1. Evolution Lesson 1: An Introduction to Charles Darwin and the Nature of Science

2. “A scientist, however, gifted, can be compared with a fly crawling on the inside wall of a cathedral; if it could draw what it sees, the fly’s picture of the cathedral would be as crude as early maps of the world; if it could voice its speculations about the size, appearance, and purpose of the cathedral, the fly’s opinions would be received even more guardedly.” -- Frederick Aicken, The Nature of Science, pp.29-30

3. Evolution As An Idea Evolution As An Idea “ If I were to give an award for the single best idea anyone has ever had, I’d give it to Darwin, ahead of Newton and Einstein and everyone else. In a single stroke, the idea of evolution by natural selection unifies the realm of life, meaning and purpose with the realm of space and time, cause and effect, mechanism, and physical law. But it is not just a wonderful idea. It is a dangerous idea.” Daniel Dennet

4. Evolution as an Idea “Evolution is one of the most powerful ideas ever to emerge from science. It is the very foundation of biology and the key to understanding our own human origins. The mechanism of evolution helps determine who lives, who dies, and who gets the opportunity to pass on traits to the next generation. At the same time, evolution ranks as one of the most widely misunderstood scientific principles in America today.” Richard Hutton, Executive Producer, Evolution WGBH Jody Patton, Executive in Charge, Clear Blue Sky productions

5. Darwin’s Voyage of Discovery

6. Galapagos Islands

8. Figure 22.6 Galápagos finches

22. Darwin and the Galapagos Consider the following: 1.How did the Galapagos Islands get there? 2.How did the first plants get there? 3.How did the first animals get there? 4.What is ecological succession?

26. Ecological Succession process in which communities of plants and animal species in a particular area are replaced over time by a series of different and often more complex communities. Two stages – Primary succession – Secondary succession

27. Primary Succession succession in a bare area (no mature soil) that has never been occupied before

28. Secondary Succession succession in an area in which natural vegetation has been removed or destroyed but the soil remains

29. Ecological Succession

31. Darwin’s Theory of Natural Selection 1.Variations exist 2.These variations are heritable 3.Some variations are advantageous and some are disadvantageous 4.Organisms compete for limited resources 5.Organisms with advantageous variations survive and reproduce most successfully, leafing more organisms like them in the next generation 6.Over time, the population changes to become more like the organisms with advantageous variations 7.Today’s species have descended from past species 8.All organisms are related and are members of a single tree of life

32. Examples of Natural Selection English Peppered Moth

33. Darwin's Finches

34. Darwin’s Theory of Natural Selection Individual organisms differ; variation is heritable Organisms produce more offspring than can survive; they compete for limited resources Some variations are advantageous; individuals best suited to their environment survive and reproduce successfully Species alive today descended with modification from ancestral species that lived in the past

35. Darwin’s Tree of Life

36. Evolutionary Classification Using Cladograms Cladogram – diagram used to show the evolutionary relationship between organisms Cladograms are constructed using derived characteristics – Derived characteristics - characteristics that appear in recent parts of the lineage but not in older members; new characteristics that evolve over time – Each branch or junction shows the appearance of a new trait – Cladograms demonstrate when characteristics first appeared

37. Cladogram of vertebrates http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif

38. http://biology.unm.edu/ccouncil/Biology_203/Summaries/Phylogeny.htm