Exam outline:Exam ReviewKey TermsOverview of UnitBIO SCI 150 1st EditionExam # 3 Study Guide Lectures: 13 - 18 Exam outline:Chapters 15, 16, 17 – Mainly Lecture NotesReview outlines – Key40 multiple choice questionsExam ReviewKey TermsFossil Record - preserved remains of organismsSystematics - the science of reconstructing phylogenyTaxonomy - ID and classificationPhylogeny - evolutionary historyHox genes - Trigger the development of antennae, wings, legsSpeciation: the origin of new speciesIsolation: created by reductions in gene flow.Divergence: created when mutation, genetic drift, and selection act on populationsSpecies: distinct types of organisms that represent evolutionarily independent groups.The Biological Species Concept: Individuals of different species cannot interbreed, and their populations are considered reproductively isolatedThe Phylogenetic Species Concept: the smallest set of organisms that share an ancestor and can be distinguished from other such sets.Phylogeny: the evolutionary history of a group of organisms Phylogenetic tree: a branching diagram that depicts the evolutionary relationships between organismsMonophyletic group (one- tribe): An ancestral species and all of its descendants (=branch, lineage or clade)Allopatric: Geographic barrier blocks gene flowSympatric: Intrinsic barrier blocks gene flowColonization events: a species spreads to new areas Vicariance event: a physical barrier separates a populationAdaptive radiation: evolution of many species from a common ancestorSecondary Contact: Mechanisms that can prevent gene flow when reproductively isolated species come back in contact with each other following isolation and divergencePrezygotic mechanisms make it very unlikely that interbreeding will even take placePostzygotic mechanisms cause hybrids to become sterile or to fail to develop properly.Polyploidy, a type of mutation, where more than 2n chromosomes are presentTetraploid (4n chromosome number)Natural Selection - Differential survival and reproduction of genotypesDirectional selection - favors one extreme or the otherStabilizing selection - favors intermediate individuals Disruptive/Diversifying selection - favors different genotypes that produce different phenotypesBalancing selection - maintains genetic variation Sexual dimorphism - difference in appearance in males and femalesBiodiversity – two kinds of approaches…- Ecology (the how)o How organisms interact with their environmento Proximate (Immediate) causes of distribution and abundance - Evolution (the why)o How organisms have changed over time o Long-termBiogeography - Distribution of speciesHomology - similarities due to sharing a common ancestorDevelopmental homology – “something that can be viewed in the fossils of certain animals that point to and evolutionary change in their current incarnations”Genetic homology – similar genes control similar developmentLaw of succession - living and fossil species in the same area are similarVestigial traits – left over traitsConvergence - similarities due to evolution in similar environmentsArtificial selection = Natural selection (just caused by man)Evolutionary Processes - a change in allele (gene) frequencies over timeThe Hardy-Weinberg Model - The model predicts the allele and genotype frequencies when there is no evolutionMigration - the movement of alleles between populations, aka gene flowGenetic Drift - This is any change in the allele frequencies in a population that is due to random chance. LECTURE QUESTIONS When will the biological species concept NOT work?- When species are sympatric- When species are nearly indistinguishable in morphology- When species are reproductively isolated- When species are exclusively asexualNatural selection…- Is a random process- Acts on populations to benefit the species- Act on individuals, and leads to evolution of populations- Mean s that only the strong surviveHomologous traits are similar because…- They result from convergent evolution- They are derived from different ancestors- They are derived from a common ancestor- Their appearance, structure or development is similarWhen they were first introduced insecticides were highly effective killing mosquitoes. Today over 50 years later, a smaller percentage of individuals are killed.Why do you think this occurs?- Mosquitoes needed to be more resistant, so adults passed on increased resistance to their offspring over many generations- Insecticides have caused more mutations and these have increased the level of resistance- Mosquitoes that are resistant produce more offspring that inherit the resistance- Insecticides have improved, so mosquitoes are just keeping upGiven H-W equilibrium, and the frequency of the r allele is 0.3, what proportion of the population is heterozygous for this allele?- 0.03- 0.09- 0.42- 0.30Overview of Unit- Evolution is “descent with modification”o Both a Pattern  Organisms are related by descent from common ancestors Organisms have changed over timeo and a Process  Natural Selection- Evolution is measured as change in allele frequencies in a population.- Four mechanisms change allele frequencies in populations: Mutation, Migration, Genetic drift & Natural selection- Only Natural Selection causes adaptive evolutionary change - Adaptation: o 1) traits that increase fitness, oro 2) the process of evolutionary change- Sexual Selectiono Based on differential reproductive success males with the “best” traits produce the most youngo Explains traits that reduce survival- Speciation is the outcome of isolation and divergence KEY- Species are distinct types of organisms that represent evolutionarily independent groups.- Lack of gene flow makes a species independent. - Modes of Speciationo Allopatric - geographic barrier blocks gene flowo Sympatric - intrinsic barrier blocks gene flowTools for Studying The History of Life- Fossil Record - preserved remains of organisms- Systematics - the science of reconstructing phylogeny- Goals:o Taxonomy - ID and classificationo Phylogeny - evolutionary