionary tree.

A

phylogenetic species concept

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13
Q

Biologists trace the phylogenetic history of a species by comparing its

A

DNA sequences

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14
Q

Alternate ways of defining species using physical traits, shape, size or other features.

A

Morphological species concept

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15
Q

Give two examples of the morphological species concept

A
  • asexual organisms

- fossils

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16
Q

prevent interbreeding and establish different species.

A

reproductive barriers

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17
Q

What do reproductive barriers do

A

the isolate gene pool

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18
Q

barriers prevent mating between different species.

A

prezgotic or postzygotic

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19
Q

Generally fertile offspring are the result

A

of the same species mating, with few exceptions.

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20
Q

Courtship ritual in blue-footed boobies is an example of one kind of prezygotic barrier, ________________.

A

behavioral isolation

21
Q

Structural differences don’t allow the genitals of these snails to mate

A

mechanical isolation

22
Q

mating or fertilizing occurs at different seasons

A

temporary isolation

23
Q

populations live in different habitats and therefore do not interact

A

habitat isolation

24
Q

Female and Male gametes fail to unite in fertilization

A

gametic isolation

25
Q

Should prezygotic barriers fail and interspecific fertilization occur forming a hybrid zygote, postzygotic barriers are additional mechanisms which

A

prevent future hybrids from developing

26
Q

Post zygotic barriers: most hybrid offspring do not survive.

A

reduced hybrid viability

27
Q

hybrid offspring are vigorous but sterile.

A

Reduced hybrid fertility

28
Q

the first-generation hybrids are viable and fertile but the offspring of the hybrids are usually sterile.

A

hybrid breakdown

29
Q

There are two main modes of speciation:

A
  • allopatric speciation

- sympatric speciation

30
Q

Geographic isolation may cause a population to become genetically unique as its gene pool is changed by natural selection, genetic drift, or mutation.

A

allopatric speciation

31
Q

Sympatric speciation occurs if a _________________ _______________________ between parents and offspring

A

mutations may result in plant with a different number of chromosomes

32
Q

This is _________________: a multiple number of chromosomes,

A

poly ploidy

33
Q

If a parent cell fails to divide after DNA replication occurs, chromosomes duplicate, then ______________________ ______________________________________________.

A

self fertilize may result in plant with a different number of chromosomes

34
Q

This plant may be incompatible with others (due to the newly increased chromosome number) and considered a

A

distinct species.

35
Q

A farmer sows grain kernels from mixed plants in the wild.

 Some of the plants in the field hybridize and self-fertilize.

A

As a result, many domesticated plants are the result of sympatric speciation

36
Q

The evolution of many diverse species from a common ancestor is ______________________.

A

adaptive radiation

37
Q

An example of adaptive radiation can be found on the Galápagos islands

A

with the 14 different finch varieties considered to have arisen from a common ancestor from the mainland.

38
Q

n speciation,

A

a gradual accumulation of many changes, may account for a new species.

39
Q

speciation is called ________________, explaining how a new species evolved through the gradual accumulation of changes brought about by natural selection.

A

gradualism

40
Q

However, __________________________are found in the fossil record.

A

few transition fossils are found

41
Q

The _______________________ model is a contrasting model of macroevolution.

A

punctuated equalibrium

42
Q

This model proposes that species diverge in _______ ____________________ as a population diverges from the ancestral populations, with little or no change occurring for the remainder of the species’ existence.

A

spurts of relatively rapid change

43
Q

This would account for the relative _______________ ___________________________.

A

rarity of transitional fossils

44
Q

___________________: long periods of little change, or equilibrium punctuated by abrupt episodes of speciation

A

punctual equalibrium model

45
Q

__________________: Slow gradual changes over time

A

gradualist model

46
Q

But, how long exactly is a “punctuation”?

A

A punctuation may involve hundreds of generations.

47
Q

_______________________________changes may have occurred during the existence of a species.

A

both gradual and punctual

48
Q

This means that, in evolutionary time, even a ____________________change may take longer than humans can directly observe.

A

“punctuated”