WILD 3580 1st Edition Lecture 6Outline of Last Lecture I. Phylogenetic ClassificationII. SpeciesIII. Isolating mechanisms IV. Phylogenetic species concept V. Genetic species concept VI. Taxonomy about the Species LevelVII. Trinomial Nomenclature Outline of Current Lecture I. Rules of geographic variationII. Vertebrate Evolution and Speciation III. Selection Pressure Current LectureI. Rules of geographic variationa. 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 fasterThese 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 incolor than those in humid regions- Camouflage- Darker colors absorb heat, lighter colors reflect heate. 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) - Endotherm- maintaining a high, constant body temperature through metabolism - Ectotherm- regulating body temperature through behaviorsII. 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 change1. Directional/ gradual changea. Ex. Cheetahs have grown smaller over time2. Divergent changea. Populations adapt to local conditionsb. Divergence- accumulation of genetic changes through timec. Ex. Squirrels at the Grand Canyon 3. Adaptive Radiationa. Diversification into different ecological niches by species derived from a common ancestor b. Ex. Darwin’s finches III. Selection Pressure- An aspect of the environment that influences survival and reproduction inthe
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