Question

Which of the following is most likely to be preserved in the fossil record?

Select one:
a. A clam shell made of calcite
b. Soft parts of a reptile
c. A gastropod shell made of aragonite
d. Wood cellulose
e. Sponge spicules made of silica

Answer 1

Clam shells made of calcite are the most likely to be preserved in the fossil record because calcite hard parts can easily mineralize and are more durable over time, increasing their chances of fossilization. The correct option is (a).

Step-by-step explanation:

The question revolves around which type of material is most likely to be preserved in the fossil record. Among the options given, a clam shell made of calcite is the most likely to be preserved. This is because calcite is a mineral with a hardness of 3 that is readily found in many marine organisms such as shells. The fossilization process often favors the preservation of hard parts, mainly bones, teeth, or shells, due to their ability to mineralize and withstand the test of time, which makes them more likely to form fossils compared to the soft parts of organisms.

The geological record indicates that invertebrate animals from the marine environment commonly become fossils, and this includes organisms with shells made of calcite, such as clams. In contrast, soft parts of animals, gastropod shells made of aragonite (which is an unstable polymorph), wood cellulose, and silica-based sponge spicules are less likely to fossilize with the same frequency or durability as calcite shells.