Flashcards in Module 7 Deck (23)
1a. Define: Fossil
The preserved remains of a once-living organism
1b. Define: Petrifaction
The conversion of organic material into rock
1c. Define: Resin
A think, slowly flowing liquid produced by plants that can harden into a solid
1d. Define: Extinct
A term applied to a species that was once living but now is not
2. When a plant or animal dies, what is the most likely thing that will happen to its remains?
they will decompose
3. Which forms first: a fossil mold or a fossil cast?
A fossil mold forms first.
4. 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 or magma later and, when the filling hardens, it forms a cast.
5. What is required in order for petrifaction to occur?
water that has a lot of minerals in it
6. Why does petrifaction usually produce fossils with more information than fossil casts?
because fossil fasts retain only the shape and outer details of the fossil; when a fossil is petrified, its components are replaced with minerals; this means the entire fossil is preserved, which gives us more information than just the shape and outer details of the fossil
7. Can you learn much about the thickness of an organism from carbonized remains?
8. What type of organism is most likely to leave carbonized remains?
9. What is so nice about fossils that have been encased in amber or ice?
Thus, tissue and other soft plants tend to be preserved
10. What are the four general features of the fossil record?
I. Fossils are usually found in sedimentary rock. Since most sedimentary rock is laid down by water, it follows that most fossils were laid down by water.
II. The vast majority of the fossil record is made up of hard-shelled creatures like clams. Most of the remaining fossils are of either water-dwelling creatures or insects. Only a tiny, tiny fraction of the fossils we find are of plants, reptiles, birds, and mammals.
III. Many of the fossils we find are of organisms that are still alive today. Many of the fossils we find are of organisms that are now extinct.
IV. The fossils found in one layer of stratified rock can be considerable different from the fossils found in another layer of stratified rock.
11. What kinds of creatures make up the vast majority of the fossil record?
Clams and other hard-shelled animals
12. Approximately how many species of plants and animals have gone extinct in the last 400 years: a hundred, a thousand, ten thousand, or a hundred thousand?
13. What is a trilobite? Are trilobites extinct?
a creature that lived in the water and was covered in a hard outer covering; extinct
14. What is a placoderm? Are placoderms extinct?
a kind of fish; It was much like the fish we see today, but its head was covered in hard plates rather than scales; extinct
15. What is the uniformitarian explanation for how most sedimentary rocks formed?
sediments are laid down slowly over millions of years; Eventually, conditions change and the sediments harden to forms rocks. The conditions during which the sediments were laid down determine the type of sediment, which in turn determines the kind of rock formed.
16. What is the catastrophist explanation for how most sedimentary rocks formed?
formed in the worldwide flood; The depth, speed, and direction of the flood waters determined what type of sediments were laid down, which in turn determined the kind of rock formed.
17. What is the uniformitarian explanation for why different fossils are formed in different straits?
the different fossils found in different layers result from the fact that different plants and animals existed at different times in any given region
18. What is the catastrophist explanation for why different fossils are formed in different straits?
the different fossils in different layers are the result of the fact that different kinds of organisms were trapped and preserved during different stages of the flood
19. What major speculation must uniformitarians make when studying geology?
how millions of years of time affect the processes we see working today