BIOLOGY 1M03 Lecture Notes - Lecture 15: Ice Shelf, Molecular Clock, Absolute Time And Space
Document Summary
Phylogenies : provide information on evolutionary relationships and the average age of divergence (cid:1) (cid:1) years (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) Fossils: provide information to convert relative age to absolute age in. Clade must be at least x years old depending on placement of fossil. One a molecule is established as clock-like: used as a molecular clock to calibrate time trees without fossils, rules of thumb: for rate of sequence divergence per millions of years. A time tree is a time scaled phylogenetic tree, calibrated to absolute time in years using fossils or other geologic ages (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) The timing of divergence events among clades (genera, species, populations ) Penguin evolution crown divergence of penguins is about ~20 my compare to concurrent events in antarctica and globally ice shelves expanding and contracting, important to the habitat of the penguins (climate change?)
