5/2-5/5• 1- check in HW- natural selection – please review your answers with your table mates– Questions on the HW?

• 2- presentations: evidence for evolution– Take notes and ask questions!

• 3- crash course• Please do a murkie today!• HW- Quiz: History, natural selection, evidence

• Presentations• Make sure you are taking notes!• If you feel like you don’t understand…ask

questions.• This information is in he book if you want more

information.• Email me if you have a question.• Finally, there is an optional worksheet on-line

about evidence for evolution.

5/6-5/7

• Please have your ID on• Who will be absent Friday?• Quiz- please put in the bin when you are

done.• Genetics and evolution• HW: TBD at the end of class

DNA and Variation in a POPULATION

• Recall: GENES are segments of DNA that code for a protein which then becomes a trait.

• Since variation is the result of different alleles, we can measure change in variations by measuring changes in allele frequency BECAUSE changes in the frequency of genotypes = changes in phenotypes.

• To demonstrate how frequencies change based on phenotype and the environment we will run a class simulation…

Takin’ a dip in the gene pool!

• AKA…Changes in Allele frequencies and the effects on a population simulation!

• 1. Read through Vocabulary• 2. Complete the allele frequency section (4 a & b)• 3. When done, answer the following on your own

on a separate piece of paper that you will attach to your packet.

• Label the question Part A- #5 & #6• Q: If both alleles are benign (have no positive or

negative effect on the fitness of the organism) what would you expect to happen to the frequency of these alleles over many generations. Make a claim and give your evidence/explain your position.

• Q: How many students are in class today?

• Part A demo• After you are done check out the board for

new instructions

• Once you have filled out the class data chart:• Fold your provided graph paper into quadrants (you

will be creating 3 different graphs)• Decide how you will graph the allele frequencies over 5

generations.• Set up your graph using all of the graphing rules. – Note: your ID makes a great straight edge– Please use the graph space appropriately (don’t make tiny

graphs/giant graphs)

• After you complete the graph answer the questions. Please use claim/evidence format to answer thoroughly. You may discuss the questions/answers with your table mate.

HW due 5/8(A)-9(B)• Complete Part A– Allele freq– After you complete the graph answer the questions.

Please use claim/evidence format to answer thoroughly. You may discuss the questions/answers with your table mate.

– Graph– Questions

• IF YOU ARE ABSENT DUE TO AP TESTING. You must go on-line for the data that will be collected & complete any homework for the next class or it will be considered late.

5/8-9• Presentations• Have Frequency Allele packet on desk for me to check

in. Discuss answers while I check in AND read directions for B and Predict

• Part B completed in class. • Part C completed in class.• HW: Microevolution worksheet• 2nd period! Remember that I am at a conference on

Monday. You will be running your class. #1 thing to remember is that you will be working on the computers and that your instructions will be on the HW website as a power point.

Allele Frequencies reviewI. Part A of our allele frequency simulation

shows a population that is not evolving. This is called equilibrium.

A. This means that allele frequencies for traits are not changing (in a statistically from one generation to the next in a population.

1. For this (no change in allele frequencies) to occur in a population, 5 conditions must be met. Called…

The Hardy-Weinberg Equilibrium1.Be Large2.Be Isolated3.Randomly Mate4.Have all individuals have an equal chance of survival5.Have no mutations

Godfrey Hardy(1877-1947)

English Mathematician

Wilhelm Weinberg(1862-1937)

German Physician

http://anthro.palomar.edu/synthetic/synth_2.htm

Is this realistically possible?

• Discuss at your table if it is and why it is or isn’t.

Part B & C• In both of these which conditions were not met?1.Be Large: not met2.Be Isolated: not met, death of aa & possible

death of AA in part C3.Randomly Mate: yes met4.Have all individuals have an equal chance of

survival: not met, Aa has the advantage (esp in part C)

5.Have no mutations: yes met, no new mutations

B & C are more typical of actual populations

• It is impossible, due to mutations, to have a real population that is in HW equilibrium.

• This equilibrium has an equation which allows scientists to quantify evolution!

Part C- Analysis

• 3b- The role of the environment is critical. In high malaria area sickle cell is actually a favorable heterozygous trait.

http://www.youtube.com/watch?v=1fN7rOwDyMQ 4:50

• 4c- different traits are favorable in different environments, the environment is a driving force in the selection of the phenotype that increases fitness thus indirectly selecting genotypes and the allele frequency.

Purpose of our activity is to introduce Two Ways to Look At Evolution

Microevolution• Changes in a gene

pool of a population

• E.g. a population accumulating longer neck genes, darker fur genes

Macroevolution• The formation of

new species or taxonomic groups

• How did animals evolve, how did mammals evolve etc.

What Causes Evolution?

• 1. Mainly Natural Selection• Even slight

advantages cause a change in the gene pool

Side bar: Small pop vs. large pop

2. Migration aka Gene Flow• An individual can bring genes from

one population to another, which changes the population

3. Random Chance (Genetic Drift)• In small populations, pure chance may cause

microevolution• Ex A: Founders effect: a small group of organisms

starts a new population, they many have different relative frequencies of alleles than the larger population they came from.

• If so, the population they start can be quite different from their original population.

Sample of Original

PopulationFounding

Population A

Founding Population B

Descendants

Ex A: Founders Effect

Founding Population B

Ex B: Bottleneck effect:• a small population is left behind after a

disaster/disturbance and has different relative frequencies than original population.

4. Mutations• Errors when DNA

is copied lead to new genes

• They change the gene pool or the collection of all the genes

5. Sexual Selection

• Traits that help individuals find a mate can become common – even if they decrease the chances of survivalhttp://www.youtube.com/watch?v=gKybAp--n

7M 4:00 peafowlhttp://www.youtube.com/watch?v=7dx2CUMtZ-0 1:00 dancing bird

Usually Female Choice• Females choose

which traits they like• These traits then

become more and more common over time

• Can lead to males looking very different than females

HW: Microevolution worksheet

• Due…Monday for 2nd period. I will not be here but you will put it in the bin for full credit. You have been warned!

• Due Tuesday for 5th & 7th period.