geologist finds fossils of a lizard-like dinosaur and a fern-like tree in layers that are 1.0 m and 1.5 m deep. However, in a layer that is 2.0 m deep, he finds fossils of bony fish and shellfish.
Which explains?
1.
The continent shifted to a polar region.
2.
The ancient land area was invaded by a sea. **
3.
The ancient sea dried up and became land.
4.
An asteroid hit the area, causing the dinosaur to become extinct.
I disagree. The evidence of a sea is older than the trees and dinosaurs.
So it would be the ancient sea dried up and became land. I was just backwards, lol @Ms. Sue
You're right.
The most plausible explanation for the fossils found in different layers is option 2, which states that the ancient land area was invaded by a sea.
To understand this explanation, geologists use the principle of superposition, which states that in undisturbed layers of rock, the younger layers are deposited on top of older layers.
In this scenario, the geologist found fossils of a lizard-like dinosaur and a fern-like tree in the deepest layers, which indicates that these organisms lived during a time when the land area existed. The layers that are 1.0 m and 1.5 m deep contain fossils of different organisms, suggesting a change in the environment.
When the geologist finds fossils of bony fish and shellfish in the layer that is 2.0 m deep, it implies that the environment changed again, and a sea invaded the ancient land area. This change in fossil composition suggests that the ancient land area was submerged under water, providing a suitable habitat for marine organisms.
Therefore, the presence of different types of fossils in different layers can be explained by the ancient land area being invaded by a sea, as described in option 2.