Chapter 3 : Natural Selection Flashcards

1
Q

What is evolution?

A

Change in frequency of individual organisms that differ genetically in one or more traits over time

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2
Q

What does natural selection operate on?

A

Traits (phenotype)

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3
Q

What are traits determined by?

A

Genotype

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4
Q

What are phenotypes controlled by?

A

Gene expression, environmental influence, and interactions of many genes

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5
Q

What is the primary source of genetic variation?

A

Genetic mutation

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6
Q

What is passed on in the process of inheritance?

A

Genes and their mutation

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7
Q

What do some traits cause in relation to fitness?

A

Survival and reproductive advantages

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8
Q

What does the example of the peromyscus polionotus (beach mice) illustrate?

A

Phenotypic variation

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9
Q

What does the a-MSH do to produce eumelanin?

A

It binds to Mc1R

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10
Q

What does the a-MSH produce?

A

Eumelanin (brown)

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11
Q

What does the ASP do to produce phaeomelanin (light)?

A

It blocks the a-MSH

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12
Q

What does ASP produce?

A

Phacomelanin

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13
Q

What does a mutation do to a protein?

A

Changes its shape and function

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14
Q

What can a mutation in the Mc1R gene lead to?

A

It inhibits a-msh binding and therefore alters phenotype frequencies

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15
Q

How does a phenotype that better matches and organisms environment affect them?

A

Higher fitness and higher ability to produce offspring more likely

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16
Q

What level does evolution by natural selection operate on?

A

The population level

17
Q

What does natural selection do to populations over time?

A

Changes the frequencies of phenotypes/genotypes

18
Q

What does fitness mean in terms of evolution?

A

The success of an entity in leaving descendants (their genes and alleles) to the next generation

19
Q

What is another strong driving force in evolution?

A

Random processes like the environment suddenly shrinking

20
Q

What does evolution by natural selection lack?

A

Foresight, meaning that it operates on current conditions and genetic variation

21
Q

What is modern synthesis?

A

The combination of the principles of Mendelian genetics with evolution by natural selection

22
Q

What is the norm of reaction?

A

A curve that represents the phenotype expressed by a given genotype as a function of environmental conditions

23
Q

What is an adaptive trait?

A

Traits that enhance the ability to survive andreproduce in a given environment

24
Q

What is pleiotropy?

A

The ability of a single gene to have multiple effects

25
What is antagonistic pleiotropy?
The same gene that codes for beneficial effects also codes for deleterious effects in other contexts
26
What did Lenski's E.coli experiment show?
27
What are the three conditions of natural selection?
Variation, inheritance, and differential