Chapter 15 Review & Wrap-up What is evolution? • Change in a population over time. Who was Charles Darwin? • He was a naturalist who noticed differences between organisms from the different Galapagos Islands. Came up with the theory of natural selection to explain how these small differences arose. A mechanism for change in a population. • Natural selection What are some important principles that result in natural selection? • Organism has to produce more offspring than can survive. • There has to be variation within the population • Beneficial variations are passed on to successive generations. • Over time, the beneficial variation makes up the majority of the population. An inherited characteristic which increases the chance of survival. • Adaptation What is mimicry? Give an example. • An adaptation that allows an organisms to look or behave like another. Ex: monarch and viceroy, snakes (coloration/rattling), yellow jacket and syphrid fly. What is camouflage? • Ability of an organism to blend in with its environment. What is an example of physiological adaptations (change in metabolic processes)? • Bacteria resistant to penicillin or insects resistant to DDT What is an example of indirect evidence that may support the theory of evolution? • Fossils, Homologous structures, Analogous structures, Vestigial structures, Embryology, Biochemistry Can an individual evolve? • Individuals cannot evolve…a population evolves. All of the different alleles in a given population. • Gene pool What is an allelic frequency? • Percentage of a given allele in a gene pool. What conditions are necessary in order for genetic equilibrium to be met? • -No mutations • -No genetic drift • -No gene flow Illustrate the results of stabilizing, directional, and disruptive selection. • Stabilizing • Directional • Disruptive What is speciation? • The idea that two members of the same species become so different that they are no longer able to interbreed producing fertile offspring. List two types of isolation that may result in speciation. • Reproductive and Geographic Describe two views of rates of speciation. • Gradualism (slowly over time) and Punctuated Equilibrium (short bursts of change and then no change) Differentiate between divergent and convergent evolution. • Divergent – one species becoming distinctly different • Convergent – Distantly related organisms deriving common traits.