Bio Exam 1 Study Guide
Bio Exam 1 Study Guide BIOLOGY 1114 - 0010
Popular in Biological Sciences: Form, Function, Diversity, and Ecology
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This 14 page Study Guide was uploaded by Sean Bhatnagar on Sunday September 27, 2015. The Study Guide belongs to BIOLOGY 1114 - 0010 at Ohio State University taught by Staff in Fall 2015. Since its upload, it has received 51 views. For similar materials see Biological Sciences: Form, Function, Diversity, and Ecology in Biology at Ohio State University.
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Date Created: 09/27/15
Biology 1114 Exam 1 All notes 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 0 Variations exist in the population before any selection occurs 0 Populations as a whole evolve through evolution NOT individuals 0 Natural selection is NOT random 0 Evolutionary changes occurhappen across generations not within a generation What things are not biological evolution Individual development ecosystem change cultural evolution Why study evolution 0 To understand the diversity of Life I Conservation Biology the aim of protecting species their habitats and ecosystems from excessive rates of extinction and the erosion of biotic interactions 0 Fisheries management Ex Crops and plants and their study 0 Agriculture Ex Pesticide Resistance 0 Forensics and Paternity analysis 0 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 0 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 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 Differences among organisms have accumulated in small increments over a long time Outgrowth of his uniformitarianist perspective 3 Population differentiation Changes in species re ect changes in the proportion of individuals in a population bearing certain hereditary traits Changes in species take place at the level of individualswithin population Talking here about variation among individuals Not a sudden origin of new species or transformation of individuals VARIATION NOT TRANSFORMATION 4 Natural selection Population differentiation caused by differential reproductive success of individuals bearing particular traits Individuals that have more success are those better able to use resources in a particular habitat 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 Darwin s Ideas summarized 0 There is a natural variation in a population 0 There are more offspring that are produced that can survive 0 Organisms with favorable traitsvariations will survive and leave more offspring 0 Accumulation of differences over a long period of time will lead to adaptive radiation There are 4 Postulates of natural selection p x Variation Some individuals in a population have variations of genes 2 Inheritance Some of these variations can be passed on to offspring 3 Differential survival Every generation there are more offspring produced than can survive all won t survive 4 Extinction The survival and reproduction of individuals isn t random They just don t have favorable variation Variation The material for evolution by natural selection Know this sentence and each component Without variation in individuals there can t be evolution Discrete Variation Multiple forms within a species also called polymorphism Continuous variation Exactly how it sounds There are noticeable variation within different generations over time Variation can be Genetic or Environmental Genetic Darwin wasn t goodeducated with heredity Evidence favored Weismann s germplasm theory Weismann s germplasm theory was germs vs soma Gregor ne Johann Mendel 18221884 0 Born in Hyncice Moravia Austria and was educated at Institute of Philosophy Olomuc Czech Republic 0 He joined the Augustine Order of St Thomas at 21 0 In uenced Darwin s work on plant and animal domestication Mendel s Contributions to heredity were Dominance Segregation and Independent Assortment He also gave a theory of heredity 0 Genes are preserved during development 0 Genes are passed to offspring unaltered 0 Organisms can be carriers of genes 0 Phenotypes can be intermediate but genes don t fuse together or blend His experiments included peas and owers Mendel s Law of Dominance 1865 Henceforth in this paper those characters which are transmitted entire or almost unchanged in the hybridization and therefore in themselves constitute the characters of the hybrid are termed the dominant and those which become latent ie hidden in the process recessive Or the characteristics that are transmitted entirely or are hybridized through are dominant and the characteristics that are hiddenuneXpressed are recessive Mendel s Law of Segregation 4 Parts 1 The inheritance of traits is determined by the genes that are passes on by parents Alternative versions of genes account for the variation in inherited individuals 2 An individual inherits one allele from each parent 3 The two members of a gene pair separate randomly and equally into gametes These gametes then form randomly and equally to form the next generation s gene pair 4 Individuals can have traits and are able to pass them on even if they don t show it Independent Assortment Alleles come individually Dominant alleles can pair with other dominant pair and recessive alleles The molecular basis of Mendelian genetics Simple dominance When 2 alleles are present in an individual one factor is dominant and its trait is preferentially expressed Reginald C Punnett 18751967 0 Considered father of genetics 0 Combined Mendel s laws with statistics 0 Experimented with peas 0 Created Punnett square William Bateson 1861 1926 0 Translated mendels work into English 0 Coined terms such as genetics allelomorphs alleles heterozygote and homozygoe 0 Established the Cambridge School of Genetics 0 Collaborated with Punnet on genetic experiments Know how to do monohybrid and dihybrid cross Generating genetic variation Mutation the ultimate source of all heritable variation 0 Point mutation after single nucleotide Know Transversion vs Translation Sources of genetic variation Mutation is the ultimate source of all heritable variation 0 Unequal crossingover alters larger sections of DNA Recombination shuf es existing variation into new combinations 0 Create new combinations that lead to greater levels of phenotypic variation Random or Directional Mutation and recombination are random 0 Changes are usually nonadaptive or even maladaptive although sometimes they can be harmful O Mutation and recombination can be nonrandom at the molecular and chromosomal level Ex certain nucleotides substitutions are more than likely than others 0 Mutations act on existing genes modifying or generating new alleles 0 Their impact can be large or small May cause early death or go unnoticed silent mutations CoDominance both alleles are expressed and the heterozygote expresses a third phenotype They are both present Incomplete Dominance the alleles are blended together Like the pink ower Pleiotrophy single gene impacts two or more traits Epistasis one gene interferes with the expression of another gene What is the difference Pleiotrophy is one gene with multiple phenotypic effects where as epistasis is two genes contribute to one phenotype Polygenic Traits Several genes may make products that contribute to phenotype Phenotype is determined by interaction of multiple genes Ex Eye color 4 genes determine eye color Nongenetic factors can complicate gene expression Genotype is expressed in the context of its bearer Environmental Effects Temperature within nest determines sex Maternal Effects Special case of environmental Environmental features that can be attributed to mother environmental of wombegg Amount of yolk in egg Post birth maternal care Variation due only to environmental effects is not a factor in evolution There are experiments to know if a phenotype is environmentally or genetically determine Controlled crosses common garden experiments and cross fostering Controlled crosses Determine whether phenotype is inherited according to Mendelian laws Common garden experiments Raised offspring under identical conditions Run several gardens to test effect of particular variables Cross fostering Common gardens for animals Have offspring reared by parents other than their own Break up litters at birth randomely redistribute young among family groups Phenotype Genotype Environment Review and Know Darwin s Postulates of Natural Selection 0 Variation 0 Inheritance 0 Differential Survival 0 Extinction Hardy Weinberg only works under specific conditions 0 All offspring have an equal chance of survival and reproduction O Equals no selection 0 Large population size 0 Random events will have a large impact on small populations The HardyWeinberg requirements are integral to evolution 0 All offspring have an equal chance of survival and reproduction 0 Natural selection 0 Large Population size 0 Genetic drift 0 No new Alleles O Mutation and migration 0 Random Mating 0 Sexual selection 0 Geographic variations and clines Selection is the NONRANDOM differential survival and reproduction of particular phenotypes 0 2nd component of evolution by natural seletion 0 1st is the origin of genetic variation HA2 VgV p 0 Strength of selection depends on the heritability hquot2 and on the degree of difference in fitness among phenotypes Fitness Defined for a genotype and pertains to particular situations Fitness is the reproductive output R of all organisms bearing the genotype Fitness doesn t mean anything related to exercise for species Reproductive output is the individual s effort of all organisms bearing that genotype How many eggs are produced Based on Genotype and Environment What is the probability of fertilization Genotype and environment The interplay of the variables determines R fitness EX High number of propagules incurs a high energy investment for women so each typically gets less yolk or car They reproduce a lot and so they have certain amounts of energy per egg which comes from investment of women And Low investment per propagules may decrease survival rate Mom gives less nutrients to each egg Variables 0 Number of individuals having offspring 0 Number of reproductive propagules Number of reproducers X Number of eggs upper limit on reproductive output per cycle 0 Number of cycles per year and number of cycles per female lifespan both in uence population growth rate Number of cycles per year 0 Annual seasonal lunar cycles Age of sexual maturity Lifespan and Lifetime reproductive profile 0 Fertility and fecundity change over time Not just birth but Death 0 Reproductive senescence before death 0 This means they know when they will die and this can trigger reproductive output and some will stop reproducing after a certain age 0 Survival rate of propagules Factors that contribute to fitness and population growth 0 Number of reproductive females 0 Number of offspring per cycle 0 Number cycles per unit time 0 Number cycles per female life 0 Death rate of reproductive individual 0 Survival rate of offspring In uences on Population size 0 Density Independent factors Effect is the same regardless of population size or density 0 Environmental phenomena Drought long winters etc 0 Increase mortality across the whole population thus decreasing amount of reproducing females 0 Density dependent factors Effect is modulated depending on population size or density 0 Supply food or other resources Resources notlimited for smaller populations but may become limiting if population increases 0 Disease may spread more effectively and pathogenspredators may increase in numbers in response to increase in prey density 0 Dependent factors integrate resources availability and competition with population growth FITNESS 0 Fitness is determined by the reproductive output R for each genotype This is important don t assume fitness is something else 0 The average R of the entire population all genotypes determine the populations overall average fitness Components of fitness are 0 Viability Probability that individual bearing genotype will survive 0 Fecundity Number of gametes per individual 0 Mating Success Number and quality of mates 0 Gamete Viability Alleles impact the longevity quality of eggsperm 0 Fertilization success Alleles impact the probability that fertilization will take place Fitness is the sum of all fitness components Fitness is also relative We don t know what the bestfittest can be because we can t tell whether a genotype or phenotype is optimal the best We can which is BETTER but not the best Also conditions can change so we do not easily know which would be the best Difference in fitness create trouble in the successful transmission of alleles If certain elements of an environment aren t fit for an individual it can interfere with the successful transmission of the alleles Surviving probabilities are different from reproductive probabilities Selection Selection is considered directional if individuals at one extreme of range of phenotypes are fittest Selection is considered disruptive if 2 or more discontinuous phenotypes are fittest Selection is considered stabilizing if intermediate phenotype is fittest Selection is positive if it favors the phenotype genotype Selection is negative if it eliminates a phenotype genotype Frequency dependent selection is when selection and its impact differ depending on the frequency of certain genopheno types Frequency independent selection is when the selection doesn t have anything to do with the frequency of alleles in the population Endemic species species that are only found in certain places As long as there are changes in allele frequencies due to survival then there is evolution Evolution can occur within a few field seasons Darwin himself was surprised that Evolution can be observed within a lifetime Evolution can occur at very small scales Through the Grants measurements and research they found that 5mm was enough to make a difference between survival and death during a drought year Natural selection can occur without heritability but Evolution by natural selection cannot It s not too hard of a concept just read it over Pretty simple Heritablity is the genetic component Evolution doesn t equal Natural Selection Natural Selection is one mechanism of evolution Others are genetic drift and Mutation They don t rely on each other
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