BIo 207 Week 9 Lecture Notes
BIo 207 Week 9 Lecture Notes 207/41320
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This 6 page Class Notes was uploaded by email@example.com Notetaker on Friday November 6, 2015. The Class Notes belongs to 207/41320 at University of St. Thomas taught by Lewis in Summer 2015. Since its upload, it has received 21 views.
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Date Created: 11/06/15
Biology Week 9 Lecture Notes 0 Hutton geologist who proposes principle of gradualism Previous idea of catastrophism catastrophic events occurred long time ago in one time frame Hutton proposed gradualism things progresshappen slowly over time o Matthus economist who published essay on Principle of Population 0 Lamarck predecessor to Darwin on evolution Evolution occurred because of the passing on of acquired traits Experiment with rats cutting off tails to see if it passed on to the next generation proved Lamarck to be slightly wrong Epigenetics is Lamarckian evolution Don t define it as evolution though because it is not a change in the genes just the readability of them 0 Darwin goes on trip uses Wallace s theory of Evolution and gets published 0 Hypothesis thing you can test in an experiment 0 Theory generally accepted explanation for a phenomenon Scientists don t pursue truth in philosophical way only to be less wrong 0 Paradine theory so widely accepted everyone assumes it is true ex gravity 0 Key in science Predictability o Stratigraphy Younger stratum with more recent fossils topmost layers Older stratum with older fossils bottom most layers Natural selection leads to descent with modification everything in biology depends upon this Traits disappear as embryos develop Turtle shell modified ribs Scientist s don t deal with truth deal with predictability Strat from scratch similarities coincidence Descent with modification the order is the same Phylogenetic tree used to trace family lineage Should be able to predict descent with modification using this Birds are a part of the reptilian group subset of lizard Mammals are more closely related to reptiles than amphibians are Humans cats whales bats etc all have the same bones but evolved differently Making from scratch leads to no useful predictions Same bones modified to do different things ex pelvis Vestigial Structure no longer serves original purpose serves no purpose Will be gone if it serves no purpose Serves a different purpose 9 re modified Example in humans appendix Animals cannot digest cellulose the bacteria do Small intestine nutrient absorption Large intestine water absorption Horses hind gut fermenters Appendix withering away cecum humans used to be hind gut fermenters now appendix houses microbes Whales have pelvis vestigial Humans rudimentary ear muscles tail vertebrae o Convergent evolution very different lineages evolve similarly Ex squirrels sugar glider and flying squirrel analogous and homologous Evolved separately modification independently producing similar traits Ex birds and flying insects NOT homologous Ex our eyes and squid s eyes analogous o Analogous does the same function but not of the same origin 0 Homologous same structure of the same evolutionary origin 0 To get a new species Isolation Time 0 Geological evidence is found in layers New Species o Macroevolution new species develop over a large amount of time o Microevolution evolution on a smaller scale 0 Evolution a change in the gene allele frequencies List of Isolation 0 pre fertilization geographical physical behavioral temporal timing season time of day chemical 0 post fertilization F1 generation not viable F1 sterile Gene swamping no other hybrids to mate with o Directional over time the mean shifts Due to one extreme selected against 0 Stabilizing selection stabilizes about that trait One extreme selected against 0 Disruptive selection very isolating majority selected against Speciation o Allopatric speciation occurring in separate geographic locations 0 Sympatric speciation occurs in the same geographic location separated by all other types of isolation other than geographic Hardy Weinberg o Assumptions allele frequencies don t change unless something changes 0 5 things that can cause change 5 mechanisms of evolution 0 assumptions that lead to no change No natural selection resources are finite 9 competition individuals vary some variation is useful No net mutations change in chromosomes base pair mutations etc Net population Population group of interbreeding individuals with shared genetic material gene pool No net migration For whatever trait nose size those with a big nose are as likely to go as they are to come If big nose size likely to leave the population 9 net migration occurs No drift Sampling error The bigger the group the more accurate sampling Bottle neck effect too small of a group didn t represent group as a whole Sexual Selection Females select males based off of nose size Rapidly change gene frequency huge impact on evolution Males select for face symmetry child bearing ability wide pelvis Females select for strength and ability to gather resources fat deposits Pheromones hormones you put out in the world for others to deal with Hardy Weinberg Equation ab1 a percent of dominant allele b percent of recessive allele a bquot2 1quot2 9 aquot2 2ab cquot2 1 question if an allele goes from 9 and 1 frequency to a 8 and 2 frequency what must have happened Evolution Natural selection net migration sexual selection etc If the population is 6 what is the other allele frequency 4 Examples Ear Rotation p have it q don t P 52 q 48 Pquot2 27 qquot2 23 2pq 50 If 372 individuals are in this population how many are heterozygous 372 X 5 186