Transcript Chapter 22
Chapter 22 Descent with Modification: A Darwinian View of Life • Think quietly for a minute…how would YOU define evolution? • What was Darwin’s definition of evolution? • Did he actually use the term evolution in his book? Classification of Species • Aristotle (384-322 B.C.) – Scala Naturae • Carolus Linnaeus- binomial system of naming – What was the main thing that was determining ideas about how species formed up until the 19th century? • Lamarck – first hypothesis on HOW things change…what did he believe? Paleontology Contributions • Georges Cuvier (1769-1832) – Developed paleontology – Older strata = more dissimilar – Completely against evolution so how did he explain the large changes and differences? – Catastrophism • James Hutton (1726-1797) – gradualism • Charles Lyell (1797-1875) - uniformitarianism Darwin’s Background • 1809-1882 • Cambridge then HMS Beagle • Beagle Discoveries/Voyage: – Species resembled nearby species rather than species in similar climates elsewhere – Earth is older than previously thought – Galapagos species found nowhere else on earth The Origin of Species • Adaptations - something that allows an organism to survive better in its environment – Examples? • Adaptation = better survival = more offspring = trait passed on – Natural selection – Described to Lyell…Alfred Russel Wallace publishes similar ideas first Natural Selection • Artificial vs. Natural Selection five • 4 principles – – – – Variation Adaptation Overproduction Descent with modification • Key points: – Individual evolution – Heritable traits – Environmental context digit s wrist bone Supporting Evidence • Direct Observation • Fossil Record – Actual fossils – Age of fossils • Homology – – – – Homologous structures Vestigial structures Molecular homologies Convergent evolution • Biogeography