Mod. 1 Lectures 1-3
Mod. 1 Lectures 1-3 ASM 104
Popular in Bones, Stones/Human Evolution
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This 8 page Class Notes was uploaded by Gabrielle Hsu on Wednesday August 26, 2015. The Class Notes belongs to ASM 104 at Arizona State University taught by Campisano in Fall 2015. Since its upload, it has received 440 views. For similar materials see Bones, Stones/Human Evolution in anthropology, evolution, sphr at Arizona State University.
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Date Created: 08/26/15
MODULE 1 LECTURE 11a INTRODUCTION Goals of this lecture Contextualize historically amp socially the development and presentation of Charles Darwin s theory of evolution Understand the other ideas amp work that contributed to Darwin s theory Concepts explored in biological anthropology Relationships between different kinds of organisms Adaptations of those organisms MAIN IDEAS Timeline of ideas about life the natural world 1850s Charles Darwin s theory is introduced An increase in the popularity amp spread of evolutionary thought follows and there is a simultaneous fading though not dying out of belief in instantaneous creation or the Biblical v1ew What is natural selection Natural selection is what produces adaptations and drives evolution Changes in popular beliefs in Europe aboutviews of the natural world PreDarwin Biblical view predominates including two main schools of thought Essentialism a belief that all things have unchanging characteristics by which they are defined Ignores variation between different organisms of the same species focusing on the quotdefinitionquot of that species Teleology a belief that things were created to serve a specific purpose and that purpose is what defines them For example humans were put here by God for a reason and are higher than other beings PostDarwin Evolutionary thought becomes more popular Focuses on variation both within amp between species Nonstatic organisms can change over time Nonteleological things do not have a specific overarching purpose The Age of DiscoveryAge of Expansion Time of many European explorers such as Christopher Columbus Discovery of new cultures brought up problems such as slavery amp religion 1492 Columbus discovers the New World 1537 The Vatican declares that Native Americans have souls amp forbids their enslavement Sublimus Deiquot Led to the development of the field of natural history Creation of museums curios and the term exotic used to refer to anything thought of as strange or other such as people from different cultures Scala Natura The Great Chain of Being Goal of science at the time was to place things within this order with God at the top then angels then humans then mammals etc Class gender race etc were included as determinations of which people were higher in the order and therefore closer to God Popular thought about the age of the Earth 1800s and earlier Archbishop Iames Usher declared in 4004 BC that the Earth was about 6000 years old This belief persisted for many years Evolutionary theory contradicted this because the process of evolution would have taken much longer than 6000 years forcing reevaluation Earth is really 35 billion years old Summary of the preDarwin pre1850s mindset in Europe People thought The Earth was only 6000 years old This would not fit with evolutionary theory Species were created exactly as God meant and were unchanging All beings fit into a hierarchy in which some are closer to God MODULE 1 LECTURE 11b INTRODUCTION This lecture is a continuation of the previous lecture 11a It expands the timeline of ideas about life and the natural world and goes into more detail about the people who came before Darwin and introduced ideas that in uenced his work set the stage for the presentation of his theory MAIN IDEAS Carl Linnaeus mid 1700s Known for creating the system of taxonomy which categorizes organisms Published Systema Naturae or Systems of Nature which introduced the system Taxonomic categories move from least to most specific Kingdom Phylum Class Order Family Genus Species Binomial nomenclature uses the two most specific classifications genus amp species as the name for an organism o For example humans are referred to as Homo sapiens Homo is the genus which also includes extinct species like Neanderthals and sapiens is the species within that genus Linnaeus was a theological thinker not evolutionary He believed his work in natural history was ad majorem Dei gloriamquot or for the glory of Godquot William Paley early 1800s Published a book called Natural Theologyquot in 1803 Introduced the watchmaker argumentquot Because watches are so complex and designed for a specific purpose they can only have been created deliberately not randomly Organisms and systems within organisms such as the human eye are equally or more complex and therefore they must also have been created with purpose and for a purpose Today this idea is referred to as intelligent design GeorgesLouis Leclerc Comte de Buffon late 1700s Erasmus Darwin late 1700s Both Buffon and E Darwin were supporters of the idea of evolution but neither proposed any theory or mechanism for how evolution worked They are still significant because they were some of the earliest supporters of evolution E Darwin was a relation of Charles Darwin Lamarck early 1800s One of the first people to propose a theory for how evolution worked Inheritance of acquired characteristics This theory stated that animals develop new characteristics during their lifetimes in order to achieve some goal such as giraffes stretching their necks out to reach higher leaves These characteristics are then passed on to the animals offspring Cuvier early 1800s Theological thinker Introduced catastrophism Catastrophism was the idea that phases of geologic unrest natural disasters occurred periodically throughout Earth s history amp these led to the extinction of certain species Other species then replaced those This brought up important questions such as 0 Who did the replacing God migration something else 0 If Earth was only 6000 years old how could all of these periods of disasters amp extinction have had time to occur Charles Lyell Introduced uniformitarianism States that geological processes such as erosion formation of mountains amp rivers etc occur at the same rate now as they did in the past Because people could observe how slowly these processes were occurring logically Earth had to be much older than 6000 years for all of the existing geological features to have had time to form Iames Malthus Theological thinker Introduced an economic model of population growth Limited resources create competition within amp between species for those resources checking population growth SUMMARY Increasing exploration amp acceptance of these ideas Evolution Uniformitarianism Deep time belief that Earth was much older than previously thought Resource limitation and population growth MODULE 1 LECTURE 2 INTRODUCTION This lecture follows the historical amp social context given to Darwin s work by the previous two lectures by actually discussing the details of his theory including some examples of natural selection What is evolution Evolution is a change in allele frequencies within a gene pool over time Alleles and allele frequencies will be discussed in future lectures Where at what levels of population biology does evolution occur Individual does not occur Population a group of individuals does occur Species populations that have evolved to become too genetically different to interbreed does occur MAIN IDEAS Charles Darwin s trip around the world 1831 sailed on the HMS Bounty Visited the Galapagos Islands amp observed physical differences between the finches a type of small bird on each island Different beak shapes thought to re ect the environment available diet of the island Observations Population growth always surpasses the available resources Individuals within a population always vary from each other Differences are heritable passed down from parents to offspring Inferences Individuals with higher fitness meaning they have features better suited to their environment amp are therefore better at competing for resources are more likely to survive amp reproduce They pass on those features to their offspring who passes it on to theirs causing the population to change over time to have more individuals with those features This is adaptation Over a long enough period of time new species will evolve from adaptations What is fitness Fitness is an individual s relative reproductive success as compared to other individuals of the same species Survival of the fittestquot Fitness is not just about survival Some traits are good for survival but not for reproduction amp vice versa Ex bright plumage on birds attracts both mates amp predators Key points Natural selection occurs in individuals but evolution only occurs in populations and species Adaptation is to a specific environment at a specific time Natural selection is driven by variation amp cannot exist without it Hyperspecialization lack of variation is bad because if the environment changes none of the individuals may be fit for the new environment leading to extinction Harmful genes are slowly removed because individuals that have them are less likely to survive amp reproduce Natural selection is not a force like gravity but the result of a natural process due to variations SUMMARY Because of competition for resources not all individuals can survive Individuals vary from each other amp the ones with features better suited to their environment are the ones that survive amp reproduce They pass those features on to their offspring This continues over generations causing the features that allow individuals to survive to become more common in the population The features that make an individual more fit depend on the environment As different populations adapt to their different environments new species eventually evolve MODULE 1 LECTURE 3 INTRODUCTION This lecture Provides more examples of natural selection Explains two different types of natural selection directional amp stabilizing Discusses what was missing from Darwin s theory MAIN IDEAS Kettlewell Predation Experiments 1950s Studied a population of peppered moths in which some were light in color amp some were dark Initially lightercolored moths were camou aged with trees Birds ate more of the darkercolored moths because they were not camou aged leading to a higher concentration of lightercolored moths During the Industrial Revolution trees darkened due to pollution from factories Darkercolored moths were now camou aged amp birds began to prey on lightercolored moths leading to a higher concentration of darkercolored moths in the population Controversy Was the way the moths were observed sitting on the trees actually the position in which they rested amp were seen amp eaten If bird vision is different from human vision the same color of moths that appear camou aged to us don t necessarily appear camou aged to them Grants Galapagos Finch Study Study of finches in the Galapagos Islands over several years A severe drought occurred during the study Plants produced fewer of the seeds that the finches eat Beak size increased Why The finches preferred smaller seeds so these were eaten first leaving only the larger seeds Birds with larger beaks were the ones able to eat the larger seeds amp therefore survived amp reproduced causing an increase in concentration of birds with larger beaks in the population over time Study documented that parents with larger beaks produced offspring with larger beaks amp that the population s average beak size increased measurably over two years Directional selection One extreme is favored over the other causing a shift over time towards that extreme Stabilizing selection The average value has the highest fitness while both extremes have lower fitness Can lead to stasis in which a species seems to have stopped changing KEY POINTS Natural selection does not create variation It works because of variation Individuals do not change their features The relative frequency of certain features in a population changes over time Natural selection amp its applications to humans Domestication of plants We select for traits that taste good resist insects survive drought etc This can completely change a plant over time such as corn Modern health amp medicine Fear that antibiotics antibacterial soap etc select for the stronger bacteria that are able to resist them This is why you always need to take the full course of antibiotics Public health Humans have evolved to crave fat amp salt because you need them amp they used to be rare so the humans who ate them were the ones that survived amp reproduced They are no longer rare but we still crave them because we evolved to Microevolution vs macroevolution Microevolution or evolution within a species is easily observable amp widely accepted Macroevolution or the origin of new species is hard to observe because it takes so long Because of this opponents argue that it has never been documented Microevolution and macroevolution are caused by the same mechanisms amp are essentially the same thing only differing by the amount of time it takes for them to occur CONCLUSION What was missing from Darwin s theory Didn t know how the variations between individuals of a species were generated because no one understood genetics at the time Didn t know how traits were inherited Believed in blending inheritancequot in which the offspring is an average of the two parents Ex Black moth white moth all babies are grey
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