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Barrett Ricklef Chapter notes.docx

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Barrett Ricklef Chapter notes (examples related to materials on lecture) Chapter 6 Pg 118, California citrus pest - farmers tried to control scale populations by fumigating orchards with cyanide gas - scale insects had evolved a genetically based resistance to cyanide poisoning - alleles that confer resistance to cyanide were at low frequencies in populations (recurrent mutations) - with cyanide fumigation, gene for cyanide resistance = higher fitness increase in #s pg119-120, field cricket - in Hawaii, field cricket coexisted with parasitoid fly - parasitoid fly home in on the cricket;s mating call to locate hosts - female flies lay their eggs in the cricket and the cricket is eaten from the inside out by the developing fly larvae - male evolved to be silent (a mutant allele that make a change in the structure of the wings) - a few calling males remain and the silent ones tend to gather around them and attempt to mate with females that are attracted by the calls pg121, African estrildid finch - shows disruptive selection in beak size - large beaks can crack open harder seeds - smaller beaks can open soft seeds more efficiently pg121-122, peppered moth - an example of industrial melanism - in the absence of factories and heavy industry, pale form of moth prevailed - in cities and heavily industrialized regions, dark form increased - inherited trait determined by single dominant allele - with less air population the number of the pale form increased again and the dark form decreased (SO con2entration dropped=melanistic moth frequency dropped) pg 124, Cactus wren - the wren had no source of drinking water and must avoid gaining too much heat from environment - it seeks favourable microhabitats within which to feed as the temp of environment change throughout the day - cool early morning everywhere, forage on ground; warmer during the day shades of small trees and large shrubs (not exceeding 35 C); over 35 C  stops feeding and perch quietly in deep shade because need to use evaporative cooling Makes different nest during different time period to help chicks stay cool: - Early spring (cool weather): entrance face away from direction of the cold winds - Hot summer: entrance face prevailing afternoon breezes (circulate air through nest to facilitate heat loss - Example of more general ability of the phenotype to respond to variation in environment (phenotype plasticity) Pg 126, swallowtail butterflies - Example of reaction norm - Larvae from Alaskan grew more rapidly than those from Michigan populations at low temperature - Larvae from Michigan grew more rapidly than those from Alaskan populations at high temperature Pg127, creosote bush - Example of acclimatization - 3 different species of plants photosynthesize optimally under different leaf temperature - Acclimatization may reflect range of conditions in its environment - Larrea = seasonal climate; atriplex = cool climate; tidestromia = hot climate Pg 128, African grasshopper - Example of irreversible developmental responses - Most grasshoppers complete their life cycles within a single season - Pigment systems in the epidermis develop in a way that the nymphs and adults match the background colouration of environment (to avoid predators) - Wet season  green; dry season brown; end of dry season burning black Water flea (Daphnia) - Develops hard cases over their heads (helmets) and long tail spines when there is a certain predator chemical in the water - Example of irreversible developmental responses Pg 129, eastern fence lizards - Example of reciprocal transplant experiments (nutrient poor from New Jersey and nutrient rich from Nebraska) - Put one to grow in the other’s natural environment - Result revealed both genetic determination and phenotypic plasticity - Nebraska lizards =2X faster than New Jersey ones in native environment - Nebraska  New Jersey = growth rate decreased by half (New Jersey level) - New Jersey  Nebraska = did not grow any faster - New Jersey lizards have a genetically regulated growth rate that is adopted to a low resource level - Shows that organisms may have little control over their rate of growth under poor conditions Chapter 13 Pg 274, monkey flower - Example of inbreeding depression - Selfed populations shoed a progressive reduction in ovule number and in male fertility over 5 generations - An increasing number of deleterious recessive alleles were exposed as the proportion of homozygous genotypes increased with each generation Pg 275-276, grey wolves - Inbreeding coefficients were very high (0.41) when the number of population was extremely low Banksia (Australian shrub) - Example of inbreeding depression and selective abortion in plants - Plant can self pollinate but normally outcross - Fruit production appears to be resource limited rather than pollen limited - Plant was fertilized with either pollen from itself or from neighbouring plants; counted fruits and seeds on each half of inflorescence - Self-pollination reduced # of seeds produced by 38% and increased the proportion of deve
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