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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.

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Presentation on theme: "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."— Presentation transcript:

1 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

2 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.

3 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

4 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…

5 Takin’ a dip in the gene pool! AKA…Changes in Allele frequencies and the effects on a population simulation!

6 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?

7 Part A demo After you are done check out the board for new instructions

8 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.

9 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.

10 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 2 nd 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.

11 Allele Frequencies review I.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…

12 The Hardy-Weinberg Equilibrium 1.Be Large 2.Be Isolated 3.Randomly Mate 4.Have all individuals have an equal chance of survival 5.Have no mutations Godfrey Hardy (1877-1947) English Mathematician Wilhelm Weinberg (1862-1937) German Physician http://anthro.palomar.edu/synthetic/synth_2.htm

13 Is this realistically possible? Discuss at your table if it is and why it is or isn’t.

14 Part B & C In both of these which conditions were not met? 1.Be Large: not met 2.Be Isolated: not met, death of aa & possible death of AA in part C 3.Randomly Mate: yes met 4.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

15 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!

16 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=1fN7rOwDy MQhttp://www.youtube.com/watch?v=1fN7rOwDy MQ 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.

17 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.

18 What Causes Evolution? 1. Mainly Natural Selection Even slight advantages cause a change in the gene pool

19 Side bar: Small pop vs. large pop

20

21 2. Migration aka Gene Flow An individual can bring genes from one population to another, which changes the population

22 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.

23 Sample of Original Population Founding Population A Founding Population B Descendants Ex A: Founders Effect Founding Population B

24 Ex B: Bottleneck effect: a small population is left behind after a disaster/disturbance and has different relative frequencies than original population.

25 4. Mutations Errors when DNA is copied lead to new genes They change the gene pool or the collection of all the genes

26 5. Sexual Selection Traits that help individuals find a mate can become common – even if they decrease the chances of survival http://www.youtube.com/watch?v=gKybAp-- n7Mhttp://www.youtube.com/watch?v=gKybAp-- n7M 4:00 peafowl http://www.youtube.com/watch?v=7dx2CUMt Z-0http://www.youtube.com/watch?v=7dx2CUMt Z-0 1:00 dancing bird

27 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

28 HW: Microevolution worksheet Due…Monday for 2 nd period. I will not be here but you will put it in the bin for full credit. You have been warned! Due Tuesday for 5 th & 7 th period.


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