Biol 3350 1st Edition Lecture 21 Outline of Last Lecture I. InfluenzaII. Influenza EvolutionIII. Tracing Origins of Pandemic Flu StrainsIV. Virulence as Coincidental EvolutionV. Virulence as Short-Sighted EvolutionVI. Virulence as a Trade-OfVII. Trade-Ofs: PredictionsVIII. Overdominance and DiseaseIX. Some symptoms are actually an adaptive response to illnessOutline of Current Lecture I. TaxonomyII. SystematicsIII. PheneticsIV. Types of distance measuresV. CladisticsVI. Terminology of CladogramsVII. Parsimony AnalysisCurrent LectureI. Taxonomya. Linneaus developed a system of binomial nomenclatures that we still use todayb. Species  genus  family  order  class  phylum  kingdomc. Phylogenetic trees are hypothesesi. Don’t know for sure that they are the real truth because evolution is a very long process and hard to observe entirelyd. The tree of life must be discoveredII. Systematicsa. Classification of biological diversityb. Grouping species by similaritiesc. Two methods of classification:i. Phonetics (taxonomy)ii. Phylogenetics III. Pheneticsa. Phenotypic traits are used to group speciesThese 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.b. Average degree of similarity across many traitsc. Not evolutionary basedd. Phenotypes are a result of interaction with the environmenti. If group A and B live in the same environment, they may have similar adaptations (not necessarily similar because of similar ancestry)e. Dendrogram or phenogram – phenetic treei. Branch order and branch length are important ii. Branch length tell us how similar two taxa areiii. Branch length reflects degree of nucleotide diferenceIV. Types of distance measuresa. Euclidean distance: straight line distance between two taxa using Pythagorean theoremi. Using statistical technique to determine overall similarityii. Mean distance = sum of all Euclidean distances divided by the number of charactersiii. Genetic distance (D) – average distance between two taxa based upon some measure of genetic identity or similarity1. Smaller D  two taxa are closely related2. Measuring mutational accumulation in the absence of natural selectionV. Cladisticsa. Homology: based on traits that are identical in two or more species because theyare descended from a common ancestori. Informativeii. Cladistics are based on the concept of homologyb. Homoplasy – shared traits between taxa that have diference common ancestorsi. Uninformative – only confuses cladisticsii. Causes by similar environments, convergence, or parallel evolutionc. Groups taxa according to common ancestryd. Distinguished from homoplasiesi. The more characters you use, the more certain you can be that your hypothesis is correcte. Convergent evolution – same because same environmentf. Homology – shared ancestryg. Parallel evolution – evolved in similar sequence but NOT because of same common ancestorh. Evolutionary reversal – mutation change back to originalVI. Terminology of Cladogramsa. Monophyletic group – contains all the descendants of a common ancestorb. Paraphyletic – contains some but not all of the descendants of a common ancestorc. Polyphyletic – group does not contain common ancestord. Internal node – ancestore. Branch length – number of changesVII. Parsimony Analysisa. Based on the principle of parsimonyi. The optimal solution requires the fewest changesii. Taxa are arranged in a phylogeny such that the smallest number of evolutionary changes is requirediii. Tree is called a cladogram or phylogenyiv. Branch length = evolutionary steps or number of