GE146 Section III Full Notes

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Boston College
Earth & Environmental Sciences
EESC 1146

GE146SectionIII02272014Darwinian EvolutionSpecies ConceptsNatural SelectionHomologyAnalogyCharacter PolarityOrigin of Species different kinds of speciesNatural Selection a process revealed in the pattern of relationships between and among speciesPatternphylogenySpecies Concepts many different definitions of speciesNatural Selection revealed process pattern of relationships of speciesphylogenyGeneration of VariationCreates variations of speciesMutations repaired or lethalHybridization two different species that come together and create viable offspringSymbiosis joint geno in a third type of organismNatural SelectionThe variation within the individual bestows the ability to survive remain neutral or dieFitnessreproductive survivalHomology you can see the relationship of characters between different organismsspeciesBuilds the pattern of phylogenySpecies ConceptsBiological species groups of populations of organisms potentially capable of interbreeding nature which are distinct from other such groupsPaleontological Species groups of organisms with similar morphology with their own evolutionary role and tendenciesWanted an addition of timeMorphological species groups of organisms that look alikeUsed to define speciesTypological species groups of organisms that look similar to a selected individual the typeProvides a physical example of the grouping ie humansObamaBefore Darwins Time 2 competing notions of speciesFixity of the species God creating species as being fixed or permanent immutable Would perpetuate in timeMorphologyLamarckTransmutationsall species were varying all the time no consistency Morphology was always changingDarwin took these 2 notions and came to compromiseNo permanence of species can evolve and also remain the sameClinal SpeciesFrogs can interbreed locallyBring the same frogs together from different regions cant interbreed ie NJ FLCan interbreed from one pop to anotherA type of allopatric speciation in which a geographic barrier falls across a cline cutting a species into two segments which are thus already somewhat different and which can continue to diverge in their new isolationAllopatric Speciation1Generation of variation2Variance of biogeographyoccurs when biological populations of the same species become isolated from each other to an extent that prevents or interferes with genetic interchange This can be the result of population dispersal leading to emigration or by geographical changes such as mountain formation island formation agricultural The vicariant pops then undergo genotypic or phenotypic divergence as a they become subjected to different selective pressures b they independently undergo genetic drift and c different mutations arise in the populations gene pools1The separate populations over time may evolve distinctly different characteristics If the geographical barriers are later removed members of the two populations may be unable to successfully mate with each other at which point the genetically isolated groups have emerged as different speciesDarwin studying the finches on the Galapagos
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