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Mind Map by the.pink.ninja60, updated more than 1 year ago
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Created by the.pink.ninja60
over 10 years ago
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Biology Midterm 2
- The Hardy-Weinberg Principle
- Regarding Entire population, not just individuals.
- When alleles are transmitted via meiosis and random
combination of gametes, their frequencies do not change
over time. For evolution to happen, some other factor(s)
must come into play.
- 5 assumptions must be met:
- 1) No natural selection
- 2) No genetic drift or random
allele frequency changes
- 3) No gene flow
- 4) No Mutation
- 5) Random mating
with respect to gene.
- 1) No natural selection
- 5 assumptions must be met:
- When alleles are transmitted via meiosis and random
combination of gametes, their frequencies do not change
over time. For evolution to happen, some other factor(s)
must come into play.
- p2 + 2pq +q2 = 1
- Serves as null
hypothesis when
biologists want to test
whether on of the
evolutionary processes
is at work.
- Regarding Entire population, not just individuals.
- Natural Selection
- Can only occur if heritable
variation exists.
- Alleles for favoured phenotype increse in frequency
while others decrease. Result is evolution.
- Evolution occurs when
heritable variation leads to
differential success in survival
and reproduction (fitness).
- Evolution occurs when
heritable variation leads to
differential success in survival
and reproduction (fitness).
- Types of Natural Selection:
- 1) DIrectional Selection
- Average phenotype of
population changes in
one direction.
- Tends to reduce genetic diversity.
- If continues over time, favoured
alleles eventually approach
fixation (1.0 frequency) and
disadvantageous alleles
approach loss.
- **Loss/fixation may not always occur.
- **Loss/fixation may not always occur.
- Tends to reduce genetic diversity.
- Average phenotype of
population changes in
one direction.
- 2) Purifying Selection
- Lowers frequency or even eliminates deleterious alleles.
- ***Associated with the other types of selection.
- ***Associated with the other types of selection.
- Occurs when
disadvantageous alleles
decline in frequency.
- Lowers frequency or even eliminates deleterious alleles.
- 3) Stab
- 1) DIrectional Selection
- Can only occur if heritable
variation exists.
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