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BIOL 1105 > 21: Mechanisms of Evolutionary Change > Flashcards

21: Mechanisms of Evolutionary Change Flashcards

Module 4, Lesson 4 (74 cards)

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1
Q

Generally, evolution is defined as…

A

A change in a population of organisms over time

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2
Q

In biology, evolution is defined as…

A

A change in allele frequencies in a population over time

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3
Q

True or false:

Individuals can evolve.

A

False

Evolution only occurs at the population level

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4
Q

The presence of different alleles in a population is called…

A

Genetic variation

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5
Q

True or false:

Genetic variation is necessary for evolution to occur.

A

True

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6
Q

____ can also be defined as the result of any process that changes the genetic composition of a population over time.

A

Evolution

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7
Q

List four areas of variation that can be observed in a population.

A
  1. Morphology
  2. Genes
  3. Proteins
  4. Genomes
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8
Q

____ occurs when a population has individuals with many different alleles for the same gene, resulting in a range of phenotypes.

A

Polymorphic variation

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9
Q

The ____ is the genetic constitution or makeup of an individual.

A

Genotype

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10
Q

The ____ is an individual’s apparent characteristics.

A

Phenotype

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11
Q

A primary focus of evolutionary biology is understanding….

A

The mechanisms of evolution

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12
Q

List five mechanisms of evolution.

A
  1. Mutation
  2. Gene flow
  3. Genetic drift
  4. Selection
  5. Nonrandom mating
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13
Q

True or false:

Mechanisms of evolution can act over both short and extremely long timescales.

A

True

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14
Q

A ____ is any change in the base sequence of DNA.

A

Mutation

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15
Q

The ultimate source of genetic variation is…

A

Mutation

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16
Q

True or false:

Mutations are the primary cause of changes in allele frequency within a population.

A

False

They are extremely rare, so the other processes play a bigger role

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17
Q

The movement of alleles from one population to another is called…

A

Gene flow

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18
Q

List two ways in which gene flow can occur.

A
  1. An organism moves to a new location
  2. An organism mates with a member of a different population
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19
Q

Gene flow can result in…

(two)

A
  1. The introduction of new alleles into a population
  2. A shift in allele frequencies
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20
Q

A change in allele frequencies due to “sampling error” (random chance) is called…

A

Genetic drift

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21
Q

Genetic drift has the greatest effect on ____ populations.

A

Small

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22
Q

True or false:

With enough time, genetic drift alone can cause substantial changes in allele frequencies.

A

True

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23
Q

As a result of genetic drift, two small, isolated populations may…

A

Differ genetically even without natural selection

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24
Q

List two results of genetic drift.

A
  1. Some alleles will build up (fixation) and others will be lost.
  2. The frequency of heterozygotes declines
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25
The ____ occurs when a new population is established by a small number of individuals.
Founder effect
26
A population that experiences founder effect will...
Have a different allele frequency compared to the parent population
27
What happens if a founding individual carries a rare allele?
The new population has a higher frequency of that allele than the original population
28
The founder effect is common in ____, because generally only a small number of individuals were involved in colonization.
Island populations
29
The ____ occurs when a population loses genetic variation due to a drastic reduction in size.
Bottleneck effect
30
In both the founder effect and the bottleneck effect, the alleles found in the new population...
May not represent all the alleles found in the original population
31
The bottleneck effect is often a problem in...
Populations of endangered species
32
# True or false: Even if the population of a critically endangered species rebounds, the species will still have lost significant genetic variation.
True
33
The number of offspring that an organism leaves behind is affected by...
Phenotype and behavior
34
Charles Darwin suggested ____ as the mechanism of evolution.
Natural selection
35
List three main points of Darwin's theory of natural selection.
1. More individuals of a species are born than can possibly survive 2. Individuals that have profitable variations are more likely to survive and reproduce 3. Any selected variation will propagate its modified form
36
List three conditions that must be met for natural selection to occur.
1. Variation in individuals 2. Differences in rates of survival and reproduction 3. Heritability of variations
37
Individuals with that are more successful at surviving and reproducing are said to have higher...
"Fitness"
38
# True or false: Natural selection states that survival and reproduction are random.
False
39
According to natural selection, individuals with more favorable variations will...
Be better at surviving and reproducing (will be naturally selected)
40
____ occurs when environmental conditions affect which individuals produce the most offspring.
Natural selection
41
The outcome of natural selection depends on ____ and ____.
Fitness and allele frequency
42
# True or false: A strong fitness effect can act quickly even with small differences in allele frequencies.
True
43
# True or false: Evolutionary forces act independently of one another.
False
44
Evolutionary forces can work ____ or ____.
Together or in opposition
45
____ and ____ can counter selection.
Mutations and genetic drift
46
Gene flow can either promote or prevent...
Evolutionary change
47
Selection may be hindered if less-favored alleles...
Are constantly being introduced
48
____ occurs when humans select for certain characteristics in a population.
Artificial selection
49
Artificial selection is also sometimes called...
Selective breeding
50
# True or false: The terms "evolution" and "natural selection" can be used interchangeably.
False
51
____ is the process that leads to evolution.
Natural selection
52
____ is the historical record of change through time, and the outcome of natural selection.
Evolution
53
Evolutionary mechanisms work together to change...
Allele frequencies over time
54
In small populations, genetic drift can lead to the ____ of a mutation.
Loss
55
Natural selection can cause elimination or promotion of a...
Phenotype (and the corresponding mutation)
56
The combination of survival, mating success, and the number of offspring per mating is referred to as...
Fitness
57
Natural selection is heavily influenced by the...
Environment
58
# True or false: It is possible that a trait might be selected for in one habitat and selected against in another.
True
59
# True or false: It is possible to observe natural selection occuring.
True
60
A common trait used to study natural selection is...
Guppy color variation
61
Guppy populations in ____ environments display more spots and brighter colors after several generations.
Low-predator
62
Guppy populations in ____ environments display dull colors after several generations.
Predator-containing
63
____ from predators plays a role in guppy coloration.
Natural selection
64
The ____ seeks to explain why the original proportions of genotypes remain constant in a population over time.
Hardy-Weinberg Principle
65
Hardy and Weinberg were led to investigate why populations retain multiple alleles by...
The rediscovery of Mendel's work
66
According to the Hardy-Weinberg principle, what five conditions must be met for the proportions of genotypes in a population to remain constant?
1. No mutation takes place 2. No genes are transferred to or from other sources 3. Mating is random 4. The population size is very large 5. No selection occurs
67
When the proportion of genotypes does not change, a population is said to be in...
Hardy-Weinberg equilibrium
68
The Hardy-Weinberg principle is used to detect...
Whether evolutionary processes are underway in a population
69
If no evolutionary forces are acting on a population, it will...
Remain in Hardy-Weinberg equilibrium
70
For a population that is not in equilibrium, the type of evolutionary processes taking place can be studied by...
Examining the changes in allele frequencies
71
List three areas that stand to benefit from increased understanding of evolution.
1. Medicine 2. Conservation 3. Agriculture
72
How does understanding evolution benefit the medical field? | (two items)
1. Studying antibiotic resistance 2. Understanding evolution of infectious diseases
73
How does understanding evolution benefit conservation efforts? | (four items)
1. Defining species of conservation concern 2. Understanding problems of small populations 3. Understanding how species go extinct 4. Finding ways to prevent extinction
74
How does understanding evolution benefit agriculture? | (three items)
1. Improving artifical selection 2. Studying pesticide resistance 3. Creating genetically modified organisms

BIOL 1105 (26 decks)

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