need title. evolution tree thinking summer institute 2014 ucr, riverside sofia, blaire, jinghua,...

Need title

EVOLUTIONTree Thinking

Summer Institute 2014 UCR, Riverside

Sofia, Blaire, Jinghua, Kelsey, Lauren, Brad, Beth, Kris“Education Evolves”

Audience: Introductory Biology

• Prerequisite topics:– Scientific Method– Natural Selection – Descent with modification

Learning Goal

• Students Should be Able to Use Phylogenetic

Trees to Understand Evolution

• Today’s Teachable Tidbit: Tree Thinking

Learning OutcomesStudents should be able to:

• Apply the descriptive terminology associated with phylogenetic trees• Use shared derived characters to build phylogenetic trees • Understand difference between homology and convergence• Identify common ancestors• Interpret a given phylogenetic tree • Use the tree to make an evolutionary inference

Non-content learning outcomes:• Communicate science• Collaborate effectively• Think creatively

Previous lesson: Anatomy of a Tree 1. Think-Pair-Share or homework assignment:Add the following terms to the blank tree:– Branch (Label only)– Node (Label and count)– Tip (Label and count)– Clade (Label and count)

Character Mapping

Character Mapping

In pairs:1. On your handout, write down each

morphological character on the tree at least once.

Report Out

Evolution of Morphology

Evolution of MorphologyIn groups for your assigned clade:• Identify the location on the phylogeny of the

most recent common ancestor• Then, from your stack of characters…– Find those that define your clade

• Of the remaining characters…– Find those that are features of the common ancestor

Class Consensus: Complete Summary chart

Group Work Summary

• Shared Derived = characters that define your clade

• Shared Ancestral = other characters they share

photos

Put it all Together

• Convergence: a character that evolved independently multiple times in different branches

• Why do you think convergence is evidence for evolution by natural selection?

• Discussion and report back.

Final Reflection

• One minute writing assignment: Can you think of other groups not shown here that also evolved wings for flight? How do you know that this is due to convergent evolution?

• Write your name on it. • Turn it in on your way out.