Exam 1 Class Notes

Exam 1 Class Notes - Chapter 22 Descent with Modification:...

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Chapter 22 Descent with Modification: A Darwinian View of Life - o Evolution : 2 main ideas Change over time of the genetic composition of a population Descent of modern organisms with modification from preexisting organisms (We extract way far enough, which life began on earth, that we have a common descendants of ancestors, diversity of life. Gene frequencies) o Evolutionary adaptation Accumulation of inherited characteristics that enhances organism’ ability to survive specific environments - Pre-Darwinism Theory of Evolution o Jean-Lafitte Lamarck o Inheritance of acquired characteristics Bodies of living organisms are modified through the use of disuse of parts These modifications are inherited by offspring This idea turned out to be wrong (because we know a lot about genes) (giraffes ancestors were much shorter, modern giraffes have longer legs and longer necks because of the long lifetime of stretching) - Evolution by Natural Selection o o Darwin – voyage of the Beagle (right out of college & changed the world. Collect rocks & things along the way. Over time, he made a lot of observations. Species don’t fit, they change over time, share a common ancestor. Worked out a mechanism to see how changes occur) o Wallace – naturalist in Indonesia (collected birds and saw many mosquitoes, a lot of malaria. Natural selection and passed it on it Darwin to check) - Natural Selection o The unequal survival and reproduction of organisms due to environmental forces, resulting in the preservation of favorable adaptations o Process “selects” from what is available in the gene pool o New characteristics are NOT created on demand (traits LESS favorable are NOT likely to be passed over time) - Mechanism Behind Natural Selection (pg 458) o Potential for rapid reproduction (Relatively constant resources and population size over time) Competition for survival and reproduction (Variability in structure) Natural Selection : On the average, the fittest organisms leave the most offspring Evolution : The genetic makeup of the population changes over time, driven by natural selection - (Changing environment may have traits to move on; those that survive and reproduce will have the more impact on the genes.) - Unequal survival bc they have traits and passes on their genes to individuals - Artificial Selection o Selective breeding of organisms to encourage the occurrence of desirable traits o Analogous to natural selection o (Livestock animals, crops. Takes offspring that posses certain traits and breed.) Ex: wild mustard terminal bud, Brussels sprouts, broccoli, cauliflower 22.3 Evolution is supported by an overwhelming amount of scientific evidence - Examples of Natural selection (figure 22.13) o Experimental transplant of guppies Q: Within a few weeks of treatment with the drug 3TC, a patient’s HIV population consists almost entirely of 3TC-resistant
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This note was uploaded on 02/08/2012 for the course SCIENCE 1201 taught by Professor Bill during the Spring '11 term at LSU.

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Exam 1 Class Notes - Chapter 22 Descent with Modification:...

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