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UGA BIOL 1108 - 1-15-14

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Species Diversity Today Named and described 1 8 million o Vertebrates 62 000 o Insects 1 000 000 o Other invertebrates 300 000 o Mushrooms 32 000 o Plants 320 000 o Bacteria 9 850 o Archaea 400 There are probably at least 10 100 million more species alive today primarily eukaryote Some microbiologists estimate up to a billion prokaryotic species Taxonomic Hierarchy Linnaean taxonomic classification Domain Eukarya Kingdom Plantae Phylum Asteraceae Class Order Family Genus Species Helianthus Helianthus annuus Why study diversity in an evolutionary context i e The Tree of Life Basic info conveyed in phylogenetic tree Phylogenies provide current context for many biological questions relevant for society tolweb org tree Domains Bacteria Archaea prokaryotes Protists Plants Fungi Animals eukaryotes Goal organize diversity based on evolutionary history Challenge similar characters aren t necessarily due to common history Similar due to common ancestry o homology focus of phylogenetics Similar due to independent evolution not common ancestry o homoplasy analogy Are forearms in tetrapods homologous Two forelimbs two hind limbs Humerus radius ulna carpals metacarpals phalanges Evidence of common ancestry DNA how closely related they are fossil record indirect bone structure o Everyone in that group has same bone structure Is the capacity for flight a homology or homoplasy Homoplasy aka convergent evolution Evidence bird and bat bone structure are not similar enough part of answer common ancestor not all in that group can fly Homoplasy examples Placentals flying squirrel ground hog anteater mole mouse Marsupials flying phalanger wombat anteater mole mouse Ex skin flap is just needed as adaptation not related to evolution Cause of similarity for character of being red Shared ancestral trait homology all 4 in group of interest have trait Shared derived character homology D E have trait but came off same line Convergent evolution homoplasy B E have trait but came off different lines Constructing phylogenetic trees hypothesis of evolutionary history of groups Collect as much info as possible morphology biochemistry genes of relevant groups Identify homologous traits challenging Use shared derived homologous characters to construct timeline of character evolution phylogenetic trees Leopards lay amniotic eggs similar to turtle Nodes each node or branching point represents a common ancestor splitting into 2 evolutionary lineages Sister taxa closest relatives those terminal taxa that share the most recent common ancestor Clade monophyletic group Consists of most recent common ancestor and ALL descendants Paraphyletic descendants of reptiles minus birds Polyphyletic warm blooded animals mammals and birds We are undergoing a revolution in understanding evolutionary relationships Figuring out the tree of life for many more of those 1 8 million named species Tools and genetic characters will depend on the level of organization being assessed


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UGA BIOL 1108 - 1-15-14

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