BIOL 152 1st Edition Lecture 6 Outline of Last Lecture I Speciation and species a Isolation i Prezygotic ii Postzygotic b Case Study Rhagoletis pomonella i Life cycle ii Parasites iii Hawthorns 1 Small fruit 2 High nutritional value 3 Maggots barely burrow 4 High wasp mortality 5 Late ripening iv Apples 1 Large fruit 2 Low nutritional value 3 Maggots burrow deep 4 Low wasp mortality These 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 ripening v Types of species 1 Biological 2 Ecological 3 Morphological 4 Phylogenetic vi Types of isolating mechanisms 1 Postzygotic a Hybrid inviable or sterile 2 Prezygotic a Geographical b Mechanical c Ecological d Behavioral vii Types of speciation 1 Allopatric 2 Sympatric didn t get to within lecture Outline of Current Lecture I Reconstructing Evolutionary History a Darwin proposes Descent with Modification i Insight from others 1 Hutton s Gradualism 2 Lyell s uniformitarianism 3 Lamark s perspectives on fossils b Building phylogenetic trees i Evolutionary Patterns ii Tracing genealogies c Analogous vs Homologous characteristics d Hennig and phylogenetic characteristics i Apomorphies ii Plesomorphies iii Synapmorphies iv Symplesiomorphies e Phylogenies and classifications i Monophyletic groups ii Paraphyletic groups iii Polyphyletic groups II Cycling Carbon a Charles Keeling Current Lecture Allopatric speciation various changes in nature causing two populations to grow distinct Phylogenetic perspective Two species have common ancestry Should be classified together Charles Darwin History of life on Earth o Personal observations o 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 conditions o THEN Species change gradually over long time periods Species originate and go extinct Shared features common ancestry o 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 records o Supported by comparative morphology o Tested MANY times Most recently by molecular data Never falsified Process yielding DWM pattern o Begin with ancestral species o Hypothesize speciation event o New lineages evolve novel features Descent with Modification o We are all descendants of our ancestors o NONE of us are exact duplicates of our ancestors o We all share some of our ancestors characteristics o All of us resulted from descent with modification Tracing ancestries o Family trees o Genealogies o Discovering ancestors descendant lineages o Features shared by descendants and ancestors help trace lineages o Novel features in descendants identify individuals Reconstructing Evolutionary History Inferences from genealogical history o There is only one accurate history of life on Earth o All extant species have ancestors o Lineages of related species can be hypothesized Related species share features o Shared features may indicate common ancestry Analogous vs Homologous characteristics Using 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 symplesiomorphies o Based on homology Modified but still used today Phylogenies classification Propose hypothesis of evolutionary history phylogeny Develop classification based on hypothesis o Use only homologous features o Hierarchy should reflect hypothesized relationships Classification system Kingdom Phylum Class Order Family Genus Species Groups Monophyletic includes a common ancestor and all its descendants Paraphyletic includes a common ancestor and some but not all descendants Polyphyletic does not include common ancestor Classification Summary Based on phylogenetic hypotheses Included groups should by monophyletic Bring order to biological diversity Hierarchal Predictive
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