Lecture 2 ANTH 170c1 Outline of Last Lecture I Define Biological Anthropology II What is the theory of natural selection III What are the 3 necessary and sufficient conditions for natural selection IV Natural selection does act on humans V What are the 3 conditions for natural selection VI Is Natural Selection synonymous with evolution Outline of Current Lecture I Adaptation II Three categories of natural selection III What are the 3 necessary and sufficient conditions for natural selection III Stabilizing selection IV Directional selection V Disruptive selection VI Ways of describing traits Current Lecture Title Adaptation I Adaption A They increase your chances of surviving and reproducing B How can we tell if a trait is adaptive 1 If theirs more of then one trait 2 We can measure reproduction successful 3 Number of offspring or number of grand offspring etc related term fitness Evolutionary scientists often use this II Three categories of natural selection A Directional selection 1 Selection against one extreme not the other moving from one color to another Ex darker ones mice are in hotter environments B Stabilizing selection 1 Selection for the mean selection against extremes C Disruptive selection 1 Where individual have the lowest fitness selection against the mean selection for extremes ex light ones could be that the light colored mice that only like to mate with the light once same goes for the dark mice III Stabilizing selection A Selection for the mean 1 Outliers in the population are selection against ex body size fertility height IV Directional selection A selection against one group of outliers ex light and dark moth the human brian speed in prey animals V Disruptive selection A splits original distribution into two rare in nature 1 wherever 2 forms have evolved from one Big question why do we walk up right we do we have thumbs EEA environment of evolutionary adaptedness VI Ways of describing traits A Homology homologous traits ex mammary glands in monkeys B Analogy analagous traits ex wings on birds and bats brain in humans and dolphins 2