They provide information into the past, helping complete the story of evolution. In order for fossils to “tell” us the story of life, they must be dated. Then they can help scientists reconstruct how life changed over time. Fossils can be dated in two different ways: relative dating and absolute dating (Figure below).

How does the fossil record help date rocks?

So, often layers of volcanic rocks above and below the layers containing fossils can be dated to provide a date range for the fossil containing rocks. The atoms in some chemical elements have different forms, called isotopes. These isotopes break down at a constant rate over time through radioactive decay.

What does the fossil record tell us about rocks?

Fossils are the remains or traces of ancient life that are usually buried in rocks. Examples include bones, teeth, shells, leaf impressions, nests, and footprints. This evidence reveals what our planet was like long ago. Fossils also show how animals changed over time and how they are related to one another.

How do fossils contribute to the dating of rock layers?

Fossils above a specific layer are inferred to be younger than that layer, and those below are older, in line with the law of superposition, a key scientific principle of stratigraphy. Dating of the fossils contributes to a clearer timeline of evolutionary history.

What is the importance of the fossil record?

The fossil record helps paleontologists, archaeologists, and geologists place important events and species in the appropriate geologic era. It is based on the Law of Superposition which states that in undisturbed rock sequences the bottom layers are older than the top layers.

What Cannot be determined from the fossil record?

The fossil record cannot accurately determine when one species becomes another species. However, two hypotheses regarding speciation also exist. Phyletic speciation suggests that abrupt mutations in a few regulatory genes occur after a species has existed for a long period of time.

What is an example of fossil record?

Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.

Is the fossil record reliable?

Since then, fossils have been considered among the most important evidence for biological evolution,” Hannisdal explains. However, in his book on the origin of species, Darwin argued that the fossil record was far too incomplete to give a reliable picture of evolution.