ANTH 1102 1st Edition Lecture 5 Outline of Last Lecture I Continuation of Forces of Microevolution and Macroevolution a Darwin s 3 observations b What Darwin didn t know c Mutation A force of Microevolution Outline of Current Lecture I Continuation of Microevolution and start of Macroevolution and human variation and adaptation Current Lecture Last Two Forces of Microevolution and Macroevolution Gene Flow Only affects population not species Random in effect on gene pool Migration movement of genes between breeding populations ex moving to a new community Increases diversity within a population More reproductive possibilities to allow populations to survive Genetic Drift Random in effect of gene pool Random reduction in diversity of alleles in a population Decreases genetic diversity in breeding populations Isolation of populations genetic bottleneck events Bottleneck events reduce population size decreasing genetic diversity and adaptability Restricts reproductive success of large population Humans are believed to share the same traits because of a bottleneck that occurred long ago Toba Disaster About 70 000 years ago Volcanic super eruption 6 10 years of volcanic winter Global change Reduced human species to about 10 000 Founder Effect A population with few individuals with genetic information that stays in isolated place Never reabsorbed into general population Small genetic endownment Ex Inbreeding religious communities Macroevolution Forces of microevolution are forces of macroevolution Accumulative changes Different patterns of speciation or transformation in species Allopatric When phenotypic changes occur by a physical or geographic separation Sympatric change over entire geographic range of a species time dependent Parapatric the changing of individuals within a population so they are no longer part of the same species Common Misconceptions Evolution is teleological displaying or connecting to design or purpose in nature NO All traits can be explained from the perspective of adaptation NO Our bodies are programmed for the Paleolithic denoting the early phase of the Stone Age NO Genes are paramount in evolutionary change NO Human Variation and Adaptation It s bio cultural External features and internal features Communities not genetic population Variation due to interactions among factors Genetic o Ex Variation in height genetic o Such as Wadlow an 8 1 man with a genetic mutation that allowed him to keep making growth hormones Environmental o Ex Variation in height non genetic o Growth stunting could be caused by factors such as o Nutrition o Stress emotional or social o Prenatal Environment o Chronic infections o Intestinal parasites o Environmental factors strongly influence genetic variations o Biological Plasticity Changes in biology due to environmental changes or stresses Sociocultural o Ex Variation in height cultural behavioral o Group level or individual behavior o Such as Paraca skulls and mummy s head shapes resulting from head binding o Changes in anatomy due to corsetry Adaptation is a major source of human phenotypic variation Genetic changes microevoluntionary Acclimatization non genetic physiological changes may be temporary or permanent can be inherited Ex goose bumps Individual behavioral changes Ex putting on a coat Cultural group level behavioral changes Ex drought Maintained or changed by selection or based on preferences accidents NOT ALL VARIATIONS ARE ADAPTED Just random Adaptation to Temperature Bergman s Rule body shape Variation in body build Slender warmer climate Stalky colder climate Surface area adaptability High surface area lose heat Low surface area heat retention Allen s Rule Mammals and birds protruding body parts Longer in warmer climates Shorter in colder climates Acclimatization temporary changes Efficient shivering Goose bumps Lewis hunting cycles
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