Fossils and Taxonomy
Darwin 1859-On the Origin of Species by means of Natural Selection
Pre: unchanged flora/fauna since creation
Post: All life interrelated-part of the animal kingdom
Evolution: Unidirectional Change
Hooke/Steno/Cuvier all recognized many organisms in fossil record not present today
Major Revolutions in Life occurred at ERA boundaries
Species analagous to the atom in that they are the basic discrete building block (genetics on
modern organisms)
Fossils: remains of past life-very useful for BIOSTRATIGRAPHY (more later)
Preservation is the key:
Usually need: hard parts, oxygen poor environment, rapid burial
Types of Fossil Preservation:
Original Hard Parts
Replacement
Original Soft Parts
Molds/impressions
Carbonization
Permineralization
Analysis of PHYLOGENY (History of Species)
Clades: group of organisms with a common ancestor
Often based on traits that appear in the fossil record
Organisms grouped at various taxonomic levels:
Kingdom
Phylum
Class
Order
Family
Genus
Species
Example: Animal/Chordata/Mammalia/Primates/Hominidae/Homo/Homo sapiens
Eubacteria/Archaeobacteria = Prokaryotes (>3 billion years)
Protista/Fungi/Animalia/Plantae = Eukaryotes