What's a fossil? Flashcards
What’s a fossil?
Preserved remains or traces of organisms from the remote past
What are some examples of traces?
foot tracks or trails
What’s an Index fossil?
Fossils that are good to be used for relative dating
When was the 1st life?
3.5 Ga (maybe)
How do organisms get preserved?
- ) Buried in a protective medium quickly
2. ) Presence of hard parts
What and how old is the first fossil?
Algae and 3.7 Ga
What’s the best protective medium for preservation?
Marine setting
What are the 3 major types of fossils?
Body, trace, and chemical
What’s a body fossil?
Preservation of an actual body part
What’s a trace fossil?
Preservation of a trail, track, borrow, or structure
What’s a chemical fossil?
Chemicals or isotopes found in rocks that have an organic structure
Does DNA last forever?
NO
What are the different types of body fossilization?
Unaltered hard parts, unaltered soft parts, and altered hard parts
What are direct fossils?
Involve the former hard or soft parts of an organism
How can unaltered soft parts be preserved?
Frozen, desiccated, pickled, and entrapment
What’s desiccated?
The removal of moisture
What’s pickled?
Where organisms are hung and tossed in a swamp
What’s entrapment?
It’s like sap or amber
How can unaltered hard parts be preserved?
Entombment and pickled
What’s entombment?
Where a dead body is put into a tomb or stuck in tar
How can altered hard parts be preserved?
Leached, recrystallization, and carbonization
What type of fossil does direct fossils fall under?
Body
What’s leached?
Where the organic parts are gone and dull of luster
What’s recrystallization?
Change in chemical or crystal form of skeletal material without change in chemical composition
What’s carbonization?
Where carbon is only left. O, H, and N are driven off
What are indirect fossils?
Molds and casts of hard parts
What type of fossil does indirect fossils fall under?
Body
What are the different types of trace fossilization?
- ) tracks, trace, footprints, burrows, and bores
- ) fecal material (coprolites)
- ) Eggs
- ) gastroliths
What are gastroliths?
Stones that can be eatan or hard concretion that’s int he stomach
How are fossils used in forensics?
Evidence from fossils. Body fossils, the skull, trace fossils, bites, patterns, etc.
What’s hopanes and which major type of fossils does it fall under?
Evidence for photosynthetic bacteria in rocks 2.7 Ga and chemical fossils
What’s steranes and which major type of fossils does it fall under?
Evidence for higher life forms (eucaryotes) in rocks 2.7 Ga and chemical fossils
