Extinction+-+Lec+IB

Extinction+-+Lec+IB - EXTINCTION Lecture 1, Part B Fall...

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Unformatted text preview: EXTINCTION Lecture 1, Part B Fall 2009 Anthropology 070:111 NASA/courtesy of nasaimages.org Extinction Extinction • A set of facts we can know (“What?” questions) • A range of ideas answering Why? and How? And in this class…. And • Informed by the discipline of Anthropology Anthropology • And various subdisciplines including evolutionary anthropology • A challenge of the 21st century • Something which has meaning for people or people make meaning of Evolutionary Theory People (and Extinction) Scientific Method “Nothing in biology makes sense except in the light of evolution.” --Theodosius Dobzhansky Charles Darwin (1809-1882) Charles • contributes evolution by way of natural selection • builds on a few ideas in place beforehand Some of Darwin’s Influences Some Charles Lyell (1797-1875) -uniformitarianism -an old Earth Jean-Baptiste Lamarck (1744-1802) -inheritance of acquired characteristics Thomas Malthus (1766-1834) Thomas “The power of population is indefinitely greater than the power in the earth to produce subsistence for man. Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio. A slight acquaintance with numbers will show the immensity of the first power in comparison with the second.” --Thomas Malthus, An Essay on the Principle of Population, 1798 The Concept of Natural The Selection 4 Basic Observations Basic 2 Inferences Obs. 1: Populations intrinsically Obs. grow exponentially Another view: Populations Another intrinsically grow exponentially 1 2 4 8 16 32 64 128 256 512 1,024 2,048 4,096 8,192 16,384 32,768 65,536 131,072 262,144 524,288 1,048,576 2,097,152 4,194,304 8,388,608 16,777,216 Obs. 2: Resources are limited. Obs. We live on a ball slowly revolving….. The finiteness of resources appears fundamental. Inference 1 Inference There will then result “a struggle for existence”….. Observation 3: Variation Abounds Observation Observation 4: Traits are Observation heritable • More offspring will be produced than will survive (drives competition) / “struggle for existence” (Inference 1) Inference 2 • Individuals with favorable traits will have an advantage over others without those traits. • Survival is dependent on context • Those that survive will produce more offspring. “survival of the fittest” ??????? Fitness Fitness • a measure of reproductive success • effect of characteristic on reproductive success • An organism living half as long but have twice as many grandchildren has twice the fitness Sexual selection Female choice Male-male competition Scientific Method Scientific • The observation is…… -for example, lyrebirds have some amazing calls • Hypothesis (it might work this way) • Prediction (if it does work that way then…) • Tests of hypotheses The observation is….. (what is wrong with this picture anyway?) Hypothesis: Racehorses run so fast that they can fly. Prediction: At high speeds, horses feet do not touch the ground. An Experimental Test Result: The “flying horses” hypothesis is falsified. Comparative analysis ...
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