Lecture 2: Natural Selection

StudyBlue printing of Lecture 2: Natural Selection html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; background: transparent; } body { line-height: 1; } blockquote, q { quotes: none; } blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; } /* remember to define focus styles! */ :focus { outline: 0; } /* remember to highlight inserts somehow! */ ins { text-decoration: none; } del { text-decoration: line-through; } /* tables still need 'cellspacing="0"' in the markup */ table { border-collapse: collapse; border-spacing: 0; } /* end RESET */ .header { min-width:800px; } .logo { padding:6px 20px 2px 20px; margin:0; font-size:25px; font-weight:bold; color:#808285; position:relative; border-bottom: 1px solid #c5c5c5; } .logo-blue { color:#70adc4; } .logo-desc { font-weight:normal; font-size:19px; color:#cccccc; margin-top:50px; position:absolute; display: none; } .back-button { position:absolute; top:20px; right:20px; font-size:13px; line-height:25px; color:rgb(0,175,225); font-weight:normal; } .back-button a { color:rgb(0,175,225); } .instructions { padding:0; margin:0; width:100%; position:relative; color:rgb(100,100,100); } .step-holder { border-left:1px solid #ededed; margin-left:20px; } .steps { padding:15px 0; float:left; width:24%; border-right:1px solid #ededed; text-align:center; } .steps-01 { } .steps-02 { } .steps-03 { } .steps-04 { } .label { padding:5px 10px; } .print-button { } .print-button a { background-color:rgb(0,175,225); color:white; line-height: 19px; padding:9px 8px 5px 30px; font-size:14px; text-decoration:none; background-image: url(images/printer.png); background-repeat: no-repeat; background-position: 7px 50%; -moz-border-radius: 5px; -webkit-border-radius: 5px; } .print-button a:hover { background-color:black; } .theNote .content { width: 8.0in !important; margin: 5px auto; padding:20px; background-color:white; } .theNote .header { border-bottom: 1px dashed #C8C8C8; font-size: 17px; padding: 0 0 10px; line-height: 19px; color: #00ADE1; min-width:500px; } .theNote .body { font-size: 14px; line-height: 19px; padding: 10px 0; } .theNote{ padding:6px 0; clear:both; background-color: rgb(200,200,200); } .theNote h3{ color: rgb(100,100,100); } .theNote h1, .theNote h3{ background-color:white; padding:2px 20px; width:8.0in !important; margin: 0 auto; font-size: 15px; } .theNote h1{ padding-top: 10px; font-size: 15px; } .theNote h1:first-child{ font-size: 20px; } .theNote h3 { font-size: 14px; font-weight: normal; } #options { border: 3px double #ccc; padding: 5px 12px; margin: 10px 50px 10px 20px; float: left; } #info { border-top: 1px solid #ccc; padding-top: 5px; font-style: italic; } li { margin: 5px 10px 5px 25px; } ul li { list-style: disc; } ol li { list-style: decimal; } img { border: 0; } table { clear: both; width: 100%; border: 1px solid #c5c5c5; border-width: 1px 0; margin: 0; page-break-after: always; } table#page { page-break-after: auto; } td { text-align: center; font-size: 12px; border-bottom: 1px dashed #c5c5c5; height: 1.75in; width: 50%; padding-left: 15px; } .leftside { border-right: 1px solid #cccccc; padding: 0 15px 0 0; } .bottom td { border-bottom: none; } .clearfix { clear:both; line-height:1px; height:1px; } img { max-width:80%; max-height:150px; margin:20px; } @media print {.header { display: none; } .content .header{ display:inherit; } table { border: 1px dashed #bbb; border-width: 1px 0; } .theNote{ background-color:white; } } Why does "Nature" select? Over-reproduction + Limited Resources = Competition, suffering and death How does "Nature" Select? Variation + Heritability = most "favorable" traits survive (and passed down) variation- different genes, different phenotypes What is favorable? "Survival of the fittest"-- by Herbert Spencer fittest=best fit (not strongest, biggest fastest, smartest... etc.) Best fit changes with different environments "It is not the strongest of the species taht survives, no the most intelligent. It is the one that is most adaptable to change..." -Charles Darwin "On the Origin of Species" (1859) Evidence for Natural Selection Artificial Selection Fossil Record Biogeography Homology/Analogy Vestigial Organs Embryology --- 7. GENETICS: cornerstone that made it successful Artificial Selection (microevolution) species can change artificially by us. Can nature change species? Fossil Record fossil evidence Biogeography more similar individuals (or species) closer Less similar individuals (or species) further apart Species separated by natural barriers How would you test this concept? If species are created in each area, then... unable to live, adapt to new area If species expand into each area then... how did it get there? Homologous/Analagous Traits Homologous characteristics: same ancestor, different functions aka. Divergent evolution ex. arm bones in birds, whales, humans Mammals hair Analogous characteristics: different ancestor, same function aka. Convergent evolution ex. batwings, insect wings, bird wings aye-aye teeth/beaver teeth mammal hair and insect bristles Vestigial Organs Snake and Whale hips Eyes in cave-dwelling species Horse canines Humans: tonsils, wisdom teeth, body hair (erector pili), ear muscles, webbing, tailbone things we have, we don't necesarily need Embryology all very similar What Darwin Presented 1859 GENETICS!!! evolution explained by natural selection (1750-1859) Natural selection explained by Genetics (1859-1900) Genetics explained by DNA/ Transcription and translation (1900-1950s) Mutations (from genetics lecture) Single base mutations/ Multi-base mutation sexual recombination deletion insertion substitution translocation inversion (backwards) duplication Types of Natural Selection 1. Stabilizing (e.g birthweight) 2. Disruptive (e.g. mice, cacti) 3. Directional (rabbit, newt toxin) Coevolution Genetic Drift: Random Selection Genes slected by random chance founder effect (amish) bottlenecks (disasters and random survival) "candy natural selection" Key points: Natural selection Natural selection is a process (no goal; no endpoint) populations evolve, not individuals As environment changes, only survivors reporduce ("nature selects") Controversy: Eugenics forced sterilizations (1907-1974) criminals, epileptics, mentally ill, "misfit" families Racism and immigration nazi party is Eugenics=natural selection?? NO- it is selecting traits we want and getting rid of those we don't like.