Bio 9D: Thursday, 4.28.11 Title: Evidence for Evolution

1. Bio 9D: Thursday, 4.28.11 Title: Evidence for Evolution • Homework: None • Silent Do Now: (in NB w/ title and date) As you know, different organisms are related to each other through evolutionary history – this means that they share a common ancestor. • What are some species that you think are close evolutionary relatives of humans? What are some more distant evolutionary relatives of humans? • What types of evidence could a scientist use to prove that certain species are close or distant relatives? • Today’s Objectives: • Explain the 3 types of homologies and use them as evidence to build evolutionary trees.

2. Evolution Dry Lab Part A Part A Computer Lab All in the Family: Which Animals are the Closest Relatives? Link: http://www.pbs.org/wgbh/evolution/change/family/index.html The purpose of this series of lab activities is for you to… • Examine and understand the evidence for evolution • Use that evidence to infer evolutionary relationships and build phylogenetic trees • Objectives for Class: • Use the three different types of homologies as evidence for evolutionary relationships

3. Bio 9D: Monday, 5.2.11 Title: Evidence for Evolution – Day 2 • Homework: Complete Evidence Lab Part A and the Ppt. Notes if you haven’t finished by the end of class. • Silent Do Now: (in NB w/ title and date) Go back to your class notes from 4/13/11 • What is the difference between micro-evolution and macro-evolution? Give an example of each. • Which is easier to understand and believe, micro or macro? Why? • Today’s Objectives: • Explain the 3 types of homologies and use them as evidence to build evolutionary trees.

4. Micro-Evolution • Small-scale • Changes in a population’s gene pool over time • Caused by natural selection and/or genetic drift Example: Average beak size in a population of birds increases over several generations. Micro-evolution leads to Macro-evolution • Objectives for Class: • Use actual evidence to explain how the four principles of natural selection shape the evolution of organisms

5. Macro-Evolution • Large-scale, often over a very long time • Branching of one species into two species • Leads to the idea that all species share a common ancestor Example:Evolution of whales from four-legged land mammals • Objectives for Class: • Use actual evidence to explain how the four principles of natural selection shape the evolution of organisms

6. EVIDENCE FOR EVOLUTION What is the evidence that all species on earth are related to each other and share common ancestors? Overview: 3 Major Types of Evidence: • Homologous Structures • Anatomical homologies and vestigial structures • Embryological/ Developmental • Molecular/Genetic • Fossils • Geographic Distribution of Species • Objectives for Class: • Describe the three different types of homologies and give examples of each

7. HOMOLOGOUS STRUCTURES – Similar structures due to sharing a common ancestor that had those structures • Objectives for Class: • Describe the three different types of homologies and give examples of each

8. Anatomical Homology – similar body parts or bone structures • Don’t necessarily have the same function now, but did in the common ancestor • Ex: human arm, cat leg, whale flipper, bat wing all have same bones • Objectives for Class: • Describe the three different types of homologies and give examples of each

9. Anatomical Homology, continued: Vestigial Traits - • Don’t have a function now, but suggest that they descended from an ancestor that did use them. • Examples: • human tailbone, human goose bumps, ostrich wingsEx: human tail bone, human goose www.toptenz.net • Objectives for Class: • Describe the three different types of homologies and give examples of each animal.nationalgeographic.com

10. Embryological/Developmental Homology Similar characteristics appearing during specific embryonic/ developmental stages of development • Examples: • fish, reptile, bird, and human embryos all have gill slits and a tail (but some lose these features before birth) • Objectives for Class: • Describe the three different types of homologies and give examples of each

11. Molecular/Genetic Homology • Similarities between DNA or amino acid sequences for different organisms • Closer the similarities = Closer relationships • Objectives for Class: • Describe the three different types of homologies and give examples of each

12. Don’t confuse Homologous Structures with Analogous Structures • Analogous Structures • structures that have the same function but NOT the same skeletal structure • This suggests these organisms did NOT descend from a common ancestor with that trait Ex: insect wing and bird wing Bird wing Insect wing • Objectives for Class: • Describe the three different types of homologies and give examples of each bio.miami.edu

13. Notes stop here. If you finish early: Go to http://tiktaalik.uchicago.edu/meetTik.html and explore the information about Tiktaalik. Click the green buttons to read more and get to interactive features. To earn extra credit for this, write a summary of at least 3 pieces of evidence that support the idea that the first 4-legged animals evolved from this fish.