Week 1 Notes
Week 1 Notes BIOLOGY 1114 - 0010
Popular in Biological Sciences: Form, Function, Diversity, and Ecology
Popular in Biology
This 7 page Class Notes was uploaded by Sean Bhatnagar on Saturday August 29, 2015. The Class Notes belongs to BIOLOGY 1114 - 0010 at Ohio State University taught by Staff in Fall 2015. Since its upload, it has received 74 views. For similar materials see Biological Sciences: Form, Function, Diversity, and Ecology in Biology at Ohio State University.
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Date Created: 08/29/15
Biology 1114 Notes Week 1 Evolution the change in allele frequencies in a population over time There are a lot of misunderstandings and sometimes the word is misused Examples to further understand what evolution is Variations exist in the population before any selection occurs Populations as a whole evolve through evolution NOT individuals Natural selection is NOT random Evolutionary changes occurhappen across generations not within a generation What things are not biological evolution Individual development ecosystem change cultural evolution Why study evolution To understand the diversity of Life Conservation Biology the aim of protecting species their habitats and ecosystems from excessive rates of extinction and the erosion of biotic interactions Fisheries management Ex Crops and plants and their study Agriculture Ex Pesticide Resistance Forensics and Paternity analysis Medicine Ex Evolutionary medicine and advances Huntington s Chorea Screening for diseases and Antibiotic resistance 0 Bacteria I Short Generation time I Lots of variation I Easily pickup pieces of DNA I Allow Bacteria populations to evolve quickly Historv of Evolution Evolution before Darwin Evolutionary thinkers existed but lacked mechanisms to drive evolution Dominant ideas before Darwin Essentialism was The physical world and its life forms are fixed 0 All members of a class share unchanging properties that define the class 0 Attributed to Greek philosopher Aristotle 3 84322 BC Scala Naturae 0 The great chain of being 0 Life arranged hierarchically culminating in divinity Carlos Linnaeus Swedish 17071778 Carl von Linneaus was a botanist and known to be the father of modern taxonomy 0 Systema Naturae 1735 binomial nomenclature 0 Hierachical taxonomy embodied Scala Naturae Scala Naturae and Hierachical taxonomy is still used today but re ects evolutionary relationship Laclerc aka Buffon George Louis Leclerc 17071788 was a French scientist who recognized the difference between related species living in different parts of the world re ect the different environments they inhabit Also after migration organisms must somehow change to suit their new environment Lamark J eanB apiste Lamarck 17441829 0 Philospohie Zoologique 1809 0 First explicit scientific treatment of evolution Transformism 0 Lineages persist forever but change in form 0 Vague mechanism of internal force 0 No extinction or branching of lineages Inheritance of acquired characters 0 Individuals change during development 0 If changes are beneficial parents transmit these acquired characters of their offspring 0 Famous discussion of giraffes neck Cuvier Georges Cuvier French 17691832 was a Paleontologist and comparative anatomist who was a strong critic of Lamarck s ideas He favored essentialism 0 Disputed Lamarck s claim that forms change gradually over time 0 Correlation of parts organisms are so integrated in form and function that any changes would lead to death irreducible complexity On Extinction 0 First to firmly establish extinction as fact 0 Rigorously reconstructed and classified fossils of mastodons and many other extinct organisms 0 Attributed extinction to discrete catastrophic events The Geologists Hutton and Lyell James Hutton Scottish 17261797 0 Gradualism Earth s physical features gradually changed due to slow geological processes Charles Lyell British 17971875 0 Uniformitarianism Historical changes result from uniform geological processes that still occur today erosion sedimentation volcanism 0 Supplanted geological catastrophism Changing views of earth s history 0 Earth has had a complex history during which it has changed significantly in terms of its geology topography and inhabitants 0 The complexity of the Earth s history can be explained in terms of the processes that are observed today erosion volcanism ect Implications Earth is very old and is always slowly changing and Past can inform the present and vice versa Review setting the stage for Darwin Essentialism is dominant 0 Most people including most biologists still thought that species do not change in party because of in uential essentials like Cuvier or Linnaeus No satisfactory theory for biological diversity 0 Those who favored evolution Lamarck had incorrect views of the process Transformism and the mechanism inheritance of acquired characters Extinction and Branching 0 Cuvier demonstrates that extinction happens and even those who favor evolution don t think that the species can split Uniformitarianism is promoted 0 Geologists Huffon and Lyell argue that the Earth is old and constantly changing not static and unchanging as thought by essentialists 0 Could species also be gradually changing with their environment Darwin Darwin proposed the mechanism for evolution which he called Natural selection He defined and said the outcome of evolution comes from descent with modification What led Darwin s ideas about evolution 0 Modern species in some cases resemble fossils 0 Modern domesticated animals can be made to vary through intentional selection artificial selection 0 The creature in archipelagos vary from island from island 0 Organisms may have very complex modifications that are necessary for their survival General observations about domesticated varieties 0 Unlike wild species most varieties are freely interfertile 0 Closely related varieties show more pronounced morphological differences than closely related wild species Artificial selection new varieties arise by preferentially breeding individuals showing specific desirable traits 0 Traits arise as random sports that are then selectively bred 0 This process occurs over many generations not in a single step Improvement of breeds is a continual process resulting in the accumulation of fairly significant modifications in a relatively short period of time Darwin s big idea wild species also undergo selection Rather than accumulating large modifications over several generations natural species accumulate many tiny changes over a VERY long period of time Thomas Robert Malthus 17661894 Premise Left unchecked human reproduction rates will rapidly outpace resource production leading ultimately to crime disease war and vice these being natural checks on population growth Reproductive Consequences Favorable beak morphologies are passed on to offspring Very small morphological changes accumulate over a long period of time leading to eventual morphological divergence of populations Widely differing morphologies gradually become reproductively incompatible Seeing this gradation and diversity of structure in one small intimately related group of birds one might really fancy that from an original paucity of birds in this archipelago one species had been taken and modified for different ends Darwin 1845 Darwin s four postulates of natural selection 1 Variation Individuals within species are variable 2 Inheritance Some of these variations are passed on to offspring 3 Differential survival In every generation more offspring are produced than can survive 4 Extinction The survival and reproduction of individuals is not random Individuals who survive and reproduce are those with the most favorable variation Darwin proposes more than natural selection 1 Common descent 0 All living things part of a community of descent 0 Organisms that are more closely related have a more recent common ancestor more similar than those that are more distantly related 2 Gradualness of change over time 0 Differences among organisms have accumulated in small increments over a long time 0 Outgrowth of his uniformitarianist perspective 3 Population differentiation 0 Changes in species re ect changes in the proportion of individuals in a population bearing certain hereditary traits 0 Changes in species take place at the level of individualswithin population 0 Talking here about variation among individuals 0 Not a sudden origin of new species or transformation of individuals 0 VARIATION NOT TRANSFORMATION 4 Natural selection 0 Population differentiation caused by differential reproductive success of individuals bearing particular traits 0 Individuals that have more success are those better able to use resources in a particular habitat 0 Same principles independently derived by Alfred Wallace during his work in Malaysia Alfred Russell Wallace OProfessional curiosity collector Wrote a paper on natural selection in 1858 and sent it to Darwin 0A year later Darwin published Origin of the Species
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