1. Evolution- an empirical way of knowing
Student

2. The nature of science Evolution is part of science
Science is an empirical way of knowing about the process directing life in the natural (physical) world
Empirical means derived from observation or experience
Evolution takes observations and experiments and fills in the gaps to trace all life to a common ancestor

3. Trunk or tangle?
All of the equipment we had before and ways of testing weren’t as good as they are now. Even by the 1950’s we couldn’t test that much about genetics. We had to guess by looking at skeletons and fragments of bones. Scientists pieced that together, and predicted we had a common ancestor, and the ancestor evolved into humans like an oak tree

4. Trunk or tangle?
In the last several decades, we have gotten to study the DNA. DNA tells us what type of life we will make, like a cookbook tells us what type of meal we’ll make if we follow the recipe. We used to think we shared a common ancestor, and different kingdoms of life branched off a main trunk. Now that we’ve studied much more DNA, we predict that near the beginning, we didn’t have one ancestor, but many that were all tangled around each other like roots in a swamp tree.

5. Trunk or tangle? *Sketch of “mangrove”-like evolution
Visual of “mangrove” oak tree
*Woese, C. On the evolution of cells. PNAS. (2002), 99 (13), pg. 8743