1. AP Biology Day 9

2. Opener
Read the “Calculations and Creating a Histogram” section of your Modeling Natural Selection Handout. Answer these questions, in your notebook.
What is a histogram?
What can a histogram tell us about a population of organisms?

3. Homework Turn in Hardy Weinberg Practice
Finish for Homework, the Hardy Weinberg Packet
Assessments are graded, we will go over them on Friday. If you have a zero on one exam. Need to come see me before Friday

4. Plant Hairs
You need to count the number of trichomes on each plant and record down the number
How are we going to do that?
All the hairs?
Hairs on a certain part of the plant?
Keep careful record of what plant has what “hairyness”

5. Histogram Set up axes: Create a histogram—one bar for each range
X-ranges from data table
Y-number of plants in range
Create a histogram—one bar for each range
Helps predict how things will shift in a population: this is evolution!

6. Culling
We need to “weed” out the plants that don’t fit in the spectrum
Cut at the base carefully

7. Mating
Rated R

8. Agenda
Other causes of evolution
Hardy Weinberg Practice

9. LT #4
I can identify and describe processes that change the genetic structure of a population, resulting in evolution

10. Genetic Drift Fluctuations in allele frequencies in small populations
Result of random chance
No guaranteed adaptive benefit
Genetic drift affects the genetic makeup of the population but, unlike natural selection, through an entirely random process. So although genetic drift is a mechanism of evolution, it doesn’t work to produce adaptations.

11. Causes of Genetic Drift. . .
Bottleneck effect:
An event reduces the population size
Founder effect:
A new population is established by a small number of individuals
In both cases: the NEW gene pool can differ significantly from the old

12. Gene Flow
Adding genes or alleles to a population through the movement of individual organisms
No guaranteed adaptive benefit

13. Mutations Mutation Can effect phenotype No guaranteed adaptive benefit
Random changes in the nucleotide sequence of genes
Can effect phenotype
No guaranteed adaptive benefit

14. Non-random Mating Non-random mating No guaranteed adaptive benefit
Selecting mates
No guaranteed adaptive benefit

15. Natural Selection!
We already know about this

16. The Five Fingers of Evolution
Mutations
Non-random mating
Gene Flow
Natural Selection
Genetic
Drift

17. Hardy-Weinberg Practice
Get out the two packets from last class to work on