April 27^th, 2007- Friday’s in the Lab: Bones, Homology and Phylogeny

• Start with Organizing/classifying organisms.
• Why did you organize them the way you did?
• See Paul Gobstein’s Organism Puzzle

• Run EvoBeacker Simulation. Discuss events. Then pose question…how do we know these relationships when no one was there to watch them…cannot be there because it takes too many lifetimes?

• Genealogies: who are you most closely related to? Brother/sister, then parents then…?

• Relationship btwn species: Vertebrates? Look at vertebrates and tell me which ones share a common ancestor most recently…or in other words, which two are the most closely related.
• Why? On what did you base your conclusion?
• Thus, similarity equals common ancestors. Why? b/c decent w/ modification…you inherit your dna from your parents
• Same with organisms. They look alike b/c they inherited dna from common ancestors, from parent species.
• Geneology vs Phlogeny trees

• So how do scientists represent evolutionary relationships?
• Vertebrate tree
• Human tree from Smithsonian Institute
• Populations diverging
  

• Homology versus Similarity due to Convergence
• Homology = similarity due to common ancestry
• Homology home
• Convergent Similarities
• Other examples: fins, wings, others?
• 3 criteria
• Devo Bio (haeckel)

• Students complete Homology Worksheet - bone activities

LUNCH

• Students finish Homology Worksheet - bone activities
• Demo Protein visualization:
• Procedure for using Visualizing Protein Structure: Go to Entrez Protein - search: “per2 NP_073728”.
• Protien Alignment & Questions
• Flowchart for Visualizing Protein Structure.
  

• Amino Acid Phylogenetic Worksheet and Fish Gel review
• Finish with web search of more fish info to first evolutionary fish tree.
• Making a tree from example protein gel data.