ant201finalsg - Final exam ANT 201 Study Guide dumb Lecture...

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Final exam ANT 201 Study Guide: dumb Lecture 20: Modern human variation Microevolution - used to refer to changes in the gene pool of a population over time which result in relatively small changes to the organisms in the population — changes which would not result in the newer organisms being considered as different species. Examples of such microevolutionary changes would include a change in a species’ coloring or size. M acroevolution - used to refer to changes in organisms which are significant enough that, over time, the newer organisms would be considered an entirely new species. In other words, the new organisms would be unable to mate with their ancestors, assuming we were able to bring them together. - For biologists, there is no relevant difference between microevolution and macroevolution. Both happen in the same way and for the same reasons, so there is no real reason to differentiate them. When biologists do use different terms, it is simply for descriptive reasons. Human variation arising over the past 50 kya - People from one African population migrate to Eurasia and Australasia - Dispersed human populations diverge - Variations in morphology, physiology, and behavior Genetic and environmental influences on human behavior - Genetic variation o Differences caused by genes inherited from parents - Envrionmental variation o Differences caused by environmental factors and culture - In most cases, very difficult to disentangle genes and environment Plasticity = Functional adaptation Can refers to behavior Genotypic pleiotropy = Same gene can produce multiple phenotypes - Greater flexibility, adaptability to varied, unstable or fluctuating environments Role of selective forces in generating human variation - lactose intolerance o Correlates with access to sunlight/ other vitamin D sources o Vitamin D necessary to absorb calcium; sunlight passes through skin and produces vitamin o In northern latitudes, little sunlight leads to vitamin D deficiency and thus increased consumption of milk due to the Vitamin D and calcium it contains - blood types o Simple polymorphism o Bacterial v. Viral threats o Maternal-fetal incompatibility o ABO system - thermoregulation and Allen and Bergmann’s Rules o Living in warm climates tend to influence the presence of longer arms and legs while living in colder climates prefers rotund and short limbs o Allen’s Rule – In warm-blooded species, the relative size of exposed portions of the body decrease with decrease of mean temperature Long, slender arms and legs are increased by assuming more linear form
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Evaporation of sweat is greater than in any other animal, and evaporate loss is directly proportional to the amount of exposed surface area Lean and gangly – tropical climate; rotund and short limbed- arctic o Bergmann’s Rule – mammals get larger in cooler environments –body size usually increase with decreasing mean temperature of its habitat As body size increases
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