Evolution Lab Module Face-to-Face

Big Idea:
- Descent with modification by natural selection explains evolution and underpins the unity and diversity of life.
Learning Objectives:
- Calculate allelic and genotypic frequencies.
- Understand and calculate Hardy-Weinberg Equilibrium.
- Construct and interpret graphs and tables on allele and genotype frequencies over time.
- Analyze how natural selection, gene flow, and genetic drift alter allele frequencies.
Overview Before Lab:
- Thoroughly read the laboratory module.
- Watch the instructional video.
- Complete the pre-lab quiz in Canvas.
During Lab:
- Answer questions related to experiments.
- Complete data tables.
- Create line graphs of the data.
After Lab:
- Upload post-lab assignment to Canvas.

Theory of Evolution:
- Describes genetic changes in populations over time.
Natural Selection:
- Organisms with favorable traits survive and reproduce more than those without.
- Adaptive traits improve fitness, resulting in increased offspring in subsequent generations.
- Major force driving genetic change and evolution of new species.
- Charles Darwin is credited; Alfred Russell Wallace proposed similar ideas.
Genetic Change Measurement:
- Simulations using inanimate objects help observe genetic changes through calculated frequencies.
- Genotypic Frequency: Number of individuals with a specific genotype divided by the total.
- Allelic Frequency: Number of specific alleles divided by the total in the population.

Example data for B locus genotype frequencies:| Genotype | Number of Individuals | Genotypic Frequency | Allele | Allelic Frequency ||----------|----------------------|---------------------|--------|------------------|| BB | 1787 | 0.29 | B | 0.54 || Bb | 3039 | 0.50 | b | 0.46 || bb | 1303 | 0.21 | Total | 1.0 |
Hardy-Weinberg Principle
- Predicts allelic and genotypic frequencies.
- Provides theoretical baseline for actual changes observed in populations.
- Deviations from predictions indicate evolution and unknown factors influencing changes.
Equations:
- Allele Frequency: p + q = 1
- Genotype Frequency: p² + 2pq + q² = 1

Assumptions:
1. Large population to overcome random events.
2. No mutations.
3. Random mating (no sexual selection).
4. No gene flow (no migration).
5. No natural selection (no selection pressure).
Implications of Violation:
- Any violation can cause drastic changes in allele frequencies over generations.
Lab Procedures:
- Simulate allelic and genotypic frequency changes under different scenarios.
- Use colored beads to represent alleles (e.g., blue for B, red for b).

Table 1 - Genotypic & Allelic Frequencies:
- Track frequencies for parental and offspring populations.
Questions:
1. Match of allelic frequencies between generations.
2. Possible violated assumptions if differences noted.

Selection:
- Differential reproduction of phenotypes based on environmental pressures.
Negative Selection:
- Non-adaptive traits decrease in frequency due to reduced survival.
Procedure Steps:

Graphing:
- Create line graphs to visualize genotype frequency changes across generations.

Table 2 - Genotypic Frequencies:
- Record results for successive generations.
Questions:
1. Calculate fifth generation allelic frequencies.
2. Analyze frequency decrease in bb individuals.

Definition:
Migration of individuals results in gene flow between populations.
Simulations to examine variability in allelic frequencies based on initial differences and migration rates.

Table 3:
- Recording allelic frequencies before and after migration for both populations.
Procedure steps include repeating exchanges across generations.

Definition:
- Change in allele frequency due to random sampling.
Effects:
- Impact greater in smaller populations.
- Types of genetic drift:
  - Bottleneck effect
  - Founder effect
Procedure Steps: