lecture 2 and maybe 3

lecture 2 and maybe 3 - Carolus Linneus develop our current...

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Carolus Linneus develop our current system of classification, which is based on morphology. -- hierarchical system of classification --binomial nomenclature -- Kingdom--- Phylum----- Class---- Order---Family- Genus - Species -- more then 30 taxonomic characters are now recognized -- know names of animals, phylums, class, genus and species -- phylogeny takes a group of animals and attempts to relate them to other animals, either living or extinct. -- history of species development -- characters , features are used to construct phylogeny. - derived characters: new features Homology : character similarity due to common ancestry, most common recent ancestor has same feature Homoplasy: character similarity not due to common ancestry, i.e. the convergence of fusiform shape in aquatic animals i.e. due to external influence, environment -- many animals that are not evolutionary related have developed a fusiform shape b/c it is better adapted for swimming -- fusiform (torpedo, bullet type shape) - best shape for water movement -- most recent common ancestor of dolphin and penguin did not have this shape, -- convergent evolution : acquisition of same biological trait in unrelated species -- divergent evolution : the opposite of convergent, related species evolve different traits Cladistics : evaluation of information for tree building and classification -- allows to construct cladogram (branching diagram that shows how related organisms are and often gives the chronological order of character development) -- dichotomies: 2 way branch, each branch represents divergence of species, also has common ancestor. clad: group of organisms that share derived characters, feature that's not in ancestor Polarity: ancestral/descendant relationships among different character states -- Outgroup: amphioxous (chordate) that does not have vertebrate column -- used to compare to ingroup (all the vertebrates) -- fish, frog. .. -- A character state that separates out-group from in-group is the presence of vertebrate column - Vertebrate Clad: all animals have vertebrate column -- within vertebrate clad, there's tetrapod clad (that has limbs) and this clad excludes fishes -- vertebrate clad--- tetrapod clad-- amniotic clad-- hair (monkey) -- The top animal has all the characters present in lower clads + one unique character -- nested hierarchy of clads allows you to see chronological development of characters Synapomorphy: vertebrate column in synapomoprhic to fish, frog, lizard and monkey
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lecture 2 and maybe 3 - Carolus Linneus develop our current...

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