1. Natural Selection occurs even today - ex: pesticides, some insects have traits that protect them from pesticides. They survive and pass on their traits, those insects survive Forms of Evidence - since Darwin’s time, scientists have found evidence that supports the theory of evolution

2. -* Similar body structures, patterns of early development, molecular structure, and fossils all provide evidence that organisms have changed over time Similarities in Body Structure - Comparative Anatomy - comparison of structures of different organisms - organism’s anatomy is its body structure - fishes, amphibians, reptiles, birds, and mammals have similar anatomy (internal backbone skeleton). All classified as amphibians

3. - front limb bones of dolphins, birds, & dogs arranged in similar way, providing evidence that they evolved from common ancestor Homologous Structures - similar structures that related species have inherited from a common ancestor Similarities in Early Development - during early development, all vertebrates have a tail and rows of tiny slits in throat, suggesting that they share a common ancestor

4. Similarities in DNA & Proteins - structure of organism’s DNA & protein molecules provide evidence of evolution - if two species have similar DNA & proteins, they may have evolved from same ancestor How Do Fossils Form? - *Most fossils form when organisms that die become buried in sediments (soil & rock) - layers of sediments from rivers or ocean settle to bottom & cover dead organisms, over millions of years, layers harden to sedimentary rock

5. - Molds & Casts - Mold - a hollow area in sediment in the shape of an organism or part of an organism - forms when the hard part of the organism is buried in sediment - Cast - solid copy of the shape of an organism - from water carrying minerals & sediment that seep into empty space of a mold, opposite of its mold form

6. - Petrified Fossils - fossils where minerals replace all or part of an organism - ex: petrified wood, formed after sediment covered the wood, water with dissolved minerals soaked into plant cell spaces, over time, the minerals hardened & preserved the wood - Trace Fossils - type of fossil that provides evidence of the activities of ancient organisms - ex: fossilized footprint, allows scientists to determine animal’s size & behavior (walk on 2 or 4 legs, alone or in groups), a trail or burrow

7. - Preserved Remains - some processes preserve organism remains with little or no change - ex’s: - Brea tar pits; animals became stuck in the tar & died, tar soaked into the bones, preserving bones from decay - Amber (sap) insects get trapped on resin, then more sap builds up around & preserves - Freezing

8. What can be learned from fossils? - Paleontologists - scientists who study fossils - * the fossil record provides evidence about the history of life & past environments on Earth. In addition, scientists use fossils to study the rate at which evolution has occurred - History of life - oldest rock layers contain oldest fossils; simple organisms (bacteria) - younger rocks contain most recent & complex fossils (plants & birds)

9. - shows life on Earth has evolved over time with life beginning with one-celled organism, then plants & animals appeared - Past Environments - Paleontologists use fossils to build a picture of Earth’s past environments (desert, forest, freshwater swamp) - fossils show how environment has changed; presence of coal in Antarctica shows climate was warmer at one time, as coal is derived from remains of plants - fossils show how Earth’s surface has changed; fossils from 50 million years ago found in Wyoming, now a region of dry plains. But the fossils found were those from a region of shallow lakes & swamps, subtropical climate

10. - Gradualism - a hypothesis that evolution occurs slowly but steadily - scientists study fossils to try & determine the rate evolution occurs - if gradualism is correct, there should be records of intermediate forms between a fossil & its descendants. Long periods of no fossil changes, then suddenly different fossils. Possible incomplete fossil record, creating gaps

11. - Punctuated Equilibria (bursts) - hypothesis that species evolve during short periods of rapid change - periods of rapid change are separated by long periods of little or no change Most scientists today believe evolution can occur both gradually at times, and more rapidly other times