Anth 5 - Intro to Biological Anthropology with Professor Gaulin
Anth 5 - Intro to Biological Anthropology with Professor Gaulin 00372
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This 4 page Class Notes was uploaded by Brittnee Zuckerman on Sunday October 19, 2014. The Class Notes belongs to 00372 at University of California Santa Barbara taught by Gaulin in Fall2014. Since its upload, it has received 149 views. For similar materials see Anth 5 - Intro to Biological Anthropology in ANTH at University of California Santa Barbara.
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Date Created: 10/19/14
ANTH 5 Intro to Biological Anthropology Week 1 10714 What are the mechanisms for natural selection How is the organism able to obtain or develop these characteristics that will give them an advantage in their environment The central problem How does natural selection solve the central problem Does an organism develop these adaptive characteristics over time o No a species evolves them over the generations because some individuals leave more offspring than others Genetic recipe as a self assembly formula Self assembly development Evolution refers to changes in the frequency of different traits over time Why do adaptations exist Do adaptations ever hinder an individual s chance of survival 0 Adaptations that harm survival could be favored be selection if they sufficiently increased reproduction The only thing that39s around today is the descendence of individuals who survived today Traits that often inflict costs in the realm of survivor will be favored by natural selection a peacock s tail What good is the peacock s tail It is a trait that promotes reproduction Does it make sense to think of selection as a spontaneous natural process that reduces entropy increases order 0 Yes Entropy can be thought of as a measure of randomness or disorder The natural tendency of the universe is towards disorder increasing entropy What is non random in the evolutionary process described by Darwin and Wallace 0 Which individuals survive and reproduce Are all members of the population contributing to the next population 0 The core of the idea of natural selection is that nature is selecting the ones that fit best with that particular environment allowing them to reproduce Non random how well they pass the test of environment And how does that decrease entropy o More precisely ordered designs are differentially perpetuated In terms of human population what happens when disadvantageous traits begin to reproduce as fast as advantageous traits because of all the resources and technology we have built today 0 Selection does not care which species is stronger 0 You39re not allowed to define disadvantageous and advantageous traits from your personal moral judgments because it is natural selection 0 An advantageous trait just means the ability to reproduce o If it39s good at getting into the next generation it39s advantageous o Humanity does not decide nor know what39s good or bad it is entirely up to nature o Our human evaluations of what is good and not good is not the standard of how selection operates Regarding humans in the natural selection process would all the advancements in medicine hinder the natural selection process since the diseases with undesirable traits are being treated Female song sparrows are most likely to survive if they are average sized o What might be good about being average average sized infants also do best o Average is where it is because of a history of selection weeding out what wasn39t good o Organisms are the way they are because of what worked in past Had to succeed in the past to get into the next generation Is it possible to create a controlled environment where a life form no longer needs to rely on the idea of natural selection and evolution o What will be controlled 0 Will some reproduce more than others 0 What about individuals with harmful mutations o How could you stop natural selection I Selection will weed out the bad mutations I Any time there is differential reproductive success all the time natural selection is operating Natural selection is always occurring Essential elements of natural selection o Heritable traits some of which get passed on more often than others work better Scientists are looking at change across the generations and scientists look at what descendants are like Selection only favors the traits that are good FOR getting into the next generation 10914 Watched a short video of the Valley of Fire in New Mexico Selection is driving changes and different selection pressures are in the environment selection is not creation It can only choose from alternatives that already exist Initial dark coloration is rare or random mutation Dark coloration spreads because initially rare dark mice have more offspring highly non random natural selection Convergence other lava areas have also selected for dark mice Different mutations occurred in different lava areas Is a trait only labeled as advantageous when it is successfully passed from parent to offspring o advantageous is relative Something is only advantageous compared to something else ex dark vs white 0 advantageous is comparative there is no absolute best Could homosexuality be considered an advantageous trait even if it may hinder reproduction benefical for counter overpopulation preserving natural resources What is the evolutionary purpose for species that have the homosexuality trait The consequences of a trait for the species as a whole are irrelevant to whether or not the trait will spread Will selection favor traits that reduce overpopulation Imagine two types one of which reproduces less to avoid population and one of which rears as many offspring as it can All that is important is does the gene that causes the trait good at getting into the next generation Selection favors what39s good at getting into the next generation NOT what39s good for the species Microevolution and Macroevolution Microevolution generation by generation changes in gene frequency Happens in ecological time A one generation change in a trait Could be measured at the level of the trait or at the level of the genes causing the trait Macroevolution large scale changes in species over geological time The emergence of distinct new species iClicker questions A sparrow wing and a penguin ipper are homologous because they have the same structure bones muscles etc What is significant about homology 0 It suggests that selection works with existing variation Sidenote you cannot PROVE evolution or anything there is no scientifically proven or a particular hypothesis is the correct explanation scientists basically disprove bad theories and if all these are not the case it must be this Uniformitarianism a principle way of thinking intellectual business It is not that the world is always the same it is that the forces that operate in the world are constant The processes that cause species to change is uniform the genetic code the passage of hereditary information the process of selection etc requires that hypothesized casual forces be observable Gradualism argues that smaller mutations have the best chance of being favored by selection Two implications of gradualism The formation of complex adaptations today The formation of new species later ALL TRAITS HAVE COSTS It costs you to build a bill There is no free lunch Any favored trait is favored simply because its reproductive benefits outweigh its reproductive costs If mutations are random then how is selection so precise as in the case of the orchid mantis 0 Because selection is NON random and it operates generation after generation retaining anything that helps contributes to reproductive success How efficient are mutations at creating biodiversity in a species and optimal changes in an organism o efficient refers to something designed mutation is not a design feature mutation is entropy What about complex adaptations the eye How can small mutations build such a structure Wouldn39t it take one giant mutation o Selection has no foresight o It retains any variant that is currently useful with different eye elements gradually accumulating o No trait will spread unless it confers an advantage in the present 0 So complex adaptations must be built of small changes each of which is beneficial at the time it occurs