Biology 100 Unit 13 Flashcards

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1
Q

________________’s influential book entitled On the Origin of Species by Means of Natural Selection was published on November 24,1859.

A

Charles Darwin

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2
Q

Over generations, individuals with the best functioning traits are consistently selected, _____________ ____________ are produced.

A

evolutionary adaptations

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3
Q

Darwin’s research was nontraditional because he suggested that ___________________________

A

the Earth was relatively old and populated by all species being related to each other.

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4
Q

In his theory, he predicted _____________________to have existed between species

A

numerous intermediates

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5
Q

Darwin’s views were

A

embraced by some, and rejected by others

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6
Q

In December 1831, Darwin (age 22) left Great Britain as the on board naturalist of the ____________

A

HMS Beagle.

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7
Q

Darwin realized that the distribution of species in the _________________ was unusual.

A

galapagos islands

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8
Q

It was apparent to him that many Galápagos species resembled those found in South America, but showed some____________________

A

variation

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9
Q

Darwin was strongly influenced by the writings of geologist ____________, who promoted the idea of an ancient Earth.

A

Charles Lyell

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10
Q

What two things was Darwin convinces of

A

– the Earth was very old, had been shaped by slow processes and continues to change even today.
– just as earth changed, or evolved, so could the organisms that lived upon it, because they responded to their environment

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11
Q

– the Earth was very old, had been shaped by _____

___________, and continues to change even today.

A

slow processes

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12
Q

just as earth changed, or evolved, so could the organisms that lived upon it, because they

A

responded to their environment

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13
Q

In The Origin of Species, Darwin emphasized two main points.

A

– All organisms inhabiting Earth today are derived from ancestral species that may have looked differently (descent with modification).
– The mechanism by which this was accomplished is natural selection
– As organisms reproduce, they can have a variety of offspring. Those offspring best fit for their environment are most fit to survive and reprorduce

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14
Q

What are the 4 evidences used to support evolution

A

fossils, biogeography, comparative anatomy, and molecular biology

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15
Q

are remnants of organisms that lived in the

past that have been turned to stone.

A

fossils

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16
Q

fossils can include

A

plants, animals, impressions, bones, & soft tissues.

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17
Q

______________ is where fossilization is most likely.

A

sedementary rock

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18
Q

Fossils are often used to

A

compare anatomy with extinct organisms with extant ones

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19
Q

interpreted as chronology of fossils embedded in rock layers of different ages.

A

fossil record

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20
Q

Fossil records are used to

A

show that organisms appeared in a historical sequence.

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21
Q

Older more primitive organisms at the_______

A

bottum of fossils

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22
Q

________more advanced organisms at the top of the fossil

A

newer

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23
Q

is the study of the geographic distribution of species.

A

biogeography

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24
Q

Darwin observed Galápagos birds that resembled those in South America. The resemblance infers that

A

they shared a common ancestor.

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25
Q

Natural selection then explains that organisms

A

must have specific characteristics to live in a particular environment

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26
Q

is the comparison of body structure between different species.

A

comparative anatomy

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27
Q

is the similarity of structures due to common ancestry

A

homology

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28
Q

Ancestral structures became

A

modified to undergo a new function

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29
Q

__is the similarity of structures based on function, but does not share common ancestry.

A

analogy

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30
Q

Forelimbs of mammals are constructed from the same skeletal elements, because they are interpreted as sharing a common ancestor they are considered _____________

A

homologous structures

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31
Q

is the comparison of structures that appear similar during the development of different organisms

A

Comparative embryology

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32
Q

During early embryology, some vertebrates look similar, implying they have very similar features, which may indicate ______________________.

A

common ancestry

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33
Q

is also used to show evolutionary relationships among species.

A

Molecular biology of organisms

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34
Q

can be used to determine how distantly (or closely) organisms are related.

A

DNA sequence

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35
Q

The more similar one’s DNA is to an organism,

A

the more likely that they are closely related

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36
Q

The less similar one’s DNA is to an organism,

A

they are more likely distantly related.

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37
Q

The similarity between human and chimpanzee DNA is __________.

A

98%

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38
Q

This is the most similar genetic match of humans with any species.

A

The similarity between human and chimpanzee DNA

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39
Q

Evolutionary biologists indicate that the genetic match of humans with any species. is due to

A

a close evolutionary relationship.

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40
Q

Darwin’s Galápagos ————re an example of adaptive evolution as a result of natural selection.

A

s finches a

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41
Q

how many finches are there

A

14

42
Q

the __________ shape of a finches favors certain ___________

A

beak shape, certain enviroments

43
Q

All the individuals in a population have

A

slightly different characteristics

44
Q

Much of this individual variation is______________, and passed down from generation to generation

A

heritable

45
Q

Individuals with less reproductive success die,

therefore they do _______________.

A

not reproduce

46
Q

Only those individuals with traits best suited for their environment,_________________ _leaving a greater number of offspring.

A

are more likely to survive, and reproduce,

47
Q

The genes of individuals with traits suited for their enviroment that are favored by this process (“selected for”) _______________in the population than genes of individuals not favored (“selected against”).

A

will occur in greater frequency

48
Q

Examples of natural selection we are observing right now include
– Pesticide resistance in insects

A

Insects with a resistance to pesticides, will be the ones more likely to survive and reproduce.

49
Q

Consistent use of antibiotics can select for __________ strains of bacteria that are difficult to treat. (__________

A

antibiotic resistant MRSA

50
Q

is a group of individuals of the same species living in the same area at the same time.

A

A population

51
Q

Because variance amongst individuals must be present to select from, ______________are the smallest biological unit that can evolve.

A

populations

52
Q

___________________ investigate the fate of populations as evolutionary units.

A

population gentisits

53
Q

Tracking the genetic makeup of populations over time allows us to determine whether

A

a population is evolving and how fast it is changing.

54
Q

In genetic variation studies, Although there is a lot of variation among individuals of a population differences in ___________________ are what is looked at.

A

genetic (heritable) components

55
Q

Mutations are random ________________of an organism.

A

changes in DNA

56
Q

Most mutations are ______________, but sometimes they are

considered to be beneficial.

A

deleterious

57
Q

shuffles and distributes genetic material during meiotic divisions.

A

Sexual recombination

58
Q

DNA containing these mutations can then be passed

A

from a parent to an offspring

59
Q

includes all versions (alleles) of all genes in all

individuals making up a population.

A

the gene pool

60
Q

What is the gene pool?

A

is the collective genome of the population.

61
Q

in a gene pool occur at certain frequencies.

A

alleles

62
Q

can be symbolized by p for the relative frequency of the dominant (expressed) allele in the population and q for the frequency of the recessive (hidden) allele in the population.

A

p+q=1
p=dominant
q=recessive

63
Q

These symbols are represented in the Hardy Weinburg equilibrium

A

p^2+2pq+q^2

64
Q

p^2

A

homozygous dominant

65
Q

2pq

A

heterozygotes

66
Q

q^2

A

homozygous recessive

67
Q

The Hardy-Weinberg equation adds up all of the ____________ in a population and is used to determine expected ______________ of the next generation.

A

genotypes, phenotypes

68
Q

If the Hardy-Weinberg equation is in equilibrium, this describes a ____________________ that is in genetic stasis (not changing over time).

A

non-evolving population

69
Q

When the Hardy –Weinberg equation is not in equilibrium, the allele frequencies continually change over time, and the population is undergoing small scale evolution called ____________________.

A

microevolution

70
Q

Allele frequency
P+Q=1
What is the formulas for p and q?

A

p  number of dominant alleles for a given gene in a population/ sum of totalalleles for a given gene in the population

q  number of recessive alleles for a given gene in a population /sum of totalalleles for a given gene in the population

71
Q

If a locus has two alleles, W and w, there could be three

A

possible genotypes: WW, Ww, and ww.

72
Q

 Imagine that there are two alleles in a blue-footed booby population, W and w.
– Uppercase W is a dominant allele for a nonwebbed booby foot.
– Lowercase w is a recessive allele for a webbed booby

A

Consider the gene pool of a population of 500 boobies. – 320 (64%) are homozygous dominant (WW).
– 160 (32%) are heterozygous (Ww).
– 20 (4%) are homozygous recessive (ww).
– p = 80% of alleles in the booby population are W. – q = 20% of alleles in the booby population are w.

73
Q

The frequency of all three genotypes must be

A

100% or 1.0.

74
Q

The Hardy-Weinberg equation that can test if a population is evoloving

A

p2 + 2pq + q2 = 100% = 1.0

75
Q

What about the next generation of boobies?

A

-The probability that a booby sperm or egg carries W = 0.8 or 80%
________.
– The probability that a sperm or egg carries w = 0.2 or 20%
– The genotype frequencies will remain constant generation after generation unless something acts to change the gene pool.

76
Q

is measured by changes in allele frequency in a population.

A

Microevolution

77
Q

Mechanisms of microevolution

A

– genetic drift
– gene flow
– mutations

78
Q

_______________is a change in the gene pool of a small population due to chance.

A

genetic drift

79
Q

– is an example of genetic drift.
– results from a drastic reduction in population size. and therefore a reduction in genetic variation
because this limits the possible genes to select from

A

The bottle neck effect

80
Q

the bottle neck effect – is an example of genetic drift.
– results from ________________________________________
because this limits the possible genes to select from

A

a drastic reduction in population size. and therefore a reduction in genetic variation

81
Q

The ______________ is genetic drift in a new colony.

A

the founder effect

82
Q

It explains why certain unusual alleles (such as genetic disorders among humans) are expressed more frequently in populations founded by only few individuals than in the original, large population.
– Founding populations of Galapagos organisms carried only a small, random subset of mainland population genomes.

A

Their allele frequencies therefore were different from that of mainland populations, and this allowed rapid diversification.

83
Q

Tristan da Cunha is the world’s most remote inhabited island.
– In 1815, fifteen British settlers colonized the island, one of whom carried the recessive allele for an eye disease (retinitis pigmentosa).

A

Example of the founder effect

– In the 1960s, some decedents still living on the island, still had the eye disease.

84
Q

When populations regularly or irregularly exchange genetic material, this is called ________________.

A

gene flow

85
Q

The influx of genetic material from other populations will reduce

A

the genetic differences between populations.

86
Q

______________ are permanent changes in an organism’s genome.

A

mutations

87
Q

A single mutation in a single organism ordinarily will not have an impact on a large population since most mutations are

A

lethal.

88
Q

A mutation that is beneficial ___________________, however, can make the difference between survival and death.

A

during periods of environmental stress

89
Q

n those conditions, the mutation may______________________________ in the population, favoring those organisms in a population which carried that allele.

A

significantly alter the allele frequencies

90
Q

_________________is the contribution an individual makes to the gene pool of the next generation relative to contributions of others within that population.

A

relative fitness

91
Q

Genes are contributed to the next generation

A

through offspring.

92
Q

The number of offspring is a way to determine

zero offspring=

A

fitness; zero fitness

93
Q

During ___________________the phenotype of a population is shifted.

A

directional selection

94
Q

directional selection type of selection favors a more __________shifting alleles in a population

A

extreme phenotype,

ex: Mice

95
Q

during ______________________both extremes of phenotype are favored.

A

disruptive selection

96
Q

disruptive selection : _______________ is not advantageous and its frequency becomes reduced.

A

The intermediate phenotype

97
Q

During ___________________the variation of a particular trait becomes limited.

A

stabilizing selection

98
Q

If the extreme trait values are not beneficial, then the _______________________

A

itermediate is selected/ mean value is selected for.

99
Q

– is a form of natural selection

– in which individuals with certain characteristics are more likely than other individuals to obtain mates.

A

sexual selection

100
Q

In many animal species, males and females show distinctly different appearances, called ____________ ________________.

A

sexual selection

101
Q

Intrasexual selection (within the same sex) involves competition for ___________________

A

mates, usually by males.