NOTES # 16: Organic molecules (2 - Weebly
NOTES #31: Evolution and Genetics
Evolution and Genetics
Evolution requires these four things (VSIT):
1. Variation – ______________ between individuals in a _________
2. Selection – some individuals have greater ___________ than others in the _________________ and will _________ better
3. Inheritance – the ________ that result in greater ____________ can be _______________ to offspring
4. Time – many, many ________________ must pass
We can now understand how evolution works better than Darwin ever could. Now we know ________ are the units of _____________, and they are what explain _________________________.
different ______ ( different ____________ ( different ________ = VARIATION!
Genetic variation is studied at the ______________ level.
In genetic terms, evolution is any ___________ in the ___________________________ of alleles in a population.
• the relative frequency of an allele is the number of times that it occurs as a percentage of the total number of alleles in the gene pool
Genetic variation comes from ______ sources:
1. mutations
• does ______ always affect ______________
2. gene shuffling during _____________
• crossing-over introduces new ______________________________
• independent assortment creates new ___________________________
Remember, it is _______________, not _____________ organisms that can _________.
Natural selection is not the only source of evolution.
Genetic drift is the ____________________ in allele frequencies due to _____________________________.
• The founder effect is an example of a bottleneck.
• a small group of individuals starts a new pop-ulation with a different _____________________ from the original population
Coevolution
Certain species that ____________________________ can coevolve. Coevolution occurs when ____________
__________________________________ affects the __________ of another.
Example: Pollinators and plants often coevolve.
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Big Picture: How can we explain evolution in terms of genetics?
When will evolution NOT occur?
The Hardy-Weinberg principle states that allele frequencies in a population will remain constant if and only if the following conditions are met:
1. Mating is __________.
2. Population is _____________________.
3. No ______________ into or out of the pop.
4. No _______________.
5. No ________________________.
THINK
1. What four things does evolution require?
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2. What can cause evolution, other than natural selection? In what kind of populations does this phenomenon occur?
3. What are the main sources of genetic variation?
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