NOTES: GENETIC DRIFT Objective: What is genetic drift and how does it affect the diversity of a population?

Title Box 1: What is genetic drift?

Changes in a small population’s allele frequency due to random chance

Not based on fitness its about luck

Title Box 2: What causes genetic drift?

Natural disasters: hurricanes, volcano, tsunami, earthquakes, fire, etc.

Random Events: stepped on, ran over, picked up, etc.

Title Box 3: What are the types of genetic drift?

Founder’s effect: part of the population immigrates to and colonizes a new area

Bottleneck effect: a disaster happens leaving few survivors from an original population

Talk it Over and Write it Down: Look at the population of cats before and after. 1)What do you notice happen to the

phenotypes?2)What happened to genetic diversity? 3)What type of genetic drift

happened?

Title Box 4: Quick Write

DIE in flood

Title Box 5: What does genetic drift do to a population?Decreases diversity within a population

Affects small populations

Genetic Drift WS1. Roll dice put

dot next to that # worm

2. Example roll 3 put dot next to worm 3

3. Roll 5 more times (total 6 times)

4. Color the next generation worms those colors with dots

5. Repeat until you get to generation 4

Title Box 6: Exit Ticket

At the bottom of today’s notes answer the following questions in complete sentences:

Explain how genetic drift affects the diversity of a population. How does this affect the fitness of the population?

What is genetic equilibrium?

When allele frequencies remain the same

No change means no evolution

What are the conditions for genetic equilibrium?

1. Random mating 2. Large population 3. No immigration/

emigration 4. No mutations 5. No natural

selection