biol ch 14-17

biol ch 14-17 - Principles of Evolution What is Evolution o...

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Principles of Evolution What is Evolution? o Change in the proportion of genotypes in a population of time With time measured in generations o Descent of modern organisms with modification from preexisting organisms o All organisms come from a common ancestor Misconceptions About Science and Evolution o Scientists PROVE things Scientists are not always right o Evolution is “just a theory” Theories- general explanation of natural phenomena that has been tested over a long period of time o Science v. Religion Science is good for explaining the natural world Religion is good for explaining the supernatural world o “Intelligent Design” is a scientific theory Intelligent Design is not a theory Scientific Assumptions o All events can be attributed to natural causes Explanations don’t invoke supernatural causes Creationism; Intelligent Design o Natural laws apply at all places and all times o People perceive events in similar ways Exploration of new lands = staggering number of species o Similarities among species led to thoughts that they could change o Similar species are descended from a common ancestor Fossil discoveries showed that life has changed over time o Cuvier-Catastrophism Catastrophes caused extinct species and strata Where were fossils of species that are around today? o Agassiz-new creations 50 different creations? o LeClerc Creation of small number of organisms which evolve over time Old Testament said that Earth 4000-6000 years old; not old enough Geologists showed that the Earth is Old o Huttan and Lyell Uniformitarianism- slow natural forces caused stratification of rock
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Observations of geological formations x rated of processes occur = Earth at least millions of years old Plenty of time for evolution to occur, but still need a mechanism Pre-Darwinian Theory of Evolution o Lamark Inheritance of acquired characteristics Bodies were modified by the use or disuse of parts These modification are inherited by offspring This idea turned out to be wrong o Darwin and Wallace Evolution of Natural Selection Darwin voyaged the Beagle Wallace was a naturalists in Indonesia Darwin’s Finches Some lived on the ground others in trees Some had strong beaks while others had weak beaks Some ate insects while the others ate leaves Figure 14-4 How does Natural Selection Work? o Natural Selection The unequal survival and reproduction of organisms due to environmental forces, resulting in the preservation of favorable adaptations Process “selects” from what is available in the same pool New genes are not created on demand o Mechanism behind Natural Selection Figure 14-5 How do we know that Evolution has Occurred?
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This note was uploaded on 04/28/2008 for the course BIOL 1001 taught by Professor Minor during the Fall '08 term at LSU.

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biol ch 14-17 - Principles of Evolution What is Evolution o...

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