BIOL 1001 Lecture Notes - Lecture 26: Speciation, Kiss Principle, Polytomy

• School: York University
• Department: Biology
• Course: BIOL 1001
• Professor: Alexander Mills

Document Summary

Phylogenetic trees: the unity & diversity of life. A series of dichotomies (usually) speciated into 2 species (sibling species at the moment) Branches: populations through time, adjacent branches = sister taxa, a taxon. A general term (for any name); whether . Tips represent : living groups, a group"s end in extinction. Phylogenetic trees are constructed from a series of dichotomies (usually: dichotomy. A division / contrast between 2 things . That are represented as being opposed / entirely different: polytomy. More than 2 descendant groups branch off. Homology: often a representative taxon is used, fundamental similarity due to descent from a common ancestor o the unity through kinship. Estimating phylogenies = building trees: phenetic approach, cladistic approach overall similarities the shared derived characteristics (synapomorphies) traits unique to each monophyletic group. Building trees = estimating phylogenies: analyze morphological and/or genetic characteristics, 2 strategies. A) phenetic approach: based on overall similarities (i. e. phenotypic similarities)