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How do fossils help paleontologists study the history of life on Earth?
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Earth sciences
Geologist using a rock hammer to sample active pahoehoe lava for geochemical analysis on the Kilauea volcano, Hawaii, June 26, 2009.
Fossils are the primary source of information for understanding the history of life on Earth. Paleontologists and geologists use the fossil record—the collection of remains, impressions, and traces preserved in the Earth's crust—to study the past in several key ways:1
- Evolutionary History: By observing progressive morphological changes within animal groups over time, scientists can describe the evolution of those species and their adaptations to specific environments.21
- Geologic Dating: Fossils allow geologists to assign relative ages to sedimentary rock layers. Through the principle of faunal succession, specific index fossils help correlate rock strata across different geographic locations.13
- Environmental Reconstruction: The presence of certain organisms provides clues about ancient climates and ecosystems. For example, fossils of species that require warm, shallow water can indicate that a site was once a tropical marine environment, even if it is now located in a polar region.21
- Resource Exploration: Fossils are essential in identifying the stratigraphic position of fossil fuels, such as coal, oil, and natural gas.14