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Unformatted text preview: Evolution and natural selection What is evolution? Changes in allele frequencies of a population over generations Macro/micro Aristotle Greek philosopher Scala naturae great chain of being No mechanism proposed Fossils were former life George-Louis Buffon (1707-1788) French naturalist Earth was very old (70000 yrs) Influence of environment on modifications on animal form Jean-Baptiste Lamarck (1744-1829) Fossils were remains of extinct animals Inheritance of acquired characteristics Emphasized great age of the earth Ideas almost universally rejected Charles Lyell (1797-1875) Supported uniformitarianism o Historical and physical continuity of nature Principles of geology Small forces acting over long periods of time Stressed great age of the earth influenced Darwin Charles Darwin Born in 1809 o Son of a physician Studied medicine in Edinburgh Studied theology at Cambridge Interest in natural science Served as unpaid naturalist on the H.M.S Beagle at age of 22 o 5 year voyage What Darwin saw Characteristics change place to place Great variety of organisms on young volcanic islands o Resembled forms on mainland Return to England Artificial selection- humans are selectively breeding to get desired characteristics Ideas of Thomas Malthus o Essay on the principle of population o Populations increase beyond ability of environment to support Origin of species in 1859 (book) Alfred Russel Wallace (1823-1913) British naturalist o Stationed in Malaysia o Studied insects Wrote to Darwin o Prompted Darwin to write On the Origin Of Species Two theses in the Origin of Species All organisms have descended with modification from common ancestors Chief agent of modification is action of natural selection on individual variation What is Natural Selection?...
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