Class notes
Bio 102 Evolutionary Processes Notes
- Course
- BIO 102
- Institution
- University Of Rhode Island
This is a comprehensive and detailed note on Evolutionary Processes for Bio 102. *Essential Study Material!!
[Show more]
Content preview
Evolutionary ProcessesMonday, February 28, 2022 10:04 AM
• Evolution
○ Change in the genetic characteristics if a population over time
• Change in genetic characteristics
○ Change in allele frequencies within a population
• Allele
○ A particular version of a gene
• Alleles -> genotypes -> phenotypes
○ A and a - alleles (versions of genes) ->
○ AA, Aa, aa - genotypes (combination of all alleles possessed by
individuals ->
○ Phenotypes (observable traits)
• Evolution is a change in allele frequencies of a population over time and it can
be caused by:
○ Natural selection
§ That includes:
□ Balancing
□ Directional
□ Stabilizing
□ Disruptive
○ Genetic drift
§ Causes allele frequencies to change randomly and can lead to loss
of diversity
○ Gene flow
§ Occurs when individuals leave one population, join another, and
breed. Makes allele frequencies more similar between populations
○ Mutations
§ Modifies allele frequencies by continually introducing new alleles
○ Hardy Weinberg Principle
§ A very simplified model can be used to test whether evolution is
acting on a particular gene in a population
§ Gen 1 (diploid) -> gene pool (haploid genes) -> gen 2 (diploid)
§ The hardy Weinberg principle serves as a null hypothesis for
determining whether evolution is acting on a particular gene in a
, determining whether evolution is acting on a particular gene in a
population
§ H0 = evolution is not occurring = hardy Weinberg equilibrium
§ H1 = evolution occurring
§ 5 assumptions of hardy Weinberg principle
□ No natural selection
□ No genetic drift
□ No geneflow
□ No mutation
□ Random mating
§ Two fundamental claims
□ If the frequencies of alleles A1 and A2 in a population are given
by p and q, then the frequencies of genotype A1A1, A1A2, and
A2A2 will be given by p2, 2pq, and q2 for the generation after
generation
□ When alleles are transmitted, their frequencies do not change
over time. For evolution to occur, some other factor (s) must
come into play
§ p2 + 2pq + q2 = 1 <- hardy-Weinberg equation
§ Process overview
□ Observed genotype frequencies -> A1A1, A1A2, A2A2
□ Observed allele frequencies -> A1, A2
□ Expected -> A1A1 = p^2, A1A2 = 2pq, A2A2 = q^2
§ Hardy-Weinberg equilibrium: how to calculate frequencies
□ p= frequency of the dominant allele in the population
□ q = frequency of the recessive allele in the population
□ p2 = percentage of homozygous dominant individuals
□ q2 = percentage of homozygous recessive individuals
□ 2pq = percentage of heterozygous individuals
□ p2 + 2pq + q2 = 1
□ p+q=1
• Nonrandom mating
○ Inbreeding: Mating between two relatives
§ Most intensively studied form of nonrandom mating
○ Two Fundamental points
§ Inbreeding increases homozygous
§ Inbreeding itself does not cause evolution because allele
frequencies do not change the population as a whole
• How does inbreeding influence evolution?
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anyiamgeorge19. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.29. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
53340 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now