Chapter 18

Question 1

Which fossils provide the least altered remains available to paleontologist?

Answer 1

Amber and freezing. Can preserve incomplete DNA sequences, fur, tissue and even veins.

Question 2

What is permineralization and replacement?

Answer 2

Common modes of fossilization and can form when structures are buried in sedicments and dissolved minerals either replace the original mineral content or precipitate in and around it. Shape is preserved, composition is altered.

Question 3

Where do natural molds and casts originate from

Answer 3

When remains decay after being buried in sediment. They do not preserve internal details.

Question 4

What are molds?

Answer 4

Consist of unfilled spaces

Question 5

What are casts?

Answer 5

Form when new material infiltrates the space, fills it and hardens into rock

Question 6

What is a trade fossils?

Answer 6

Fossils that trace behavior. Ex; fossilized feces or trackways.

Question 7

What are body fossils?

Answer 7

Fossils that trace form

Question 8

Formation of most fossils depends on three key features:

Answer 8

1. Durability
2. Burial; usually in a water-saturated sediment
3. Lack of oxygen; which inhibits scavenging and bacterial breakdown)
   Each slow decomposition and makes fossilization more likely.

Question 9

Taphonomy:

Answer 9

(Taphos= burial) The study of the fossilization process.

Question 10

Tophonomic bias:

Answer 10

Difference between what was once alive and its representation in the fossil record. Ex; orgamisms with hard body parts preserve more easily than those that are entirely soft bodied

Question 11

What is the pull of the recent?

Answer 11

The improvement of the giological and fossil records through time