Fichas
Fossils Key Definitons
Fichas del conjunto (29)
- 1Fossil• Any trace of past life
• May be:
→ Parts of organisms (e.g. shells, teeth)
→ Traces of organisms (e.g. footprint, burrow) - 2Organism• Individual life form
• May be a single cell or multicellular
• May be preserved as fossils - 3Body Fossil• Hard part of organism
• Such as the skeleton or shell - 4Replacement• Atom by atom substitution
• of one mineral for another - 5Dissolution• Minerals that make up fossils dissolved away and removed
• in solution by rainwater - 6Taphonomy• Study of the process of fossilisation
• From death to discovery of fossil
• Overlap between biology and sedimentary geology - 7Mould• The impression of the outside or inside of a fossil
- 8Cast• In-filled fossil void
• Usually iwth another mineral - 9Extant• Organisms still alive today
- 10Extinct• Organisms no longer alive tody
- 11Death Assemblage• Collection of organisms found in different place and position than they occupied in life
• Such as collection of disartucilated shells - 12Disarticulated• Organsims found as fragments
• Such as separate shells or parts of trilobites - 13Life Assemblage• Collection of organisms found in sediment
• In same position as when alive
• e.g. Bivalve in burrow - 14Geopetal Structure• Way up structure
• e.g. Coral/Bivalve in life position - 15Derived fossil• Weathered out of one rock
• Re-deposited in another
• May give conflicting dates - 16Ornament• Expressed on surface of the fossil
• e.g. ribs/spines - 17Robustness• Ability of fossil to resist abrasion
• More robust fossils more likely to be preserved whole - 18Articulated• Organisms found whole or connected
• as in life - 19Littoral Zone• High-energy area between high and low tide
- 20Anoxic/Aerobic conditions• Lack oxygen
• Unsuitable for life - 21Trace Fossil• Formed by benthonic infaunal and benthonic epifaunal organisms
• Can be aquatic or terrestrial
• Although preservation potential for terrestrial is poor - 22Tracks• Footprints of an organism made when moved along sediment
- 23Resting Traces• Type of trail as whole body of animal stops moving (rests)
- 24Terrestrial• Anything formed on land
- 25Bioturbation• Burrowing or working the sedimnent in a way that disturbs the bedding
• Caused by living organisms - 26Substrate• Name given to sediment or rock on sea floor
- 27Catastrophism• The theory that changes in Earth's rust during geological history
• have resulted from sudden violent and unusual short-lived events - 28Gradulism• Assumes the change comes about gradually or that change is gradual in nature.
• Applied in evolution (phyletic gradulism) where slow changes transform species - 29Uniformitarianism• Slow, incremental changes (e.g. erosion) created all geological features
• The present is the key to the past
• Assumes processes now same as in past