PHYLOGENETIC CLASSIFICATION THE NEW TAXONOMY

Let’s review Linnaean Taxonomy… Organisms arranged based upon external physical (morphological) characteristics… basically what does the organism look like. Placed into successive groups as characteristics become more specific Last two divisions Genus species represents the scientific name of the organism. Identifies that specific organism and no other Scientific names eliminate the confusion of common names; written in Latin to avoid language barriers Ex: cougar, puma, mountain lion are all the same animal classified as Felis concolor

Internal skeleton w/ backbone Eukaryotic, Multicellular, Heterotrotrophs Internal skeleton w/ backbone Hair, glands to produce milk All teeth sharp, pointed CATS DOGS BEARS

Linnaean taxonomy does not take into consideration genetic relationships(cause they didn’t know about DNA!) or the effects of natural selection on adaptation related to homologous structures, convergence, etc! Looks can be deceiving!

Phylogenetic Classification Takes into account species patterns of decent, evolutionary relationships using characters: the inherited features that vary among species Morphological: physical characteristics produced by proteins coded for by DNA: structure/function Biochemical: DNA/RNA sequences( mutation rates, numbers of mutations) Most modern form of classification based on analysis of phylogenies: CLADISTICS Construction of a diagram illustrating the genetic evolutionary relationships called CLADOGRAM or PHYLOGENETIC TREE

ANCESTRAL TRAIT: TRAIT ALL SHARE ANY CLADE OF ORGANISMS REPRESENTED ALONG A STRAIGHT LINE IS NOT EXTINCT AND EQUALLY EVOLVED ANCESTRAL SPECIES OUTGROUPS CLADE SOFT SHELLED HARD SHELL PARADE THOUGH NOT REPRESENTED HERE THE DISTANCE BETWEEN NODES = THE TIME BETWEEN DIVERGENT EVENT DERIVED TRAITS EVOLVED CHARACTERISTIC UNIQUE TO GROUP NODES BRANCHES OCCUR AS RESULT OF DIVERGENCE ANCESTRAL TRAIT: TRAIT ALL SHARE ORIGINATED IN COMMON ANCESTOR, OLDEST TRAIT CLADOGRAMS ASSUME THE GREATER NUMBER OF SHARED DERIVED TRAITS BY GROUPS THE MORE CLOSELY RELATED THE GROUPS ARE AND SHARE A COMMON ANCESTOR