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KU BIOL 152 - Reconstructing Evolutionary History

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BIOL 152 1st Edition Lecture 6 Outline of Last Lecture I. Speciation and speciesa. Isolationi. Prezygoticii. Postzygoticb. Case Study: Rhagoletis pomonellai. Life cycleii. Parasites!iii. Hawthorns1. Small fruit2. High nutritional value3. Maggots barely burrow4. High wasp mortality5. Late ripeningiv. Apples1. Large fruit2. Low nutritional value3. Maggots burrow deep4. Low wasp mortalityThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.5. Early ripeningv. Types of species1. Biological2. Ecological3. Morphological4. Phylogeneticvi. Types of isolating mechanisms1. Postzygotica. Hybrid inviable or sterile2. Prezygotic a. Geographical b. Mechanicalc. Ecological d. Behavioralvii. Types of speciation1. Allopatric2. Sympatric (didn’t get to within lecture)Outline of Current Lecture I. Reconstructing Evolutionary Historya. Darwin proposes “Descent with Modification”i. Insight from others1. Hutton’s Gradualism2. Lyell’s uniformitarianism3. Lamark’s perspectives on fossilsb. Building phylogenetic treesi. Evolutionary Patternsii. Tracing genealogiesc. Analogous vs. Homologous characteristicsd. Hennig and phylogenetic characteristics i. Apomorphies ii. Plesomorphies iii. Synapmorphiesiv. Symplesiomorphiese. Phylogenies and classificationsi. Monophyletic groupsii. Paraphyletic groupsiii. Polyphyletic groupsII. Cycling Carbon a. Charles KeelingCurrent LectureAllopatric speciation- various changes in nature causing two populations to grow distinctPhylogenetic perspective:- Two species have common ancestry- Should be classified togetherCharles Darwin- History of life on Eartho Personal observationso Insight from others James Hutton (geologist)- Demonstrated that the Earth went through gradual change Charles Lyell (geologist)- Uniformitarianism- the processes we’ve seen on Earth that have been happening a very long time Lamark (Biologist)- Fossils show change over time- Biodiversity occurred as species adapted to environment- Darwin Synthesizes:o IF Change is gradual Time periods are long Species adapt to local conditionso THEN Species change gradually over long time periods Species originate and go extinct  Shared features= common ancestryo THUS: DESCENT WITH MODIFICATION- Darwin concluded:o Earth’s biodiversity resulted from descent with modification Species originate and go extinct Extant species have extinct ancestors A “phylogenetic tree” diagram can display this ancestry- An evolutionary “pattern”o Observed in fossil recordso Supported by comparative morphologyo Tested MANY times Most recently by molecular data Never falsified- Process yielding DWM pattern o Begin with ancestral species o Hypothesize speciation evento New lineages evolve novel features- “Descent with Modification”o We are all “descendants” of our ancestorso NONE of us are exact duplicates of our ancestorso We all share some of our ancestors’ characteristicso All of us resulted from descent with modification- Tracing ancestrieso Family treeso Genealogieso Discovering ancestors >> descendant lineageso Features shared by descendants and ancestors help trace lineageso Novel features in descendants identify individualsReconstructing Evolutionary History- Inferences from genealogical historyo There is only one accurate history of life on Eartho All extant species have ancestorso Lineages of related species can be hypothesized  Related species share featureso Shared features may indicate common ancestryAnalogous vs. Homologous characteristicsUsing homology to trace ancestry- Willi Hennig o Father of phylogenetic systematics- Entomlogist- Developed principles to reveal ancestral (plesiomorphic) and derived (apomorphic) features- Shared derived features= synapomorphies- Shared ancestral features= symplesiomorphieso Based on homology- Modified, but still used todayPhylogenies >> classification- Propose hypothesis of evolutionary history (phylogeny)- Develop classification based on hypothesiso Use only homologous featureso Hierarchy should reflect hypothesized relationshipsClassification system:Kingdom >> Phylum >> Class >> Order >> Family >> Genus >> SpeciesGroupsMonophyletic- includes a common ancestor and all its descendantsParaphyletic- includes a common ancestor and some, but not all descendantsPolyphyletic- does not include common ancestorClassification Summary - Based on phylogenetic hypotheses- Included groups should by monophyletic- Bring order to biological diversity- Hierarchal-


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