Mechanisms of Evolution I&II

Mechanisms of Evolution I&II - Mechanisms of Evolution...

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Mechanisms of Evolution I 24/01/2008 17:28:00 Most important mechanism of evolution is Natural Selection, because it produces  adaptation Other forms do exist and are important o Genetic drift Similar genomes among differently placed animals Interchange of information Can result from catastrophic extinctions Tends to work against genetic diversity The smaller the population the faster a trait is lost Chance differences in reproduction Founder events Bottlenecks Theory of Natural Selection is based on 4 observations o Populations of Living Organisms change over time Darwin set about proving that evolution occurred Evidenced in fossil record Evidenced his theories with ‘artificial selection’ o Darwin Worked with pigeons to breed certain traits Done since onset of agriculture Eg. Wild cabbage selected for ‘better’ traits o Organisms are good at what they do
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Beaks of birds Bald eagle for tearing flesh Curlew for fishing for crustaceans Roseate spoonbill for filtering o Organisms multiply in number Malthus research on famine resulting from multiplication Resources do not increase exponentially People do increase exponentially o Offspring tend to resemble their parents Darwin: Under increasing competition only a few organisms  survive and reproduce Variation occurs between individuals and can provide  advantage Heritable variations go on to offspring, survival traits  passed on Over a great deal of time many small changes can result in 
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Mechanisms of Evolution I&II - Mechanisms of Evolution...

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