WILD 3580 1st Edition Lecture 6 Outline of Last Lecture I Phylogenetic Classification II Species III Isolating mechanisms IV Phylogenetic species concept V Genetic species concept VI Taxonomy about the Species Level VII Trinomial Nomenclature Outline of Current Lecture I Rules of geographic variation II Vertebrate Evolution and Speciation III Selection Pressure Current Lecture I Rules of geographic variation a Bergman s Rule geographic races of endotherms tend to possess smaller body sizes in warmer portions of their range and larger body sizes in cooler climates Surface area to volume ratio larger things have less volume per surface area lose heat b Corollary to Bergman s rule geographic races of ectotherms tend to possess larger body sizes in warmer portions of their range and smaller body sizes in cooler climates Smaller sizes can absorb more heat c Allen s Rule the extremities of endotherms tend to be longer in warmer areas and shorter in cooler areas In warmer climates can get rid of heat faster These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute d Gloger s Rue geographic races of endotherms in arid regions tend to be lighter in color than those in humid regions Camouflage Darker colors absorb heat lighter colors reflect heat e Clutch Size Rule geographic races of birds in warmer areas tend to have fewer eggs per clutch than races in cooler areas Lower survival rate in cooler areas adaptive compensation II III Endotherm maintaining a high constant body temperature through metabolism Ectotherm regulating body temperature through behaviors Vertebrate Evolution and Speciation Natural selection nonrandom reproduction of organisms that result in the increased probability of survival of individuals that are best adapted to the environment o Fitness successful reproduction genetic contributions to successive generations Trends of evolutionary change 1 Directional gradual change a Ex Cheetahs have grown smaller over time 2 Divergent change a Populations adapt to local conditions b Divergence accumulation of genetic changes through time c Ex Squirrels at the Grand Canyon 3 Adaptive Radiation a Diversification into different ecological niches by species derived from a common ancestor b Ex Darwin s finches Selection Pressure An aspect of the environment that influences survival and reproduction in the population
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