LAB:Variation in a Species

1
LABVariation in a Species

• What is the purpose of Part 1?
• (Measuring Pumpkin seeds)

• There is variation in size in Pumpkin plants.
  Variation can be measured.

2
LABVariation in a Species

• What is the purpose of Part 2?
• (Calculate how long it takes pumpkin plants to
  take over the Earth)

• There are reasons to explain why pumpkin plants
  have not ever taken over the Earth

3
LABVariation in a Species

• What is the purpose of Part 3?
• (Effect of predators on sweet cute Bonitos)

• There are reasons to explain why the population
  of bonitos on one island look different from
  bonitos on another island

4
What is a species?

• A group of living things that

• are similar,

• and can breed together in nature

• to produce fertile offspring.

5
What is a population?

• A group of living things that

• belong to the same species,

• live in the same area,

• and can reproduce together.

6
What is a gene pool?

• The total collection of genes in a population at
  any one time.

7
Hardy Weinberg

• What is allele frequency?

• 1908 Hardy and Weinberg invented the term
  allele frequency to describe the percentage of
  dominant and recessive alleles found in a
  populaton.

8
Hardy Weinberg

• How is allele frequency measured?

• Example a lizard population might have the
  following allele frequency for the alleles F and
  f
• FF 0.64 (64)
• Ff 0.32 (32)
• ff 0.04 (4)

9
Hardy Weinberg

• What is genetic equilibrium?

• 1908 Hardy and Weinberg invented the term
  genetic equilibrium to describe a population in
  which the frequency of alleles stays the same
  from one generation to the next.

10
Hardy Weinberg

• How was genetic equilibrium measured?

• Hardy-Weinberg equations
• p2 2pq q2 1
• p q 1

11
Hardy Weinberg

• Hardy-Weinberg Equations

• Where p2 is the frequency of homozygous dominant
  individuals

• Where 2pq is the frequency of heterozygous
  individuals

• Where q2 is the frequency of homozygous recessive
  individuals

12
Hardy Weinberg

• What causes genetic equilibrium?
• There must be.

• A large population

• Members mating at random

• No mutation

• No migration
• No natural selection

13
Hardy Weinberg

• What can cause allele frequency to change?

• Migration (also called gene flow)

• Mutation

• Mate selection (non-random mating)

• Predators, disease, famine, drought, storms,
  accidents.