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Questions? 15.3: Evidence For Evolution Support for Darwin’s ________________of natural selection. A _________________ is a hypothesis supported by a large amount of scientific _________________ from many different observations and experiments. I. Comparative Anatomy ______________________________________ is the study of the body structures (anatomy) of animals of different species. A. Homologous structures have _________________________mature forms but develop from the ______________ embryological tissue. (from the Greek "homos" meaning "same") In other words, if organisms have homologous structures they share a _____________________________________. The more _____________________ the homologous structure, the more _________________________they shared a common ancestor. The "mature" appearances are different for adaptations to different environments Zoo of you interactive Head + Body: http://www.pbs.org/wgbh/nova/evolution/zoo-you.html B. Vestigial Organs ______________________________ are body structures that no longer serve the original purpose, but was probably useful to an ancestor Examples: human appendix, dewclaw in dogs and a whales pelvic bone: II. Fossils ________________________ form when an organism becomes buried in mud, volcanic ash, or sediments Fossils from old rock layers were compared with fossils from new rock layers Provides a record of early life and evolutionary history. Record is incomplete. There are "gaps." __________________________ or "intermediates" can fill the gaps, providing a continuous picture of evolution. Bones can be _____________________structures, as in whale evolution. Fossil record shows how life on Earth has changed over time III. Embryology An ______________is the earliest stage of growth and development Similarities in embryos suggest a _____________________________. Embryological tissues with common cells and growth patterns develop into __________________________________. This is especially true of organisms with backbones. Guess the embryo: IV. V. Biochemical = Amino Acids and DNA The more similar the _______and ________________sequences are, the more closely related organisms are. Scientists can determine when species __________________from one another in evolutionary history through the study of DNA and amino acid comparisons. Of course, Darwin did not use this evidence in his theory! It added support for the theory later. The more biochemistry two species share, the more ________________ they diverged. (The more _______________________________ they are). Analogous Structures However, animals living under ______________ ecological conditions on different continents evolve features in common. These features in common are called ____________________ that are different in basic structure or form but the same in function. _______________ indicate a __________________________ (unlike all the other “evidence” we discussed today). __________________ provide evidence of evolution by ______________________________in response to environment. Example: butterfly’s wing, bat’s wing, bird’s wing and pterosaur’s wing Summary____________________________________________________________________ ______________________________________________________________________________ _____________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________