GEO 103 Lecture Notes - Lecture 13: Radiography, Gradualism, Meiosis
Document Summary
During voyage, darwin observed: american fossil mammals similar yet different from present-day llamas, sloths, and armadillos. Galapagos finches and giant tortoises vary between islands but generally resembles ones from s. america. Observations convinced darwin that organisms descended with modification from ancestors that lived during past. Unifying theory that explains otherwise simple collection of facts. There are no transitional fossils - so-called missing links - connecting ancestors to descendants. Humans evolved from monkeys so monkeys should no longer exist. Early ideas of evolution date to ancient greece but literal biblical descriptions for development of life prevailed until mid 19th century. Changing view of earth eg uniformitarianism, paved new intellectual path of theories. Jean-baptiste de lamarck (1744-1829) - developed theory: inheritance of acquired characteristics. New traits in organisms arise because of needs and somehow passed on to their descendants. Was widely accepted - not fully refuted until shown that genes not changed by effort of organisms.
