Biology Chapter 22 Objectives

Biology Chapter 22 Objectives - Chapter 22 Descent with...

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Chapter 22 Descent with Modification: A Darwinian View of Life The Historical Context for Evolutionary Theory 1. The mechanism for evolutionary change proposed by Charles Darwin was natural selection. The basic idea of natural selection is that a population can change over generations if individuals that possess certain heritable traits leave more offspring than other individuals. 2. Evolution is a change over time in the genetic composition of a population. Adaptation is the accumulation of inherited characteristics that enhance organisms’ ability to survive and reproduce in specific environments. 3. Aristotle’s scala naturae states that life-forms could be arranged on a ladder or scale of increasing complexity. Carolus Linnaeus’ classification scheme group similar species into increasingly general categories. 4. Catastrophism speculates that each boundary between strata represents a catastrophe that destroyed many of the species living at that time. The periodic catastrophes were usually confined to local geographic regions, which were repopulated by species immigrating from other areas. Gradualism is the idea that profound change can take place through the cumulative effect of slow but continuous processes. Uniformitarianism proposes that the same geologic processes are operating today as in the past, and at the same rate. 5. The mechanism for evolutionary change proposed by Jean-Baptiste de Lamarck was comparing current species with fossil forms. Modern biology has rejected Lamarck’s theories because there is no evidence that acquired characteristics can
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This note was uploaded on 08/29/2009 for the course BIOL 101 taught by Professor Sakji during the Fall '08 term at Linn Tech.

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Biology Chapter 22 Objectives - Chapter 22 Descent with...

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