Lecture 03

Lecture 03 - Lecture 03 // 10.02.08 - The History of...

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Unformatted text preview: Lecture 03 // 10.02.08 - The History of Evolutionary Thinking • What did Darwin say in the Origin? o All organisms evolved from common ancestor--descent with modification o Mechanism - natural selection • How were Darwin’s ideas accepted? o Descent with modification from a common ancestor was widely accepted soon after publication Could be reconciled with religious views Data were overwhelming o Natural selection- universally rejected for 50-60 years Seemed to prelude religious belief of divine purpose - no grand purpose to natural selection - irreconcilable Earth is not old enough for natural selection to create diversity we see today (10- 100 million years old) • Countered : Discovery of radioactivity and radiometric dating No understanding of inheritance • Blending inheritance- inherited characteristics are mixed like paint • Neo-Lamarckism was popular explanation for source of variation- inheritance of characteristics acquired in response to environmental conditions • Countered : Better understanding of genetics by Mendel o Parents pass discrete units of info to offspring o Concept of gene, recessive, dominant o Punctured idea of blending inheritance • Countered : August Weismann (German zoologist) o Heritable traits pass from generation to generation via material in nuclei of cells o Differentiated “germ plasm” (gametes) from somatic cells o Germ plasm is not altered by use Question : Why would the idea of “blending inheritance” contradict Darwin’s idea of evolution by natural selection? Blending inheritance decreases variation. Chapter 23 - The Evidence of Evolution • Evolution- change in the genetic composition (allele frequency) of a population over time (across generations) • Population evolve; individuals do not Question : Which of the following is evolution, in scientific term? Overview I. EVIDENCE OF CHANGE OVER TIME a. Fossil record i. Extinction ii. Law of succession iii. Transitional forms b. Vestigial organs I I. EVIDENCE THAT SPECIES ARE RELATED a. Evidence of common ancestry i. structural homology ii.ii....
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This note was uploaded on 03/31/2009 for the course BILD 632282 taught by Professor Henter during the Fall '08 term at UCSD.

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Lecture 03 - Lecture 03 // 10.02.08 - The History of...

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