Quiz 5 Study Guide
Quiz 5 Study Guide Bios 207
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This 3 page Study Guide was uploaded by Cara Cahalan on Thursday April 7, 2016. The Study Guide belongs to Bios 207 at University of Nebraska Lincoln taught by in Spring 2016. Since its upload, it has received 6 views. For similar materials see Ecology and Evolution in Biology at University of Nebraska Lincoln.
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Date Created: 04/07/16
Quiz 5 Notes: 3/28: Species Diversity Lecture: 3 filters that narrow: regional species pool local community, determine the diversity in any particular area o Dispersal or immigration must reach somewhere to inhabit o Abiotic factors all characteristics influence niches o Species interaction cannot exist with a dominant competitor FF: as 1 species approaches K, the other cannot complete and their abundance decreases K 2 o Species 2 is excluded by spices 1. This means th21 α K 1 o Why does species 2 persist longer in the bottom figure? Disturbance slows competitive exclusion, α’s, K’s, and growth rates change (/+) with disturbance FF: What is happening at A? o Competitive exclusion lowers diversity B? Disturbance lowers diversity C? Disturbance limits competitive exclusion and competitive exclusion is reduced Intermediate disturbance hypothesis: Niches allow a lot of species to come in and occupy certain environments greater species diversification C Coexistence: how do we get species? B A 3/30: Speciation I Readings: Phylogenetic species concept: species are smallest possible group whose members all come from one common ancestor who all possess defining or derived characteristics distinguishable from other groups Biological species concept species are groups of interbreeding natural populations that are reproductively isolated from one another BDM incompatibilities genetic incompatibilities in hybrid offspring arising from epistatic interactions between two or more loci Reinforcement increase of reproductive isolation between pop through selection against hybrids Lecture: Speciation involves barriers to reproduction (gene flow) o Once barrier to reproduction emerges evolution can proceed separately and lineages differentiate o Original species diverges into two groups of populations that behave as independent evolutionary lineages Species group of individuals that is reproductively isolated, evolving independently from other populations, and morphologically and genetically distinct General lineage species concept: species are metapopulations that exchange allele frequently enough to comprise the same gene pool o Metapopulations group of spatially separated populations of the same species that interact at some level Reproductive isolating barriers: FF: o What was the barrier to reproduction in flies? Timing (niches) Ecological speciation ADD DEFINITION Allopatry populations are in separate, nonoverlapping geographic areas 4/1: Speciation II Readings: Allopolyploidy polyploidy (more than two paired chromosomes) resulting from interspecific hybridization o “instant speciation” Lecture: Fastest recorded speciation rate in arthropods: ~4 species/million years Song differences reinforce separation originally driven by ecology barrier reinforcement Reinforcement vs. hybrid speciation: o Reinforcement trait changes that make hybridization harder o Hybrid speciation trait changes in hybrids that make them a separate lineage (Heliconius butterflies) H. heurippa intermediate form that prefers to mate with itself and patterns can be produced with crosses (1 generation divergence of lineages) 4/4: Macroevolution Readings: Macroevolution evolution occurring above the species level (origination, diversification, and extinction of species over long periods of time) Microevolution evolution occurring within populations (adaptive/neutral changes in allele freq. over time) Biogeography study of distribution of species Vicariance formation of geographic barriers to dispersal and gene flow separation of once continuously distributed populations o Splitting of land mass: most closely related species should come from most recently separated land mass Diversity equation: D1 + originations + immigrations – extinctions – emigrations2= D o D diversity (total number of species) studying macroevolution o On global scale: 1 (diversity) + originations – extinction2 = D (new diversity) o Changes in diversity over time can be studied by looking at interplay between origination and extinction Turnover total number of originations and extinctions in given time o α rate at which new species evolve (origination rate) o Ω rate at which species become extinct (extinction rate) Adaptive radiations evolutionary lineages that have undergone rapid diversification o May occur when clades evolve to occupy ecological niches in the absence of competition o Absence of established competitors for the resources in an environment Lecture: Phenology timing of growth and reproduction o Seeds don’t plant at any time, right timing improves fitness o Timing in nature is at least partly heritable and genetic evolution o Birds often match timing offspring production to peaks in food availability Microevolution is evolution occurring within populations and macroevolution refers to patterns at or above the species level. FF 1: vicariance generated barriers to dispersal between Australia and (Asia, Antarctica, and Africa) o Plate tectonics influences the evolution of marsupials altering dispersal routes, interspecific competition, vicariance, and climate Diverse taxa have higher origination rate than extinction rate (α > Ω) FF 2: rapid divergence of species from a common ancestors that fills multiple niches is adaptive radiation Taxonomic diversity positively correlates with mean temperature Multiple adaptive radiations in Hawaii overlap but are not exactly simultaneous o Species diversity is greatest in the tropics (α > Ω) Fossil record documents transitions 4/6: Radiations and Extinctions Readings: Background extinctions normal rate of extinction for a taxon or biota Mass extinctions statistically significant departure from background extinction rates that result in a substantial loss of taxonomic diversity o Either increase in extinction rates or decrease in origination rates (or both) Big 5 mass extinctions caused by: o Physical factors: sealevel regression or transgression, climate change th o Extraterrestrial causes: solar flares, supernovas, impact of asteroids and comets 6 mass extinction humans could be cause? Haven’t reached critical level yet Lecture: Open niches left by the extinction of dinosaurs are filled by new species adaptive radiation th KT extinction: 5 mass extinction, loss of large clade allowed mammals to radiate o May have been caused by asteroid impact Humans may be driving the 6 mass extinction, drives species towards extinction o Habitat loss contributes to extinction Increasing CO2 leads to warming temperatures and acidifies the ocean o Taxonomic diversity is positively correlated with mean temperature What’s on the quiz? Reproductive barriers o Premating, prezygotic, and postzygotic Macroevolution o Adaptive radiation o Extinction patterns Speciation o Vicariance Species diversity o Intermediate disturbance hypothesis
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