Paleontology

Paleontology is the study of prehistoric plant and animal life. It is made possible by fossils: the remains and traces of once-living organisms that have become preserved in rock. Fossils enable paleontology to not only measure the shapes and diversity of past life but also to determine the nature of ancient environments, reconstruct paleoecologies, and observe the patterns of evolutionary change. To achieve this, paleontology integrates extensively with other earth, biological, and physical sciences, and more recently with mathematics, planetology, and climatology. Paleontological research has made significant contributions to understanding geological and biological processes, such as global tectonics and organic evolution. Important for human nature, this has enabled us to observe our own evolutionary heritage and relationships with other species through the fossil record. Amid growing concern for the natural health of earth, paleontologists provide valuable data for the study of climate change and extinctions.

Most organic remains and traces of plants and animals have a common fate:to be decomposed and broken down to rejoin the earth from which they originated. But this process is not perfect, and. under certain conditions. the remains and traces of life become trapped and incorporated into rock, becoming preserved for up to billions of years. These remnants are known as fossils, and they are the primary objects of study in paleontology, a word derived from the Greek, meaning “study of ancient life.”

Human beings have long been curious about and attracted to the fossil remains of plants and animals, as evidenced by artifacts of fossilized tree resin, shells, and wood found in camps dating back tens of thousands of years. This valuation of fossils as simply objects that are visually appealing would continue for some time. Even during the birth and development of geology as a science, humankind interpreted fossils essentially as strange-looking stones and considered them to be similar in origin to minerals, crystals, and other rocks. The realization that fossils were once living organisms was a profound development that shifted some emphasis away from geological theory and toward a more biological approach.

Fossils are not restricted to the bones of vertebrates. They also may form from the body parts of invertebrates, plants, and microscopic life, collectively called body fossils. In addition, the footprints, burrows, borings, and other relics of the behavior of an organism during its lifetime may become fossilized and are known as trace or ichnofossils. A challenge of paleontology is to deal with the incompleteness of the fossil record due to our planet's limited environments being [Page 1806]able to maintain the conditions suitable to bury and fossilize an organism's remains over time. Not all organisms have the same potential for preservation. The process of fossilization can be arduous, and organisms with hard body parts and robust traces will be preferentially preserved over soft-bodied organisms. These factors mean that not all organisms will leave a fossil record, and, in fact, fossilization is exceptionally rare for any life form. There will be considerable gaps between forms. The lack of abundant fossils in the space between ancestral and descendant species was one of the strongest arguments railed against Charles Darwin's theory of organic evolution. But even the incomplete fossil record provides abundant data at significant points of life's history to answer specific paleontological questions and test evolutionary theories.

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