BIOL 201 1st Edition Lecture 10Outline of Previous LectureI. Definition of SenescenceII. Evolution of Aginga. Late-acting deleterious mutationsb. Antagonistic pleiotropyc. Natural Aging ExperimentIII. Cost of sexa. Survival Costsb. Reproductive costsIV. Why sex?a. Fixation of rare beneficial mutationsb. Adaptation to variable environmentsc. Deleterious mutationsOutline of Current LectureI. Classificationa. Taxonb. LinnaeusII. Phylogeneticsa. Phylogenetic treeIII. Properties of phylogenetic treesa. Unrooted treeb. Rooted treec. Monophylyd. Paraphylye. PolyphylyIV. Building phylogenetic treesa. Characteri. Discreteii. continuousb. Homologousc. Character stated. Phylogenetically informative/synapomorphye. ParsimonyCurrent LectureI. Classificationa. Taxon: plural is taxa, species or higher order group of organismsb. Linnaeus: hierarchical classification scheme like kingdom, phylym, class, order, family, genus, speciesi. Species found within genus which are found within families and so on and so forth up to kingdomii. Things get more dissimilar as you move up to kingdomII. Phylogenetics- can show current species, extinction, and speciation whichis 2 branches splitting from onei. Very old, Darwin used in The Origin of Speciesb. Phylogenetic treei. Past at the bottom and present at the topii. Don’t have to have every species in each treeiii. Ends can be species, families, species, or anything elseIII. Properties of phylogenetic treesa. Unrooted tree- shows relationships between taxa but not the order in which they evolveb. Rooted tree- shows relationship as well as the order of evolutioni. Node: branch points and each represents speciationii. Internal branches don’t lead to terminal taxaiii. Terminal taxa: taxa at ends of branchesiv. Peripheral branches do lead to terminal taxav. Need an outgroup to determine relationship between other taxavi. You can rotate rooted trees around any node and they are still the same despite different orderc. Monophyly: group that includes an ancestor and all of its descendantsi. Clade: monophyletic groupd. Paraphyly: at least on of the descendants is excluded; means tree is wrongi. Humans should be included in groupPongidae with chimps, gorillas, and orangutans. Also birds should be included in reptile group but commonly are excluded. e. Polyphyly” at least one excluded member is ancestral to some of the others; means tree is wrongIV. Building phylogenetic treesa. Character: feature that is thought to vary independently of other features and is homologous among taxa, gather a bunch to make a phylogenetic tree [normally 60-100]i. Discrete: finite number of states like coat color being brown or black ii. Continuous: infinite # of states like height or length of femurb. Homologous: derived, with or without modification, from a common ancestori. Ex: vertebrate limb bones c. Character state: one of the alternative conditions of the characteri. Like whether ulna of vertebrate limb bones are fused to radius or notd. Phylogenetically informative/synapomorphyi. Phylogenetically informative: will help us figure out the relationship between set of speciesii. Polytomy: more than 2 branches coming out of a node1. Soft: know 2 branches come out and not sure about the third yet2. Hard: know 3 branches come out at roughly the same timeiii. Synapomorphy: character states that are shared and derived, have to be in order to be informative1. Don’t have to be shared by everybody and shouldn’t be2. Ancestral and derived characters are opposite3. Have to be given example trees if given more than 3 traits4. Use an outgroup to determine what’s ancestral and what’s derived; usually use multiplee. Parsimony: the tree with the fewest evolutionary changes is most likely to be right; not the only criterion for creating phylogenetic treesi. If 2 trees have same number of evolutionary changes then they are equally