NATS 1840 Lecture Notes - Tiktaalik, Reproductive Isolation, Macroevolution
19 Nov 2012
School
Department
Course
Professor
Document Summary
Science, technology and the environment (sc nats 1840a) . Readings: chapter 5. 4, 12, 13 speciation, evidence and extinction. Natural variation determined at molecular level (alleles of genes) Prevalence, or frequency, of alleles in a population determined by environmental conditions. New species result from long-term evolutionary divergence of populations. Might result from migrations, or other causes of physical/environmental isolation. Physical isolation, followed by long periods of microevolution, leads to reproductive isolation. Evolution common misconceptions clarified: populations evolve. Individuals do not: fittest does not refer to physical strength. The fittest individuals are those able to leave the most descendants: there is no plan . Genetic mutations underlying evolution appear to be completely random. Structural features common to many species of plants or animals, suggesting a common lineage. Chronological arrangement reveals changes in structure and complexity. Comparison with today"s organisms shows progression of common features. Limited by rarity of fossils there are gaps in the record.
