Genetic Drift & Gene Flow Flashcards Preview

AP Biology 2014 > Genetic Drift & Gene Flow > Flashcards

Flashcards in Genetic Drift & Gene Flow Deck (11)
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1
Q

What is genetic drift?

A

Random increase or decrease of alleles (alleles may increase or decrease by chance). In small populations, the effect can be very strong and influence evolution

2
Q

What is the founder effect?

A

A type of genetic drift that occurs when allele frequencies in a group of migrating individuals are (by chance) not the same as the population of origin

3
Q

What is the bottleneck effect?

A

A type of genetic drift that occurs when the population undergoes a dramatic decrease in size

4
Q

What are some examples of causes of the bottleneck effect?

A

Natural catastrophe, predation, or disease. Destructive geological or meteorological events may also contribute

5
Q

What is the movement of individuals between populations and what is the result?

A

Gene flow. The result is the removal of alleles from a population when they leave (emigration) and the addition of alleles when they enter (immigration)

6
Q

What is an example of the founder effect?

A

The Amish community’s large presence of the allele for polydactylism (more than five fingers or toes on a limb). The number of cases for this exceed the number of cases that occur in the world’s remaining population

7
Q

What are the four effects of genetic drift?

A

1). Significant in small populations 2). Allele frequencies change at random 3). Loss of genetic variation within populations 4). Harmful alleles may become fixed

8
Q

What are the three effects of gene flow?

A

1). Reduces the genetic variation between populations 2). Results in two populations combining into a single population with a common gene pool 3). Affects adaptations to local environmental conditions

9
Q

What is an example of gene flow?

A

Adaptational differences between birds born on different parts of an island that carry on throughout life

10
Q

How are humans affecting gene flow?

A

The easier movement of people leads to mating with populations that had never before come in contact. This leads to an exchange of alleles and fewer genetic differences

11
Q

Which form of genetic drift most likely accounts for the relatively high frequency of certain inherited disorders?

A

The founder effect