Fossils Flashcards

Questions and Answers

Most fossils are found in what type of rock?

Sedimentary (correct)

Igneous

Metamorphic

Volcanic

Why are most fossils found in sedimentary rock?

Organisms die and are usually buried by sediments, or organisms leave imprints in sediments.

Which type of environment will result in good fossil specimens?

Desert

Volcanic area

High-energy environment

Quiet water (correct)

What type of fossil will be found in a high-energy environment?

Broken fossil fragments Signup and view all the answers

Can fossils occur in volcaniclasts?

True Signup and view all the answers

Are fossils found in intrusive igneous rocks?

False Signup and view all the answers

What happens to fossils when they go through metamorphism?

Destroyed by pressure and temperature. Signup and view all the answers

What is the first step in forming a fossil?

Creature dies, leaving behind body and/or footprint. Signup and view all the answers

What is the second step in forming a fossil?

Flesh rots away, bones and prints will remain. Signup and view all the answers

What is the next step in fossil formation after bones/prints are covered?

Bones/prints are covered by sediments. Signup and view all the answers

What is the next step after bones/prints are covered by sediments?

Sediment lithifies. Signup and view all the answers

What happens next in the fossilization process?

Minerals in the groundwater replace the bones. Signup and view all the answers

What is the next step after minerals replace the bones?

Bones become rock-like (fossilize). Signup and view all the answers

What is the final step in the fossilization process?

Uplift and erosion exposes the fossil. Signup and view all the answers

What are the 6 kinds of fossils?

Body fossils, replaced bones/teeth/shells, molds and casts, carbonized impressions, permineralization, trace fossils. Signup and view all the answers

What is a body fossil?

Whole body preserved. Signup and view all the answers

What is a replaced bones/teeth/shells fossil?

Hard parts preserved in rock. Signup and view all the answers

What is a mold fossil?

The hole left behind in rock when the shell is dissolved away. Signup and view all the answers

What is a cast fossil?

Mold that is filled by sediment that is lithified. Signup and view all the answers

What type of fossil is formed from soft or semi-soft organisms being pressed flat between layers of sediment?

Carbonized impressions. Signup and view all the answers

What is a permineralization fossil?

Minerals fill holes in porous material. Signup and view all the answers

What is a trace fossil?

Formed from marks left in or on sediments. Signup and view all the answers

What type of fossils can be seen with the naked eye?

Macrofossils. Signup and view all the answers

What type of fossils can only be seen with an electron microscope?

Microfossils. Signup and view all the answers

What type of organisms commonly make microfossils?

Plankton, pollen, algae, bacteria. Signup and view all the answers

What are the three special conditions required for fossilization?

Anoxic environment, rapid burial, presence of hard parts. Signup and view all the answers

When did archaea and bacteria appear?

3.7 BYA. Signup and view all the answers

When did the first eukarya plankton (protists) appear?

2.5 BYA. Signup and view all the answers

When did the first fungi appear?

1.5-1 BYA. Signup and view all the answers

When was the Cambrian explosion?

530 MYA. Signup and view all the answers

Study Notes

Fossil Formation and Types

Most fossils are found in sedimentary rock due to the conditions conducive to preservation.
Organisms typically die and get buried under sediments, or leave imprints in sediment as they move.
Quiet water environments are ideal for high-quality fossil specimens.

Fossilization Process

Step 1: Organism dies, leaving behind its body or footprints.
Step 2: Flesh decays, leaving bones or prints.
Step 3: Bones/prints get covered by sediments.
Step 4: Sediment undergoes lithification, turning into rock.
Step 5: Groundwater minerals replace the bones.
Step 6: Bones transform into rock-like structures (fossilization).
Final Step: Erosion or uplift exposes the fossil.

Types of Fossils

Body Fossils: Complete or parts of an organism preserved, e.g., woolly mammoth in permafrost.
Replaced Fossils: Hard parts (bones, teeth, shells) preserved through durable materials.
Mold Fossils: Impressions left in rock after the hard part dissolves, e.g., calcite shells.
Cast Fossils: Formed by sediment filling molds that become lithified.
Carbonized Impressions: Formed from soft organisms pressed flat between sediments.
Permineralization: Minerally-filled porous materials create fossils.
Trace Fossils: Indicators of activity (footprints, burrows, feeding traces).

Fossil Visibility

Macrofossils: Visible to the naked eye.
Microfossils: Require electron microscopes to observe; include plankton, pollen, algae, and bacteria.

Conditions for Fossilization

Fossilization requires three specific conditions:
- An anoxic environment (low oxygen).
- Rapid burial of the organism.
- Presence of hard parts within the organism.

Key Geological Timeline

3.7 billion years ago (BYA): First appearance of archaea and bacteria.
2.5 BYA: Emergence of the first eukaryotic plankton (protists).
1.5-1 BYA: Introduction of the first fungi.
530 million years ago (MYA): The Cambrian explosion marks significant biodiversity increase.

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Description

Test your knowledge of fossils with this set of flashcards! Learn about the types of rocks where fossils are typically found, the conditions that contribute to the formation of fossils, and the best environments for fossil preservation. Perfect for students seeking to deepen their understanding of paleontology.