Question

Part 2: Reading "Steno and the Shark"

Read the "Steno and the Shark" article to learn about how fossils in rock layers have helped
scientists understand Earth's history. Annotate the article as you read and answer the question
below.
1. How can scientists use fossils in rock layers as evidence that one event happened earlier than
another event?
ook at the events in your Sorting Tool activity and at the Geologic Time Scale diagram from
cle. In what period did the first fish appear?

Answer 1

Fossils in rock layers provide evidence of the chronological sequence of events in Earth's history by indicating the relative ages of the fossils and rock layers. For example, if a fish fossil is found in a lower layer and a mammal fossil is found in a higher layer, it suggests that the fish appeared earlier than the mammal.

Step-by-step explanation:

Fossils in rock layers can help scientists understand the order in which events occurred because the position of fossils in the rock can indicate the relative ages of the fossils and the rock layers they are found in. If a fossil is found in a deeper layer of rock, it is typically older than a fossil found in a shallower layer. By comparing the fossils in different rock layers, scientists can determine which events occurred earlier or later in Earth's history.

For example, if a fossil of a fish is found in a lower rock layer and a fossil of a mammal is found in a higher rock layer, it can be inferred that the fish appeared earlier than the mammal. The different ages of the fossils in these rock layers serve as evidence of the chronological sequence of events in Earth's history.

Learn more about Using fossils in rock layers to understand Earth's history