Evolution of Populations

1
Evolution of Populations

• Genes and Variations

2
Genetic Variation and Gene Pools

• Variation is studied in populations
• Gene Pool consists of ALL genes, including
  different alleles (ex R and r)
• Relative Frequency number of times an allele
  occurs in a pool
• Example - B (black fur)is at 40 frequency and b
  (brown fur) is at 60.
• Why is Black Fur (B)more common if it is only
  40 of the alleles?

3
Evolution is the change of frequency of the
alleles!

• If the numbers change over time, then the
  population is evolving.
• You try it The gene for white moths is W, and
  for black moths is w.
• What do you think the original percentages were
  before the industrial revolution?
• What about after?
• Are they evolving?

4
How do we get variation?

1. Mutation change in DNA sequence, some are good
   and some can be bad for the species
2. Gene Shuffling sexual reproduction and crossing
   over gives a new set of DNA each time we reproduce

5
Different Phenotypes

• Some traits are simple and some are complex ex
  widows peak is caused by a single gene
• Single Gene Trait has 2 alleles only
• Polygenic Traits 2 or more genes control the
  outcome
• This leads to more phenotypes and variation. Ex
  How many shades of eye color are their?