Unit 1 - Chapter 22 - Biology 1202 I. Descent with...

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Chapter 22 - Biology 1202 I. Descent with Modification: A Darwinian View of Life a. What is evolution and adaptation? There are 2 main ideas: i. Change over time of the genetic composition of a population ii. Decent of modern organisms with modification from preexisting organisms b. Evolutionary adaptation i. Accumulation of inherited characteristics that enhance organism’ ability to survive in specific environments 1. Example: humans becoming taller over time II. Pre-Darwinian Theory of Evolution a. Lamarck i. Inheritance of acquired characteristics 1. Bodies of living organisms are modified through the use or disuse 2. Until this time they haven’t been able to satisfactory explanation that organisms do evolve and how they evolve 3. These modifications are inherited by offspring 4. Giraffes a. In the past giraffes were shorter with shorter necks. Lamarck hypothesized that they spent their lives stretching their legs and necks, they passed on that longer gene to that offspring allowing them to reach the tops of the trees for food! i. This idea turned out to be wrong III. Evolution by Natural Selection a. In the middle of the 1800s, Charles Darwin published the book that gave us a better explanation with changes through organisms over time from one generation to the next. Darwin graduated from college and got a job as a ships naturalist, HMS Beagle, and spent 5 years mapping the coast of South America. After this, he collected his ideas proving evidence that organisms may not be static, but a change over time.
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b. About 20 years later, Wallace was in Indonesia and made some of the same observations and same conclusions. c.
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This note was uploaded on 02/26/2009 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Unit 1 - Chapter 22 - Biology 1202 I. Descent with...

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