Flashcards in %Fossils Deck (14):
What are fossils?
Fossils are the preserved remains or evidence of ancient living things.
What is catastrophism?
Catastrophism is the idea that conditions and organisms on Earth change in quick, violent events.
What is uniformitarianism?
The principle of uniformitarianism states that geologic processes that occur today are similar to those that have occurred in the past. According to this view, Earth’s surface is constantly being reshaped in a steady, uniform manner.
Who created the idea of uniforitarianism?
James Hutton who lived in the 1700s. He believed the earth was older than one thousands years. He realized that erosion and such must take a long time.
What do we believe TODAY?
Today, uniformitarianism is the basis for understanding Earth’s past according to some people. But scientists also know that catastrophic events do sometimes occur. Huge volcanic eruptions and giant meteorite impacts can change Earth’s surface very quickly. These catastrophic events can be explained by natural processes.
Many Christians have a different view on this, but we are not going to get into that.
When is an organism more likely to become a fossil?
An organism is more likely to become a fossil if it has hard parts, such as shells, teeth, or bones. Also, an organism is more likely to form a fossil if it is buried quickly after it dies. If layers of sand or mud bury an organism quickly, decay is slowed or stopped.
What are the six ways fossils are preserved?
Preserved remains, carbon films, mineral replacement, molds, casts, and trace fossils.
What is preserved remains?
For actual remains of organisms to be preserved as fossils, an organism must be completely enclosed in some material over a long period of time. This would prevent it from being exposed to air or bacteria.
What are carbon films?
sometimes when an organism is buried, exposure to heat and pressure forces gases and liquids out of the organism’s tissues. This leaves only the carbon behind. A carbon film is the fossilized carbon outline of an organism or part of an organism.
What is mineral replacement?
Replicas, or copies, of organisms can form from minerals in groundwater. They fill in the pore spaces or replace the tissues of dead organisms. Petrified wood is an example.
What are molds?
A mold is the impression in a rock left by an ancient organism. A mold can form when sediment hardens around a buried organism. As the organism decays over time, an impression of its shape remains in the sediment. The sediment eventually turns to rock.
What are casts?
A cast is a fossil copy of an organism made when a mold of the organism is filled with sediment or mineral deposits.
What are trace fossils?
A trace fossil is the preserved evidence of the activity of an organism. Trace fossils include tracks, footprints, and nests.