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Ecology and Evolution Unit 1 & 2 > Unit 1: Mechanisms Evolution > Flashcards

Unit 1: Mechanisms Evolution Flashcards

https://quizlet.com/661802042/intro-to-evolution-flash-cards/

1
Q

What processes cause evolution?

A
  1. Natural selection
  2. Genetic drift
  3. Migration
  4. Mutation
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2
Q

What is Natural Selection?

A
  1. reproduction of individuals with favorable genetic traits that survive environmental change because of those traits, leading to evolutionary change
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3
Q

What is Variation?

A

genetic differences among individuals in a population

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4
Q

Who are Peter and Rosemary Grant?

A

Study Darwin’s finches on the Galapagos Islands and have measured evolution by natural selection over short time scales

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5
Q

What are the 4 Postulated of Natural Selection?

A
  1. Variation exists among individual organisms in a population
  2. Some of that variation is heritable
  3. Survival and reproduction success is variable
  4. Individuals best able to survive and reproduce is not a random sample
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6
Q

Explain Postulate 3 of Natural Selection.

A
  • Populations produce more offspring than can survive
  • Resource limit populations, lead to struggle for existence
  • Some individuals reproduce more than others
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7
Q

What is a Polygenic Trait?

A

controlled by multiple genes
(ex: expressions of Bmp4 which effects width and depth)

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8
Q

What is Adaptation?

A

heritable traits or behavior in an organism that aids in its survival and reproduction in its present environment
Note: that environments change, and thus the trait that is adaptive can also change

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9
Q

What is Heredity?

A

the transmission of genetic characteristics from parents to offspring

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10
Q

What is heritability?

A

the fraction of population variation that can be attributed to its genetic variance

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11
Q

What did Gregor Mendel discovery?

A

(1822-1884)
- Each parent passes a combination of discrete ‘factor’ (alleles or genes)
- Each gamete carries only one factor
-Factors segregate independently during gamete formation
- Dominant and recessive factors

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12
Q

Was Gregor Mendel’s work known by Wallace and Darwin?

A

Yes

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13
Q

What is Evolutionary Fitness?

A

individual’s ability to survive and reproduce

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14
Q

What is Relative Fitness?

A

individual’s ability to survive and reproduce relative to the rest of the population

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15
Q

What is Selection Pressure:

A

environmental factor that causes one phenotype to be better than another (abiotic or biotic)

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16
Q

Who studies Genetic basis of adaption and Morphology & behavior in mice?

A

Hopi Hoekstra

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17
Q

Name the types of Selections.

A
  1. Stabilizing selection
  2. Directional selection
  3. Diversifying selection
  4. Frequency-dependent selection
  5. Negative free-dependent selection
  6. Sexual selection
  7. Artificial selection
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18
Q

In Stabilizing selection, Phenotype higher AND lower than the mean has __________.

A

low fitness

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19
Q

In Stabilizing selection, mean __________________.

A

stays the same

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20
Q

In Stabilizing selection, Genetic variation is _______.

A

reduced

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21
Q

In Directional selection, Phenotype higher OR lower than the mean has _______.

A

highest fitness

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22
Q

In Directional selection, the mean move in the direction with the ______ fitness.

A

higher

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23
Q

In Directional selection, Genetic variation is _______.

24
Q

In Diversifying selection, Phenotype higher AND lower than the mean has the ____ fitness

25
In Diversifying selection, the mean ___________________.
COULD stay the same
26
In Diversifying selection, Genetic variation is ________.
increased
27
Positive frequency-dependent selection is understood to be
stabilizing selection
28
What is Negative frequency-dependent selection?
is a type of diversifying selection when considered over multiple generations
29
In Negative frequency-dependent selection the ____ type has a higher fitness.
rare
30
In populations with sexual dimorphism, the ____ are typically more decorated, larger , or stronger.
males
31
What is Sexual Selection?
selection that favors phenotypes that increase ability to obtain or choose good mate
32
Who does Sexual Selection often act on? And Why?
Males, because of fundamental asymmetry of sex
33
What is Fundamental Asymmetry of Sex?
females invest more in their offspring than do males
34
What does Sexual Selection predict?
females should be choosy, males compete with each other
35
What is Artificial Selection?
Deliberate manipulation of fitness by humans through selective breeding
36
What type of Selection molds domesticated plants and animals?
Artificial Selection?
37
What leads to genetic drift?
sampling error in sexual reproduce
38
Individuals are ______ & produce gametes that are ______.
diploid (2n), haploid (n)
39
Gametes contain _________ of an individual's alleles
random sampling (50/50 probability for each allele)
40
Allele frequencies therefore ______ across generations.
"drift"
41
The magnitude of the drift is INVERSELY related to the population size:
large population size = low genetic drift small population size = high genetic drift
42
Genetic Drift can lead to _____ or ____ of alleles, which reduces genetic diversity.
loss (freq = 0), fixation (freq = 1)
43
What causes Genetic Drift?
1. Bottleneck effect (sudden reduction in population size) 2. Founder Effect (dispersal over a barrier)
44
Genetic drift affects the whole genome and is random with respect to fitness.
True
45
Genetic drift will usually result in a _______ in average fitness.
reduction
46
What does Migration (gene flow) do to populations on a genetic scale?
makes populations more similar genetically
47
Migration can _____, ____, or have ____ on fitness & genetic diversity
increase, decrease, no effect
48
What are Mutations?
changes to DNA & ultimate source of new alleles
49
Mutations ____ genetic diversity.
increase
50
Mutation are generally random.
True
51
List Mutations effects on Phenotypes.
1. None (neutral) 2. Changes in protein or protein expression 3. Absence of protein
52
Since most organisms are well adapted to their environment, mutation in coding/regulatory regions most often _____ fitness (deleterious)
lower
53
Which mutations are heritable?
only germ lines
54
(Evolutionary Impacts) low rates = ____
slow changes
55
New mutations have very little effect on allele frequencies.
True, the frequency of novel allele is 1/2n
56
What does the fate of new alleles depend on?
1. Natural Selection 2. Genetic Drift 3. Migration

Ecology and Evolution Unit 1 & 2 (12 decks)

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