Ancient animal and plant remains that turned to stone record the past.
Fossils are the remains of living organisms or the evidence of their activity that have been buried in sediment and preserved, says Webster's New World Collegiate Dictionary. Paleontologists study fossils to learn when various types of life forms appeared and what their development, existence and extinctions tell us about the effects of changing conditions on Earth. Using isotope pairs with long half-lives, radiometric dating provides a means to accurately determine the age of individual fossils, says Action Bioscience.
Environmental Information
Fossils reveal information about the climate and other environmental characteristics of the time and location in which they were formed. Comparing early fossils to later ones and against the present provides evidence of environmental and climate change over millions of years. As an example, the Petrified Forest National Park in Arizona stands as evidence that this desert once received enough rain to support the growth of large trees, says the National Park Service. This long scientific record is vital to studies about the source of current global warming trends. Fossil records also express the impact of catastrophic events on living organisms, such as the sudden extinction of dinosaurs 65 million years ago after a large meteor landed in the Gulf of Mexico.
Geological Information
Fossils provide valuable clues to geologists searching for natural resources. The presence of specific types and amounts of plant pollen and spore fossils helps geologists date deposits of coal and confirm their connection, indicating the type of coal likely to be present, says the U.S. Geological Survey.
Fossils also play a vital role in developing and supporting theories of continental drift and plate tectonics. Mesosaurus fossils, for example, are found in both Africa and South America. This animal existed only in shallow, fresh-water environments, indicating the two land areas were joined when it existed during the late Paleozoic Era. Marine-life fossils, such as those of ammonites, are found in abundance at an elevation of 12,000 feet in the vicinity of the Himalayan Mountains; such findings influence the understanding of geologic processes too slow to be observed.
Evolutionary Information
Younger rocks lie atop older rocks, and any fossils they contain occur in a similar, universal and predictable order. The earliest known fossils, dated to 3.5 billion years ago, consist of bacteria, then algae and microscopic plankton. Scientific data gathered from the 1800s to the present indicate that living organisms have become more complex as time has passed. Paleontologists who study the structures of past living organisms note similarities, mutations and gradual changes, for example, from the earliest version of the equine species to modern horses. They find evidence that dolphin, whale and porpoise families descended from a land animal. However, a strictly linear evolutionary theory does not explain many fossils from the Vendian Period 560 million years ago, which scientists have been unable to categorize at even the most basic level.
Tags: living organisms, evidence that, have been, Information Fossils, million years, National Park
