Paleontology

Paleontology, also spelled palaeontology, is the scientific study of life in the past, mainly through fossils. Paleontologists use fossils to classify organisms, measure geologic time, and study how prehistoric organisms interacted with their natural environment.

Observations of fossils go back at least to the 6th century BC, but paleontology became a science through the work of Georges Cuvier in (/wiki/1796_in_paleontology). Cuvier showed evidence for extinction and that life in the past was not necessarily the same as life today. The field grew quickly in the following decades. In (/wiki/1822_in_paleontology), the French word paléontologie was introduced for the study. It came from the Ancient Greek word for 'ancient' and words describing relatedness and a field of study. Later advances came with Charles Darwin, who made the idea of evolution widely known. Evolution and extinction can be understood as complementary processes that shaped the history of life.

Paleontology overlaps most with geology and biology. It uses technology and analysis from many sciences, especially in paleobiology and paleoecology, which are similar to biology and ecology. It also helps other sciences. For example, biostratigraphy is used to reconstruct Earth's geologic time scale, and studies of extinction look for factors that can lead to the disappearance of a species. Much of the history of life is now better understood because of advances in paleontology and more interdisciplinary studies. Since theoretical analysis was introduced to paleontology in the 1950s and 1960s, more focused fields have grown up. These study how Earth's geography and climate have changed, the phylogenetic relationships between species, and how fossilization occurs and which biases can affect the quality of the fossil record.

Paleontology is also one of the most high-profile sciences, comparable to astrophysics and global health in the attention it receives in mass media. Public interest can be traced back to the mythologies of indigenous peoples on many continents, who interpreted discovered fossils as the bones of dragons or giants. Prehistoric life inspires toys, television and film, computer games, and tourism. The budgets for these public projects often exceed the funding within paleontology itself.

Concept

Paleontology (also spelled palaeontology) is the study of life in the past. It mostly works by studying and interpreting fossils. It overlaps with geology and biology especially, and also with ecology, chemistry, physics and mathematics. Paleontology includes both conceptual theorizing and focused scientific study. Invertebrate paleontology has long been closely linked to geology, biostratigraphy, and historical geology. Vertebrate paleontology has been more closely linked to biology. Both areas have grown as technology has improved, but fieldwork, laboratory preparation, and the study of comparative anatomy are still core parts of most sub-fields.

Paleontology gives direct information about the physiology, ecology, and chronology of life on Earth. Fossil evidence can also test ideas in many sciences, including other earth sciences and life sciences. The word comes from the roots "paleo-", "onto-" and "-logy". The root "paleo-" comes from classical Latin or scientific Latin and Ancient Greek, where it means "ancient" or "old".

Foundation

Main article: Fossil

Main article: Geologic time scale

Main article: Extinction

Main article: Evolution

Paleontology studies extinct animals and plants. Scientists look at their remains and make inferences about how they behaved and interacted with their environment. Once fossils were understood to be the remains of extinct organisms, paleontology became an important source for comparative anatomy. Paleontology is also an evolutionary science. The fossil record shows extant organisms that are no longer alive, which helps fill gaps in the tree of life, and the field has grown into areas such as paleobiology. Fossils became central to the study of Earth's history after Georges Cuvier and Charles Lyell showed that geology and the fossil record could explain past events. Scientists later created the geologic time scale to organize Earth's long history into named units. Extinction became understood as a key part of paleontology, and Charles Darwin helped explain how extinction and evolution work together.

Most fossils are hard parts of organisms, such as bones, wood, or shells, that have been changed by minerals over time. Only a small number of dead organisms ever become fossils, and many fossils are destroyed before scientists can study them. Older rocks hold less information, which is why very little is known about the origins of life. Paleontologists study mass extinctions and natural selection, an idea Darwin proposed that became central to the theory of evolution. Because fossils only show snapshots of the past, scientists use them carefully to understand how species changed. New fossil discoveries continue to fill gaps in our understanding of life's history.

History

Main article: History of paleontology

Cuvier is generally regarded as the first paleontologist, because he showed that fossils in stone were traces of living things that had gone extinct. People wrote about fossils long before him, going back to classical antiquity. The philosopher Xenophanes (6th century BCE) believed fossil shells came from life in the past, while Aristotle explained fossils as "vaporous exhalations." In the middle ages, Avicenna and Albert of Saxony refined Aristotle's idea into a theory of a petrifying liquid. Chinese naturalist Shen Kuo used petrified bamboo found in areas that were too dry for bamboo to suggest a theory of climate change. The Italian polymath Leonardo da Vinci argued in his unpublished notebooks that fossil shells came from living creatures. He studied sedimentation and is also credited as the founder of ichnology, which focuses on trace fossils. In the 17th century, Nicolas Steno and Robert Hooke continued this discussion, while Martin Lister completely rejected organic origins for fossils.

A major moment came when Georges Cuvier published evidence for extinction in 1796. He named Megatherium from bones found in Paraguay, and he showed that the mastodon belonged to species that were no longer alive. He also studied elephants and proved that mammoths from Siberia and Europe were different from their living relatives. Cuvier called the events that led to the disappearance of large animals, known as megafauna, "revolutions." In 1822, Henri Marie Ducrotay de Blainville, a former student of Cuvier, introduced the name "paléontologie" for the study of ancient life. Mary Anning and her family found marine reptiles such as Ichthyosaurus and Plesiosaurus near Lyme Regis. Later, Charles Darwin combined these ideas into his theory of evolution. Discoveries of theropods such as Compsognathus and Archaeopteryx supported the idea that birds evolved from other reptiles. For a long time paleontology was seen as part of geology, but in the second half of the 20th century it grew into paleobiology, which studies the biological side of fossils using tools such as phylogenetics, taphonomy, and paleoclimatology.

Applications

Main article: History of life

Main article: Mass extinction

Main article: Biostratigraphy

Main article: Evolutionary taxonomy

Paleontology both draws from and contributes to geology and biology, even though it was once seen as an easy science. By studying fossils, researchers can show how living things, rocks, and environments have changed over time, which helps us understand science today. Fossils have taught us much about the history of life. Before the Cambrian, very little was known, but discoveries of Ediacaran biota have shown life that ranged from tiny single-celled organisms to larger many-celled life. Fossils also show how birds gradually evolved from dinosaurs, and how whales changed from land animals into swimmers. Human evolution is also better understood, and the evolution of the human genus was likely in Africa. Mass extinctions happen quickly on the scale of geologic time. The Cretaceous-Paleogene extinction event is believed to have been caused by an asteroid impact, although its cause is still debated.

Fossils have been used to match up rock layers since at least the 18th century. Scientists use index fossils together with other measurements to work out geologic time, and the geologic time scale is based mainly on when different fossil groups appeared and disappeared.

The modern system of taxonomy began with Carl Linnaeus. Today, scientists often use phylogenetic methods to show how living things are related through evolutionary family trees. Because of this, the older Linnaean system has gradually fallen out of use.

Subdisciplines

Paleontology overlaps with many other sciences, and these overlaps form more specific fields. Its overlap with biology is called paleobiology, which studies topics such as evolution, extinction, and how organisms developed and lived. Other subdisciplines focus on particular groups of living things, such as invertebrates, paleobotany for plants, paleoalgology for algae, paleoentomology for insects, paleoichthyology for fish, paleomycology for fungi, paleomyrmecology for ants, paleornithology for birds, paleoprimatology for primates, and paleozoology for animals in general.

Other subdisciplines focus on specific subjects. Paleoanthropology studies the evolution of humans. Paleobiogeography uses fossils to study where different living things lived. Paleoclimatology studies ancient climates, and paleoecology reconstructs the lifestyles and ecosystems of ancient life. Paleohistology studies the hard tissues of fossils, while paleopathology studies ancient disease. Paleophysiology looks at how ancient life coped with its surroundings, and paleoichnology studies trace fossils, which show behavior such as footprints and burrows. Taphonomy is the study of how organisms become fossils and what happens to them between burial and discovery.

Cultural significance

See also: Cultural depictions of dinosaurs

Paleontology is one of the most high-profile sciences. Discoveries about dinosaurs or human evolution often appear in the mass media, and only astrophysics and global health get as much press attention. Prehistoric life inspires toys, television, films, computer games, and tourism attractions. Famous examples include the dinosaurs Tyrannosaurus, Triceratops, and Brontosaurus, early humans such as Homo floresiensis, and animals like sabre-toothed cats. Paleontology does not receive large amounts of money for research. In 2021, the American Museum of Natural History had an operating budget of $178 million, while the 2018 film Jurassic World: Fallen Kingdom cost $516.1 million. Public interest may come from the mystery, the huge scale of time, the size of some animals, and the similarities between myths of dragons and giants and the fossils of ancient animals. The public focus also means that most attention goes to dinosaurs and a few regions, while other parts of the field get less notice. Marketing paleontology to children can make the field seem "childish."

Long before paleontology was a science, many indigenous peoples explained fossils through myths. Traditional Chinese medicine used Pleistocene mammal fossils as "dragon bones" or "dragon teeth." European and North American Christians interpreted some fossils as Nephilim, mentioned in the Book of Genesis. In the 1850s, paleoartistic reconstructions of ancient ecosystems included the Crystal Palace Dinosaurs sculptures, created under the direction of Benjamin Waterhouse Hawkins. In the 1860s, Hawkins also built the first free-standing dinosaur skeleton, Hadrosaurus, at the Academy of Natural Sciences in Philadelphia. The Bone Wars between American paleontologists Othniel Charles Marsh and Edward Drinker Cope in the late 19th century drew media attention and later became a popular story in novels, comics, books, and even a musical. Later, a second American dinosaur rush began at the start of the 20th century. Fossils from Africa, Asia, and South America were taken by North American and European institutions, linking paleontology with imperialism. Books and films also shaped public interest, starting with stone-age Europeans in 1890s stories and The Lost World by Arthur Conan Doyle, published in (/wiki/1912_in_paleontology). Interest declined during the Cold War but returned in the 1970s, when The Dinosaur Heresies by Robert Bakker and papers by John Ostrom described dinosaurs as active animals, a period called the "dinosaur renaissance." The biggest rise in public interest came in the 1990s with the novel Jurassic Park by Michael Crichton and the Steven Spielberg film. Today, paleontology also reaches the public through blogs and podcasts. Paleontology has contributed to tourism in places such as the Jurassic Coast and the Isle of Wight in southern England, Peace River (Florida), and Dinosaur National Monument, which spans Colorado and Utah.