Bio 201 F09 True lect 4 (L4)v3r

Bio 201 F09 True lect 4 (L4)v3r - todays factoid 47 million...

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today’s factoid 47 million year old primate fossil the size of a small cat that was discovered in 1983 but until recently had been in a private collection was finally analyzed and published this year had been in two pieces, so significance was not known transitional form; in the lineage that eventually split to give rise to the monkey lineage and the great ape lineage (human lineage) nearly complete fossil many non-bone features preserved, including fruits, seeds, and leaves in its gut see 'Common Ancestor of Primates' posted in Biology in the News on BB
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History • Darwin – realized that varia5on occurs among individuals of a species • visible or physiological phenotypic traits • survival and reproduc5ve success ( ftness ). – recognized two broad classes of varia5on • “sports” • “individual varia5on” – thought this kind was more important He thought that most phenotypic evolu5on should be gradual
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History • However – source of varia5on unknown – mechanism of inheritance unknown •Darwin –Incorporated well known observation: •offspring tend to look like their parents •Darwin proposed “pangenesis” as the hereditary mechanism –Each cell of the body buds off a small piece, called a “gemmule”. These pieces congregate in the reproductive organs where they are incorporated into the gametes and transmitted to offspring. •Pangenesis -> “blending inheritance”
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Early 20 th century • Hereditary mechanisms con5nued to be debated through the late 1800s un5l Mendel’s studies were rediscovered at the turn of the century •Two schools of genetic thought emerged –Biometricians, or “natural inheritance” school –concentrated on continuously variable traits –e.g. height, weight –Mendelian, or saltationists –concentrated on large effect mutants and other traits that were inherited like the traits Mendel studied
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This note was uploaded on 12/22/2009 for the course BIO 201 taught by Professor True during the Fall '08 term at SUNY Stony Brook.

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Bio 201 F09 True lect 4 (L4)v3r - todays factoid 47 million...

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