Unit 1: Fossil Record
Is Paleontology a Science?
Natural science approach
-Inductive reasoning
-Deductive reasoning
Inductive Reasoning (logic):
-Through accumulation of observational data of natural phenomena will the e explanation emerge?
-Bottom up approach
- Observations->pattern->tentative hypothesis->theory
Deductive Reasoning
Works from the more general to the more specific
Top-down approach
Theory->hypothesis->observation->confirmation
Paleontology Applications
Biostratigraphy:
-Traditional application of paleontology was to date rocks using biostratigraphy
Life on Different Worlds
-Plants and animals were different in the past
-Paleontology permits us to envision the variety of life that can exist on worlds such as ours
Climate and Biodiversity
-Earth has gone through dramatic shifts through history that has directly impacted life
Extinction:
-Fossil analysis tells us extinction is a natural ongoing phenomenon with the occasional mass extinction thrown in
Nature of the Fossil Record
Over 300,000 fossil taxa have been described
Approximately 1400000 living species have been described
Putting fossils in perspective
-Described fossils only represent about 1.6% of described living forms
-0.18% of probable living fauna
-750,000 catalogued living species (8000 fossil) are insects
-Insects are delicate and not usually preserved
-Other fossil groups are therefore of more use in gauging completeness of the record
Useful determinant fossil groups should:
-Be readily preserve
-Have many species
9 fossil groups meet the above criteria
1. Protozoa
Single celled shelled marine or freshwater microorganisms
Often very abundant
Highly useful in pale environmental
Research and petroleum industry
Ex. Foraminifera
2. Archaeocyathida
Extinct marine organisms that colonized warm shallow seas during the early to middle Cambrian
Look like ice cream cones
3. Peripheral
Or sponges are primitive sessile...