Genetic Drift

What is genetic drift?

• the changes in allele frequencies (genes) ,in a population, happening due to random events/circumstances.

• It is an example of primary succession

• Genetic drift are different organisms in a population due to inherited traits from their parents

• It is part of symbiotic relationships such as mutualism, commensalism, parasitism

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Genetic drift is change in the allele frequency of a population due to...

• random chance
• natural selection
• non-random mating (sexual selection)
• artificial selection

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All of the genetic information found in a population.

• population

• genetic drift

• evolution

• gene pool

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What characteristic did Darwin observe about the finches on the Galapagos Islands?

• Their feathers

• Genotypes

• Their beaks

• Their body sizes

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Which of the following is an example of the bottleneck effect?

• Cheetah populations reach their lowest levels with reduced diversity and as they rebound are so genetically similar they appear to be inbred.

• Affected individuals with blue skin can trace their ancestry back to one of the first settlers in the region.

• The environment of a fox population changes and over time foxes who are white survive and pass on their genes to their offspring.

• Humans choose two dogs they like the characteristics of and breed them together.

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Happens only in small populations, and is the change in the frequency of a gene variant (allele) in a population due to random sampling of organisms.

• Extinction
• Genetic Drift
• Bottleneck Effect
• Founder Effect

Hunting reduced the population size of the northern elephant seal to as few as 20 individuals at the end of the 19th century. Their population has since rebounded to over 30,000, but much have less genetic variation than a population of southern elephant seals that were not intensely hunted. How is the lack of genetic variation related to the hunting episodes of the 1800's?

• Genetic Drift Occurred/Genetic Bottleneck: the few individuals left behind were the seals that passed on the specific gene pool.

• Genetic Drift Occurred/Founder Effect: the few individuals left behind were the seals that passed on the specific gene pool.

• Natural Selection Occurred/Survival of the Fittest: only the strongest northern elephant seals survived in the 1800's and that restricted gene pool exists today.

• Adaptation Occurred: Some seals were able to adapt to the hunting environment and they survived to pass on their genes.

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In Genetic Drift, both Genetic Bottleneck and the Founder Effect, the end result is

• less genetic diversity withing a population

• a smaller population size

• a new gene pool created by random chance

• a population of organisms that are best fit for their environment

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Which statement is part of Darwin’s theory of evolution by natural selection? 

• More offspring are produced than can possibly survive.
• The organisms that are the fittest are always largest and strongest. 
• The number of offspring is not related to fitness.
• Acquired characteristics that are inherited are the cause of evolution.

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Which of the following is a factor in natural selection?

• Individuals of species compete with one another to survive.
• All species are genetically diverse.
• Individuals better able to adapt to changes leave more offspring.
• All are correct 

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