Evolution I Scott Bowling Topher Gee Stan Schneider

Evolution I Scott Bowling Topher Gee Stan Schneider Beth Schussler Randy Small Min Zhong Facilitator: Paula Lemons

Evolution I • Topic: Evidence for and mechanisms of evolution • Introductory Biology (majors), Large enrollment (200+/section) • We are assuming students “know”: – Definition of evolution – Hardy-Weinberg Equilibrium and problem solving – Evolutionary processes

Tidbit Learning Goal • Students will demonstrate an understanding of evolutionary processes

Tidbit Learning Objectives • recall Hardy-Weinberg and evolutionary processes Given a scenario, students will: • identify whether evolution has occurred and articulate the evidence • predict the mechanism(s) driving evolutionary change and identify the necessary evidence

• Pea plants have two flower colors: purple and white • Trait controlled by one gene: purple dominant to white

Frequency of white flower allele (q) 1 0, 9 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 0, 1 0 0 1 2 3 4 5 6 7 8 9 10 11 Generation On your own, summarize what this figure is telling you.

Frequency of white flower allele (q) 1 0, 9 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 0, 1 0 0 1 2 3 4 5 6 7 8 9 10 11 Generation In small groups, share your ideas.

Frequency of white flower allele (q) 1 0, 9 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 0, 1 0 A B C Graph here 0 1 2 3 4 5 6 7 8 9 10 11 Generation Look at the shaded Regions (A, B, and C). Over which, if any of these regions has evolution occurred for the flower color gene? 1. A only 2. B only 3. C only 4. Both A and B 5. Both A and C 6. Both B and C 7. All three regions 8. None of these regions

Frequency of white flower allele (q) 1 0, 9 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 0, 1 0 A B C 0 1 2 3 4 5 6 7 8 9 10 11 Generation Discuss the importance of the following factors in deciding whether evolution has occurred: • Allele frequencies • Number of generations • Magnitude of change

Frequency of white flower allele (q) 1 0, 9 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 0, 1 0 A B C Graph here 0 1 2 3 4 5 6 7 8 9 10 11 Generation Look at the shaded Regions (A, B, and C). Over which, if any of these regions has evolution occurred for the flower color gene? 1. A only 2. B only 3. C only 4. Both A and B 5. Both A and C 6. Both B and C 7. All three regions 8. None of these regions

Each group will be assigned one evolutionary process to discuss and explain to the rest of the class: 1. 2. 3. 4. 5. Genetic drift Mutation Non-random mating Migration (gene flow) Natural selection

• Dr. Sally Slither conducted a study on two populations of lizards: one on an isolated island the other on the mainland. – Generation time = 2 years – Island population (N = 1, 000) Googly-eyed – Mainland population (N = 100, 000) • In each population, some have googly-eyes (dominant) and some have small eyes (recessive). Small-eyed

Dr. Slither’s 20 -yr study of eye size in lizard populations

Dr. Slither’s 20 -yr study of eye size in lizard populations Graph here Based on the figure above, what is the most likely explanation for why the island population’s allele frequency is more erratic than the mainland’s? 1. 2. 3. 4. 5. Genetic drift Mutation Non-random mating Migration (gene flow) Natural selection

• Googly-eyed lizards are more sensitive to light and prefer dimmer conditions. • The mainland habitat is being deforested by human activity.

Dr. Slither’s 20 -yr study of eye size in lizard populations Given what you know, what could explain the mainland population’s gradual shift in allele frequency over time? Genetic drift Mutation Non-random mating Migration (gene flow) Natural selection

Homework • For either lizard population (mainland or island), what evidence would you need to support the hypothesis that EACH of the following is occurring: – Natural selection – Non-random mating – Migration

Summative Assessment A population of spiders includes individuals with plain legs (recessive) as well as individuals with yellow bands on their legs (dominant). You have a data set that spans multiple generations for this population. In the first generation your data indicate that of 100 spiders, 64 had yellow bands on their legs. Five generations later, the population had grown to 10, 000 spiders and included 1, 600 with plain legs. 1. Has evolution occurred over these generations? Explain your reasoning and show supporting work. 2. Has natural selection occurred on the yellow band phenotype? Why or why not? 3. What data set(s) would you need to collect to identify the mechanism of evolution?

Learning Objective Assessment Active learning Low Order/ High Order Recall Hardy. Weinberg principles and evolutionary processes Formative: Explain HW principles Group discussion Low Order Identify whether evolution has occurred & the evidence Formative: Evaluating population data to identify when evolution has occurred; pinpointing the evidence Clicker questions – discussion – repoll High order Predict the mechanism(s) driving evolutionary change and identify the necessary evidence Formative: Evaluating population data in scenario to identify potential evolutionary mechanisms. Clicker questions – discussion – repoll (multiple sections of a scenario) High order Formative: Homework assignment. Summative: Exam question to test student ability to identify whether or not evolution has occurred, and what mechanisms might have resulted in that evolution. Diversity Female scientist named in scenario. Group members presenters are diverse. Read clicker questions & group discussion questions to students to accommodate learning style diversity & students with Diversity: disabilities. Active learning includes both group and individual activities.

OPTIONAL? What evidence is necessary to know whether evolution has occurred within a population? • Individually, write a one-minute essay • Brief group discussion

Island population (1000 total) Generation 1 10 Googly-eye 360 640 Small-eye 640 360 Generation 1 10 Googly-eye 75, 000 70, 000 Small-eye 25, 000 30, 000 Mainland population (100, 000 total)

• The island habitat is undisturbed and heavily forested.