IB Biology Topic D4.1.11 Changes in Allele Frequency in the Gene Pool Revision Notes (HL)

IB Biology Topic D4.1.11 Changes in Allele Frequency in the Gene Pool Revision Notes (HL) | RevisionDojo

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Four Processes Change Allele Frequencies in a Gene Pool

Evolution at the population level is a change in allele frequencies, and four processes can cause it.
They are natural selection, mutation, genetic drift, and gene flow.

Note

Only natural selection is biased by fitness, so it is the only process that builds adaptation.
The other three can spread a harmful allele as easily as a helpful one.

Natural Selection: The Only Process That Builds Adaptation

Selection raises the frequency of alleles linked to higher reproductive success and lowers those linked to lower success.
While the selection pressure stays the same, the favoured allele keeps climbing toward fixation, so the change is directional.

Mutation: The Source of New Alleles

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Four Processes Change Allele Frequencies in a Gene Pool

Evolution at the population level is a change in allele frequencies, and four processes can cause it.
They are natural selection, mutation, genetic drift, and gene flow.

Note

Only natural selection is biased by fitness, so it is the only process that builds adaptation.
The other three can spread a harmful allele as easily as a helpful one.

Natural Selection: The Only Process That Builds Adaptation

Selection raises the frequency of alleles linked to higher reproductive success and lowers those linked to lower success.
While the selection pressure stays the same, the favoured allele keeps climbing toward fixation, so the change is directional.

Mutation: The Source of New Alleles

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(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic D4.1.11: Changes in Allele Frequency in the Gene Pool Notes

Four Processes Change Allele Frequencies in a Gene Pool

Natural Selection: The Only Process That Builds Adaptation

Mutation: The Source of New Alleles

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Four Processes Change Allele Frequencies in a Gene Pool

Natural Selection: The Only Process That Builds Adaptation

Mutation: The Source of New Alleles

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics