Fossils and Evolution

What are fossils and what do they tell us?

Fossils are evidence of past life that provide indightd into evolutionary history and the biological diversity of ancient organisms.

Under what conditions do fossils typically form?

Fossils generally form in low-lying, sediment-rich environments like swamps, estuaries, and lakes, where rapid sediment accumulation occurs

What role do hard body parts play in fossilization?

Only hard, mineralized body parts like bones, teeth, and shells tend to fossilize because soft tissues decompose quickly

How do low-oxygen environments affect fossil formation?

Low-oxygen (anoxic) environments slow decomposition by limiting scavengers and microorganisms, increasing the chances of fossilization

How does erosion affect fossil discovery and destruction?

Erosion can expose fossils for discovery but can also destroy them if they are not found in time.

What is permineralization in fossilization?

Permineralization is when minerals like silica or calcite gradually replace an organism's hard parts, such as bones, to form a fossil.

What are compression fossils?

Compression fossils form when organic material is compressed by sediment, creating a thin carbon film that preserves the organism’s outline, especially in plants.

What is the difference between cast and mold fossils?

Molds form when an organism decomposes, leaving a cavity, while casts form when that cavity is filled with minerals, creating a 3D replica.

What are trace fossils?

Trace fossils capture evidence of an organism’s activity, such as footprints, burrows, or coprolites (fossilized excrement).

How do fossils contribute to our understanding of evolutionary biology?

Fossils provide direct evidence of ancient organisms, evolutionary transitions, and allow us to infer relationships between extinct and living species.

What biases exist in fossil formation?

Fossils are more likely to form from common organisms, in lowland/marine environments, and from organisms with hard body parts, leading to geographical and structural biases