Transcript 22evol
Chap 22 Evolution Cuvier tried to explain the fossil record by using the idea of Catastrophism. Cuvier – Catastrophism HuttonGradualism Lyell- Catastrophies explain the different layers of fossils Geological processes take thousands of years processes work the same now as in the past Uniformitarianism- geologic 1. Earth is very old 2. Slow change can result in substantial change over time Evolutionary Theory Theory of Use and Disuse Theory of Acquired Characteristics 5 Parts to Darwin’s Theory of Evolution • There is always variation in the population • There is always a struggle for existence • Some characteristics allow for some individuals to survive and reproduce better than others • These characteristics are heritable • It takes many generations for change to occur Thomas Malthus Populations Geometric Inc Logrithmic Exponential Food Supply Arithmetic 8. Vestigial Organs Degenerated organs that have lost all or most of its original function 9. Adaptive Radiation Rapid adaptation of one ancestral organism to a wide range of environments leads to the formation of many new species (Transitional Species: fossils show change over time) Homologous Structures: Comparable structures that have taken on different functions as a result of modification from a common ancestors (Artificial Selection of domestic species) Changes in environment can affect survival and change overall the population’s characteristics. Transitional Species Descent with modification Descent with modification Homologous Structures Vestigial Organ Biogeography is the science which deals with geographic patterns of species distribution and the processes that result in such patterns Present Darwin expected the plants on the Galapagos to resemble those found in Europe, why was this not so? Adaptive Radiation in Hawaiian Honeycreepers Lines of Evidence for Evolution • • • • • • • Domesticated Species/ Artificial Selection Transitional Species/ Fossil record Homologous structures Vestigial structures Embryological Structures Biogeographical evidence Biochemical evidence - DNA, Protein, Amino Acid Sequencing • Adaptive radiation Unrelated organisms adapt to similar environmental conditions