Fossils

Question 1

What is a fossil?

Answer 1

• Preserved evidence (remains or traces) of ancient life

Question 2

What are the two types of fossils?

Answer 2

1. body fossils (any part of an organism i.e bones, teeth, skin)
2. trace fossils (evidence of their day-to-day activities i.e footprints, trails, or burrows)

Question 3

An organism may become a fossil only if:

Answer 3

it is protected from decomposition, scavenging, weathering erosion, or any other process that may destroy the remains

Question 4

How are fossils made?

Answer 4

• Over time, high spots wear down, and low spots fill up, the sediments are slowly buried and turn to rock
• Low spots result in more fossils due to burial and protection from that burial from destruction
• More rapidly an organism is buried, the more likely it is to fossilize.
• Once an organism is buried, chemical changes may take place that turn it into a fossil.
• Burial is the most common way to make a fossil, but there are others

Question 5

Unaltered fossil preservation methods

Answer 5

1. Freeze (unaltered hair, muscle, and blood)
2. Mummification/Desiccation (Jerkify)
3. Encasement (cover it in something sticky): mummification can also accompany encasement in amber, or tar. Soft tissues break down, but bones get “pickled”. The original hard parts are still there, but turn black and smell like tar.

Question 6

Altered fossil preservation methods

Answer 6

1. Replacement
2. Permineralization (fill the void)
3. Petrifaction (petrify it)
4. Recrystallization
5. Carbonization (leave a film)

Question 7

Molds and Casts (imprints and replicas)

Answer 7

• Mold: stamp organism into sediment, then removed

- Cast: fill the mold up with other sediment and remove the mold (an exact replica of the fossil)

Question 8

Chances of anything becoming fossilized are slim, and the chances we find it are:

Answer 8

even slimmer

Question 9

Replacement

Answer 9

original bone or shell material is dissolved and another mineral immediately takes its place i.e pyrite (fool’s gold) and silica (quartz)

Question 10

Permineralization

Answer 10

water flows through pores and deposits minerals, common in bones.

Question 11

Petrification

Answer 11

permineralization + replacement, common in wood

Question 12

Recrystallization

Answer 12

change the crystal structure or make the crystals bigger

Question 13

Carbonization

Answer 13

bury it and squeeze all the water and other volatiles out until there is only a film of carbon left on the rock