i) New toolsii) Rethinking old relationshipsBirds, mammals and reptiles, Pandas and lesser pandas, Apes and humansv) Increasing sophistication of replicatorsEvolution lecture 8 - MacroevolutionA - Patterns of speciation in the fossil recordi) Phyletic gradualism (anagenesis) – transformation of an unbranched lineage to a different state (species)i) Cladogenesis – branching of new species from a parent species. Increases biological diversity.Both Anagenesis and Caldogenesis may occur in the same evolutionary tree.ii) Punctuated equilibria – long periods of stasis punctuated with sudden episodes of speciation.How sudden is sudden? Is this an artifact of the fossil record? What causes speciation events?B - Macroevolutionary mechanismsi) Preadaptations - structures that evolved in one context becomes co-opted for another function.ii) Morphology and developmentAllometric growth – slight changes in relative growth rates can have substantial changes in adult.Heterochrony – evolutionary changes in the timing or rate of developmentPaedomorphosis – retention of ancestral juvenile structures in a sexually mature adult.Homeosis – alteration in the placement of different body partsC - Patterns in the fossil record: extinctions and radiations, diversification and decimationi) Conventional representation - cone of increasing diversityAn example: the Burgess shale – how to make an arthropodii) Adaptive radiations: eg. origin of shells, origin of insect wingsiii) Mass extinctionsPermian extinction – extreme vulcanism and formation of PangaeaCretaceous extinction – asteroid hypothesis and/or climate change‘Mass’ extinctions affect different groups very differently. Why do some groups survive?Evolution lecture 9 - Systematics and classificationDefinitions: Phylogeny - evolutionary history of a speciesSystematics - study of biological diversity in an evolutionary contextTaxonomy - identification and classification of speciesA - How do we classify organisms? Three alternatives:i) Classical evolutionary systematics: uses information on both extent of divergence & the branching sequence.ii) Phenetics: makes no evolutionary assumptions and just uses info. on measurable similarities & differencesiii) Cladistics: only considers branching sequence and not degree of divergence.B – CladisticsTerminology: plesiomorphy (shared primitive character), synapomorphy (shared derived charactersi) Distinguishing plesiomorphy from synapomorphy using an outgroupii) What cladistics is good foriii) Problems with cladisticsiv) Parsimony or Occam’s razorC - Modern systematicsi) New toolsDNA comparisons – DNA-DNA hybridization, restriction mapping, DNA sequencingMolecular clocksii) Rethinking old relationshipsBirds, mammals and reptiles, Pandas and lesser pandas, Apes and humansD - Origin of lifei) What is life?ii) Early earth historyiii) Atmosphere of the early earthiv) Survival of the stablev) Increasing sophistication of replicators John Latto 6/21/07Evolution lecture 10 - Evolution and EcologyA - Adding evolution to ecological concepts and vice versai) Genetics and behavior - Genetics CAN code for behavior but behavior is not ALL geneticii) Evolution and behavior – optimal foraging theoryiii) Genetics and the environment – nature vs. nurture, heritabilityiv) Life history strategiesGrowth rate, number of offspring, size of offspring etc.v) Sex: why bother?Costs - recombination scrambles genotype- courtship and mating may be risky- finding a mate can be difficult- genome is dilutedSome possible reasons for the popularity of sex- related to the mechanics of DNA repair?- purges deleterious mutants and thus permits an increased genome size- allows a single, advantageous, mutation to be expressed in homozygote- in a patchy environment, disruptive effects of recombination may be advantageousB - Exam advicei) Write your own questionsii) Use your textbookiii) Look for the pointiv) Don’t overanalyzev) Read the questionvi) Re-read ALL the questions & answersvii) If you have to guess, guess intelligently!viii) Pay attention to ‘negative’ qualifiers. John Latto
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