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3/6 Daily Catalyst Pg. 30 Hardy-Weinberg Equilibrium

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Presentation on theme: "3/6 Daily Catalyst Pg. 30 Hardy-Weinberg Equilibrium"— Presentation transcript:

1 3/6 Daily Catalyst Pg. 30 Hardy-Weinberg Equilibrium
1. Why can’t an individual evolve? 2. What causes gene pools to change? 3. What is effected more by changes in gene frequencies, large or small populations?

2 3/6 Birthday fun!

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4 3/6 Class Business Pg. 30 Hardy-Weinberg Equilibrium
Quiz #7 Evolution Evidence TODAY! I will be gone Monday You will have a sub packet due Tuesday Ecology paper due Friday, March 6th Library work time on Tuesday Works cited page Visual aid ed to

5 3/6 Agenda Pg. 30 Hardy-Weinberg Equilibrium
Daily Catalyst Class Business Objective Hardy Weinberg notes Quiz #7 Evolution Evidence Timed 10 passage Trade and grade

6 3/6 Objective Pg. 30 Hardy-Weinberg Equilibrium
We will be able to use data from Hardy-Weinberg equilibrium to analyze the effects of natural selection on a population.

7 Darwin’s Theory of Evolution
With a partner, review: Darwin’s Theory of Evolution Natural Selection DNA similarities as evidence Gene pools Give students, 3 minutes to review the following topics with a partner.

8 Stop and Jot What is a better source of genetic variation, sexual or asexual reproduction? Sexual reproduction is a better source of genetic variation because there is a recombination of alleles allowing new gene combinations and new traits to arise. What is the advantage of both types of reproduction?

9 Key Point #1: Causes of Evolution
1. Disturbances (environment) 2. Migration/immigration 3. Mutations 4. Natural Selection 5. Sexual Reproduction Change in genes over time These are factors that can cause a gene pool to change which allows evolution to occur.

10 When is the gene pool not changing?
The gene pool is always changing! We can’t just STOP evolution from occurring.

11 This is called HARDY-WEINBERG EQUILIBRIUM.
Key Point #2: When there is no change in gene frequency, the population is said to be stable and non-evolving. This is called HARDY-WEINBERG EQUILIBRIUM. (Named after two scientists describing a stable population)

12 In your opinion thus far, is Hardy-Weinberg Equilibrium highly likely?
Turn and Talk In your opinion thus far, is Hardy-Weinberg Equilibrium highly likely? Why or why not? Turn and talk then share out

13 Hardy-Weinberg Equilibrium
Key Point #3: FIVE Conditions of HWE: Large population No gene flow No mutations Random mating No natural selection Leave space to add notes under each conditions Godfrey Hardy ( ), an English mathematician, and Wilhelm Weinberg ( ), a German physician, both found a way to link genetic probability and evolution the early 20th century. Hardy and Weinberg independently worked on finding a mathematical equation to explain the link between genetic equilibrium and evolution in a population of species.

14 Hardy-Weinberg Equilibrium
1: Large population so that the loss or gain of genes does not change the gene pool . 2: Populations must be isolated. No immigration (out) or emigration (in). 3: Mutations always occur! This slide and the next slide explain that three of the five conditions for Hardy-Weinberg can never be met, therefore evolution occurs within populations.

15 Hardy-Weinberg Equilibrium
4: Mating is never random. i.e.: Pollen from an apple tree in Ohio is more likely to pollinate a tree in Ohio than one in Washington state. 5: Every offspring has an equal chance of survival. There is always variation. Can all of these conditions be met?? NOPE! Since 3 out of the 5 HWE conditions can never be met, evolution DOES occur and allele frequencies do indeed change. In other words, HWE is very rare! Please know the conditions that can never occur.

16 Hardy-Weinberg Equilibrium
Large population No gene flow No mutations* Random mating* No natural selection* Godfrey Hardy ( ), an English mathematician, and Wilhelm Weinberg ( ), a German physician, both found a way to link genetic probability and evolution the early 20th century. Hardy and Weinberg independently worked on finding a mathematical equation to explain the link between genetic equilibrium and evolution in a population of species.

17 How do we calculate the equilibrium?
Key Point #4: Allele Frequency: Alleles- a version of a trait Blue eyes, blonde hair, attached earlobes p + q = 1 Key Point #5: Genotype frequency: Genotype- genetic make up p^2 + 2pq + q^2 = 1 If HWE does occur, how do we calculate it?

18 Let’s break down the equations
p presents the dominate trait Capital letters q represents the recessive trait Lower case letters pq represents the… Heterozygous/Hybrid trait!

19 Example #1 The allele frequency for the dominant trait is .8. Determine the allele frequency of the recessive allele. What equation will we use? p + q = 1 What do we know? Dominant trait (p) is .8 What do we want to know? Recessive trait (q) is ??? .8 + q = 1 q= .2 (20% of the population have the recessive allele)

20 Example #2 The allele frequency for the recessive trait is .3. Determine the allele frequency of the dominant allele. What equation will we use? p + q = 1 What do we know? Recessive trait (q) is .3 What do we want to know? Dominant trait (p) is ??? p + .3 = 1 q= .7 (70% of the population have the recessive allele)

21 Example #3 Determine the percent of the population that is hybrid if the allelic frequency of the recessive trait is .2 and the allelic frequency of the dominant trait is .8. What equation will we use? What do we know? What do we want to know?

22 Timed 10 Directions: Silently and independently complete the timed 10 passage. When you finish your timed 10, give Mrs. Ireland your passage and pick up quiz #7 and being your quiz. Time: 10 minutes Noise: 0 (SILENT)

23 Quiz #7 Directions: Silently and independently complete the quiz. Turn your quiz into the basket when you are finished. Time: 12 minutes Noise: 0 (SILENT)


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