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ISB 201 1st Edition Lecture 7 Outline of Last LectureI. Quiz QuestionsII. ReproductionIII. ExoskeletonOutline of Current Lecture I. R vs. K SelectionII. Natural Selection Current LectureI. R vs. K SelectionA. R Selection (Really don’t care) ex: aphids 1. Smaller organisms2. Many offspring3. Little parental careB. K selection (Kare) ex: humans, elephants1. Larger organisms2. Few offspring3. More parental careC. Graph: Carrying Capacity v. Time1. R fluctuates over the carrying capacity over time; environment cannot always sustain mass populations (feast and famine)2. K increase towards carrying capacity then stabilizes a. Environment pushes back when populations increase over carrying capacityD. Where do insects fit in?1. Can be one or the other or bothII. Natural selection those organisms best fit to exist under current conditions survive AND reproduceA. Sexual selection reproductionB. Best fit a combination of genetic material that gives an organism an advantage over others in the population1. there are beneficial and non-beneficial mutationsC. 3 forms of natural selection1. Directional selection a shift in the frequency of a trait in the response to the environment (bigger/smaller)a. a fish gets lighter and lighter with time b. a snail shell gets darker and darker in response to volcanic activityThese 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.c. winner of genetic mutation is the winner and reproduced. Gertrude McFuzz not all changes are advantageous 2. Stabilizing selection an optimal value of a trait within a population. Extremes decrease from genetic poola. Avg. value/ trait preferred b. Not a lot of variation for thickness of egg shells… CONSISTENCY c. Sloths give births to twins, but one doesn’t survive- cannot catch the second up in the trees after giving birth3. Disruptive selection extremes of a trait are advantageous and the avg are selected against. Way of eliminating middle values from gene poolsa. could lead to development of a new population or speciesb. peppered moth mutations of all black and all white-black in response to industrial revolutionc. leaf cutter ants have 3 different size ants for different jobs, but all survive


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