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BSC 2011 Learning Objectives, Unit 1: EvolutionChapter 22: Descent with modification, a Darwinian view of life1. Identify Darwin and Wallace’s contribution to the theory of evolution, and place it in the context of the ideas proposed previouslyDarwin proposed:o Adaptations: the characteristics that allow organisms to survive in determined environmentso Traits can be accumulated throughout time and manifest at some point o Natural selection: the theory that states that the organisms with better adaptations to the environment, are a better matched to it, have higher chances of survival in said environment than those who do noto Studied in the Galapagos Islands o Thought that present organisms had a common ancestor o INDIVIDUALS do NOT evolve… populations DO oObservation #1: the traits inherited are not always the same (what later was known as dominant and recessive)oObservation #2: the species have the ability to produce more organisms that the environment can support, therefore some of these offspring may die because not enough resources.o Inference #1: Organisms with specific traits that survive in their environment are more likely to reproduce and leave offspringo Inference #2: As the organisms with the traits not favorable for the environment die, they take with them those traits, making that all the favorable traits remind more viable.Wallace proposed:o Studied species on South Pacific Islands, Malay Archipelago o Proposed a natural selection theory very similar to Darwin o Push that Darwin needed to write his book on development of species2. Explain five lines of evidence that support the theory of evolution: fossil record, biogeography, convergent evolution, direct observations (natural and artificial selection) and homologiesFossil Record:o Used to compare the species from the past and the present and see evidence of how they have evolved o Compare physical characteristics between species o Reminds of DNA in the bones and fossils can be used to compare species o … StructureBiogeography:o Study of how species are placed/distributed throughout the planet (geographically)o Pangaea: when all the landmasses were connected about 250 million years ago. o Help to understand where and when species migrated by using fossils found in different geographic regionso Endemic: species that exist in just one place, therefore probably original from there.All the information in this document was outlined from the “Capmbell Biology” 10th edition book by Jane B. Reece, Lisa A. Urry,Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, and Robert B. Jackson; Pearson Publisher
o Research have found that species in islands are closer related to species of nearby islands or the closest landmarks, and probably not so much to further away landsConvergent evolution:o When species develop physically similar because they adapt to similar environments therefore they have similar features even if they are genetically very differento Analogous structures: similar physical appearance and functionDirect observations:o Natural selection: there must exist variation in the population already in order for nature select the “better genes” natural selection does NOT “create” new geneso Bacteria resistance to antibiotics come about because the few bacteria that had genes able to resist the antibiotics survived and reproducedHomologies:o Homologous structures: structures that are not necessarily similar in shape or with the same function, however they share a common ancestoro Evolutionary tree: diagram that reflects the genetic similarities between organisms o Vestigial structures: features in organisms that are no longer used in current species (became obsolete) however they served a purpose to the past ancestoro Molecular homology is the similarities in DNA and since all living organisms use genetic sequence the theory is that all of them have descent from an ancestor that used it as well.3. Describe the mechanism of natural selectionSome species survive better than other thanks to their traits“Over time, natural selection can increase that match between organisms and their environment”In case the environment changes natural selection occurs again and some new species may ariseIndividuals DO NOT evolve, populations DONatural selection can only occur if there is genetic variation4. Define the following terms: descent with modification, homology, homologous structure, analogous structure, convergent evolution, fossil, vestigial structure, evolutionary tree, biogeography, artificial selection, adaptationDescent with Modificationso Darwin argued that all current organisms descended from another one thatlived many years before that oneo The current species grouped into different locations, hence the adaptations they have, which can make them different from other organisms with the sameo Said adaptations can give these organisms advantages over others which allow them to survive betterHomology: “Similarity resulting from common ancestry” (p. 473)All the information in this document was outlined from the “Capmbell Biology” 10th edition book by Jane B. Reece, Lisa A. Urry,Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, and Robert B. Jackson; Pearson Publisher
Homologous Structures: “represent variations on a structural theme that was present in their common ancestor” (p. 473)Analogous Structures: “Share similar function, but not common ancestry” (p. 475)Convergent evolution: “The independent evolution of similar features in different lineages” (p. 475)Fossil: “A preserved remnant or impression of an organism that lived in the past” (p. G14)Vestigial structure: “a feature of an organism that is historical remnant of a structure that served a function in the organism’s ancestors” (p. G36)Evolutionary tree: “a branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms” (p. G 13)Biogeography: “the scientific study of the past and present geographic distributions of species” (p. G4)Artificial selection: “the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits” (p. G3)Adaptation: “Inherited characteristics of an organism that enhances its survival and reproduction in a specific environment” (p. G1)Chapter 23: Evolution of populations1. Explain how the smallest unit of evolution is a populationPopulation is the one that evolves because the mutations that happen in individuals are usually very small and unnoticeable/nonharmfulThese mutations accumulate from individual to individual until eventually something DOES change due to these accumulations and a new “species” arise.The individuals themselves stay the same and when they mate , their OFFSPRING are the ones that can be changed2. Discuss why variation in populations is common and is necessary for natural selectionNatural selections, as it says, is a SELECTION, and in order to select there the trait had to be there to begin withNOTICE natural selection shrinks the gene pool/gene variation, because it goes from a large quantity of genes and pick specific ones because X and Y and the ones that are not in this selection disappear, which leads to extinction3. Use the HardyWeinberg equilibrium to answer questions about allele frequency, genotype frequency, and evolution in a populationp + q = 1“p” and “q” by themselves are the frequency of the allele “A” and “a” genotype separately 9not the combination of the 2), NOT the phenotype4. Describe the five conditions required for HardyWeinberg equilibrium and recognize that allAll the information in this document was outlined from the “Capmbell Biology” 10th edition book by Jane B. Reece, Lisa A. Urry,Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, and Robert B. Jackson; Pearson Publisher
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