Week 4 Learning

This week in AP bio we learned about measuring evolution and the Hardy-Weinberg theorem.

Lecture: Measuring Evolution 

• Populations evolve, not individuals
  • Individuals are selected
  • The genetic makeup changes
  • Fitness increases
• Variation
  • An organism has to be more fit than another in order for natural selection to take place.
  • Comes from mutations and sex
  • Mutation= random changes in the DNA
  • Sex= Mixing genes – new arrangements
• Terminology
  • Gene= Determines a trait
  • Allele= A variation of a gene
    • Sexually produced organisms have two alleles
      • Dominant = The showing trait
      • Recessive = Only shows trait if both alleles are recessive
• New Terminology
  • Homozygous= An individual who has two copies of the same allele
  • Heterozygous= Any individual who has one copy of dominant and onerecessive
  • Population= A local group of interbreeding individuals
  • Gene Pool= A collection of alleles in the population
  • Evolution= Change in allele frequency in population
• Five Sources of Evolution
  • Mutation
  • Gene Flow
    • Movement of alleles and their alleles
      • Wind with seeds
      • Migration of animals
      • Reduces differences between populations
      • Modern Travel of humans
  • Nonrandom mating
    • Sexual selection
  • Genetic Drift
    • Chance events
    • Reduces variability
    • Founder effect, Bottleneck
  • Natural Selection

A good visual for Gene Flow:

Hardy- Weinberg Theorem 

p² + 2pq + q²

• p² = BB
• 2pq= Bb
• q² – = bb

Solving steps

1. Write down both equations
2. Identify any given information
3. Don’t mess up squaring decimals
4.  Figure out q²  or q
5. Work your way around the problem

QUESTIONS

• In what real-world situations is the theorem used?
• What would cause allele frequencies to not change?

 

Sources:

https://www.khanacademy.org/science/biology/her/heredity-and-genetics/v/hardy-weinberg