A scientist wants to determine the age of a rock. The rock contains an index fossil and an ancient relative of a living organism. Which is more useful for dating the rock, and why?
Answer: an ancient relative of a living organism would be more useful for dating the rock because fossils in a rock layer represent what lived during the period the rock was deposited.
For dating a rock, it would be more useful to use index fossils because it indicates the relative age of the rock in which it is found. Index fossils come from species that were widespread but existed for a relatively brief period of time.
That is correct. When dating rock layers, one of the main methods used is relative dating based on the presence and sequence of index fossils. Index fossils are organisms that existed for a relatively short period of time but were widespread geographically. By using the known age of an index fossil, scientists can determine the relative age of the rock layer that contains it.
However, it's important to note that relative dating alone doesn't give us the exact age of the rock; it only provides a relative order of events. To determine the absolute age of the rock, scientists often use radiometric dating, which relies on the decay of radioactive isotopes in certain minerals. In this case, an ancient relative of a living organism would be more useful for radiometric dating because it allows us to determine the precise age of the rock by comparing the ratio of parent isotopes to daughter isotopes in the fossil.
To determine the age of a rock, scientists often rely on the concept of index fossils and the Principle of Fossil Succession. Index fossils are widespread and existed for a relatively short period of time, making them useful for dating rocks within a particular time frame. However, in this case, an ancient relative of a living organism would be more useful for dating the rock.
The reason is that the presence of an ancient relative of a living organism indicates that the rock was deposited during a specific time in Earth's history. This type of fossil provides more precise information about the age of the rock because it represents a specific organism that existed during a known period.
On the other hand, index fossils are helpful for determining relative age. They are used to compare the age of the rock layer with other layers in a particular region. By looking at the sequence of index fossils found in different layers, scientists can establish an order of events. However, index fossils are not as specific in terms of determining an exact numerical age.
Therefore, in the context of determining the age of a rock, an ancient relative of a living organism would be more useful because it indicates a specific time period in which the rock was deposited, offering a more accurate dating method.
I really don't know enough about this topic to help you, but you can compare your answer to the information here:
http://www.nature.com/scitable/knowledge/library/dating-rocks-and-fossils-using-geologic-methods-107924044