Gen Science Module 7 Flashcards
Fossil
The preserved remains of a once-living organism.
Petrifaction
The conversion of organic material into stone.
Resin
A thick, slowly flowing liquid produced by plants that can harden into a solid.
Extinct
A term applied to a once living species but now is not.
When a plant or animal dies, what is the most likely thing that will happen to its remains?
They will decompose. Fossilization is a rare exception to this rule.
Which forms first: a fossil mold or a fossil cast?
Fossil mold.
Describe the process of a cast forming, indicating when the mold has formed and when the cast has formed.
The remains of a plant or animal are encased in sediment and the sediment eventually hardens into rock. As the remains of the plant or animal disintegrate, a hole is left in the rock, in the shape of the original remains. That is the mold. The mold might fill up with sediment later and, when the sediment hardens, it forms a cast.
What is required in order for petrifaction to occur?
Petrifaction requires water that has a lot of minerals in it.
Why does petrifaction usually produce fossils with more information than fossil casts?
Fossil casts retain only the shape and outer details. When a fossil is petrified its components are replaced with minerals - preserving the entire fossil.
Can you learn much about the thickness of an organism from carbonized remains?
No, because they come as a result of the organism being squished, so that only gives you a two dimensional view.
What type of organism is most likely to leave carbonized remains?
Plants.
What is so nice about fossils that have been encased in amber or ice?
Fossils encased in amber or ice do not decompose as quickly as other fossils. Thus, tissue and other soft parts which usually are not preserved tend to be preserved very well.
What are the four general features of the fossil record?
The four general features of the fossil record are:
What kinds of creatures make up the vast majority of the fossil record?
Clams and other hard-shelled animals make up 95% of the fossil record.
years: a hundred, a thousand, ten thousand, or a hundred thousand?
Approximately 1,000 species have gone extinct over the last 400 years.