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Download Chapter 13 Notes Continued Evidence of Evolution
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Chapter 13 Notes Continued Evidence of Evolution There are five modern day evidences that support the work of Darwin • • • • • Age of the Earth Fossil evidence Anatomical evidence Biochemical evidence Embryological evidence 1. Age of the Earth • While many bible scholars estimated the earth to be 30,000-40,000 years old, Darwin predicted the Earth to be Millions of years old. (Deep Time) • Modern evidence suggests the earth to be 4.6 Billion years old 2. Fossils • Fossils are the remains or traces of remains of organisms that lived long ago • Typically are the bones, teeth or shells of past animals • Imprints and casts are other types of Fossils • Most fossils are formed in sedimentary rock Fossils • Age is important! Fossils can be “dated” by radioisotopes of Carbon-14, Uranium-238 or Potassium-40. • The half-life of these chemicals is the amount of time it takes for that chemical to decay by 50% • Half-life for Carbon-14 is 5,730 years Fossils • Age of the rock a fossil is found in, can also be tested. • Law of Superposition- fossils found deepest in the rock strata are older than the strata at the top. Is useful for following evolution progression • Study of Fossils is called Paleontology Law of Superposition 3. Biochemical Evidence • Chemicals such as Proteins, Amino Acids and Nucleic Acids (DNA and RNA) can be studied to compare organisms. • examples: chimpanzees and Humans are 96% the same by chemical composition • Horseshoe Crabs are more related to Arachinids than Crusteaceans. 4. Anatomical Evidence • Vestigial Organs or Structures- have no apparent use or function. • May be clues to a distant past • Examples: wings of flightless birds, pelvic bones in Whales and some Snakes Vestigial organs continued • Human Vestigial organs- Appendix, Wisdom and Canine teeth, Male nipples, Human Tailbone and Muscles to move ears • Homologous Structures- Body parts that differ in use but are similar in structure. • A Man’s arm and a Whale flipper would be considered Homologous. • Analogous Structures- Body parts that are different in structure but perform a similar task. • Ex. Bats wing, Butterfly’s wing and Birds wing are analogous 5. Embryological Evidence • In early embryos, Organisms that are related develop in a similar way. All vertebrates develop alike until late stages. • Under this concept, all vertebrates are more closely related to Echinoderms (starfish) than other invertebrates • See next slide.
