Interesting Facts About Fossils
Fossils contain the remains of often bizarre-looking plants and modern species' prehistoric relatives. Yet fossils show us much more than what life forms looked like millions of years ago. These permanent records from the distant past also show us the way these organisms lived through fossilized footprints, trackways, feeding marks, nests and burrows. Scientists can associate some of these fossils with organisms still on the Earth today.
Other People Are Reading
-
Environmental Indicators
-
The work of Miriam Katz, a professor of Earth and environmental sciences at Rensselaer Polytechnic Institute, suggests fossils contain evidence of environmental changes. Her study of sand grain-sized deep-sea fossils traces up to 250 million years of the Earth's climate changes. These little fossils are known as foraminifera and can be examined to determine previous sea levels, temperatures and ocean conditions. By studying foraminifera, Katz paints a portrait of "how, when and why our climate has changed so drastically over geologic history." Her work offers a science-based opportunity to track modern climate conditions. Drawing such parallels between the past and the present may enhance the future of environmental science.
Evolutionary Evidence
-
As scientists examine older and older layers of rocks, they are actually examining layers of time and planetary history. This process, also known as "fossil succession," helps scientists identify the ancestors of different species over a span of geological time. One example of how fossil succession relates to evolutionary theory is in the discovery of the oldest known fossil with feathers, the Archaeopteryx. Close examination of the fossil led some scientists to identify a definitive link between birds and reptiles. This discovery supports the idea that birds are the descendants of reptiles. Such fossil evidence upholds the Darwinian idea that "living beings have changed through time and older species are ancestors of younger ones," according to the U.S. Geological Survey.
-
Earth's Crust Movement
-
Fossils will move as the Earth's crust moves. For instance, ancient upward land lifts may contain sea-floor marine shell fossils. Index fossils appearing at elevations other than where they were first deposited are a sign of a previous earth fractures, even if a fault is no visible. A fossil's distance from the ocean floor or presence in the Himalayas alerts scientists to sites where major Earth movements have taken place.
Ancient Geography
-
Fossils assist scientists in determining if the world's continents were once connected. The distribution of certain fossils creates an unexplainable presence of animals and plants outside of their commonly known natural habitats. Since fossils also support the theory of plate tectonics, the most widely accepted explanation is continental drift: The idea of migration across land bridges is obsolete, and the traveling of plant seeds across vast oceans is impossible.
Age Indicators
-
Fossils do not tell scientists the precise year they were on the Earth. They do offer them a time range to specify when the species was common, however. Making correlations between fossil finds known as "index fossils" help this process. Index fossils must be from a species that spread around the world rapidly. Only those that existed for a short interval of time can qualify as an index fossil. Key index fossils include ancient pollen and formaninifera. Formaninifera are among the oldest fossils in existence.
-
References
- Photo Credit little fish fossil image by Andrew Kazmierski from Fotolia.com
