Paleontology
Paleontology or palaeontology is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geologic time, and assess the interactions between prehistoric organisms and their natural environment. While paleontological observations are known from at least the 6th century BC, the foundation of paleontology as a science dates back to the work of Georges Cuvier in 1796. Cuvier demonstrated evidence for the concept of extinction and how the life of the past was not necessarily the same as that of the present. The field developed rapidly over the course of the following decades, and the French word paléontologie was introduced for the study in 1822, which was derived from the Ancient Greek word for 'ancient' and words describing relatedness and a field of study. Further advances in the field accompanied the work of Charles Darwin who popularized the concept of evolution. Together, evolution and extinction can be understood as complementary processes that shaped the history of life.
Paleontology overlaps the most with the fields of geology and biology. It draws on technology and analysis of a wide range of sciences to apply them to the study of life and environments of the past, particularly for the subdisciplines of paleobiology and paleoecology that are analogous to biology and ecology. Paleontology also contributes to other sciences, being utilized for biostratigraphy to reconstruct the geologic time scale of Earth, or in studies on extinction to establish both external and internal 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 the increase in interdisciplinary studies. Several improvements in understanding have occurred from the introduction of theoretical analysis to paleontology in the 1950s and 1960s which led to the rise of more focused fields of paleontology that assess the changing geography and climate of Earth, the phylogenetic relationships between different species, and the analysis of how fossilization occurs and what biases can impact the quality of the fossil record.
Paleontology is also one of the most high profile of the sciences, comparable to astrophysics and global health in the amount of attention in mass media. Public attention to paleontology can be traced back to the mythologies of indigenous peoples of many continents and the interpretation of discovered fossils as the bones of dragons or giants. Prehistoric life is used as the inspiration for toys, television and film, computer games, and tourism, with the budgets for these public projects often exceeding the funding within the field of paleontology itself. This has led to exploitation and imperialism of fossils collected for institutions in Europe and North America, and also appeals to the public for sponsorships to the benefit of some areas of paleontology at the detriment of others.
Concept
Paleontology is the study of life of the past, characterized but not defined by the study and interpretation of fossils. It overlaps with the fields of geology and biology especially, but also with ecology, chemistry, physics and mathematics. Paleontology consists of both conceptual theorizing and focused scientific study. Traditionally, the sub-field of invertebrate paleontology has been closely tied to the study of geology, biostratigraphy, and historical geology, which have both commercial and academic drivers, whereas vertebrate paleontology has been more closely tied to biology with limited commercial applications. Both areas of study have broadened over time as a result of developing technology, but the "classical" requirements of fieldwork, laboratory preparation, and study of comparative anatomy remain core components of most sub-fields of paleontology. Paleontological study provides a direct source of information on the anatomy, physiology, ecology, and chronology of life on Earth, and the fossil record can be used to test hypotheses relevant to a range of scientific disciplines including other earth sciences and life sciences.The word paleontology or palaeontology is a compound word formed from the roots "paleo-", "onto-" and "-logy", equivalent to the French word paléontologie or the German word Paläontologie. The spelling paleontology is primarily used in North America, while the spelling palaeontology is preferred in the United Kingdom and was historic spelled as palæontology. Multiple different pronunciations can be found, including , , and . The root word "paleo-" is from the classical Latin or scientific Latin palaeo- and its predecessor Ancient Greek παλαιο- meaning "ancient" or "old", the root noun "onto-" is from the Ancient Greek ὀντ- meaning a sense of relatedness, and the root word "-logy" is from the French ‑logie which derives from the classical Latin ‑logia and the Ancient Greek ‑λογία and in context means a field of study.
Foundation
Paleontology includes the study of extinct animals and plants, including both direct observations about their remains and inferences about their behavior and how they interacted with their environment. From the recognition that fossils represented the remains of extinct organisms, paleontology became the zoology, botany, and biology of extinct organisms and therefore an important source for comparative anatomy. It was not always understood that paleontology is an evolutionary science, but over time, instances of evolution were recognized in the fossil record, and the two concepts have been closely linked ever since. The long span of geological time preserved in the fossil record allows very slow evolutionary changes to be observed, and the discovery of extinct organisms has allowed scientists to fill in gaps in the tree of life that cannot be understood through the study of extant organisms. The incorporation of a wider range of life sciences has allowed sub-disciplines like paleobiology and others to emerge.Fossils
Prior to the 19th century, the word "fossil" was used as a descriptive noun to characterize anything that had been dug out of the ground, including bones, stones, and gems. Early descriptions of what we now understand to be fossils described their appearances alongside and in the context of other minerals, crystals, and rocks. These early publications varied in contents of "fossils" across a wide spectrum of inorganic to organic appearances, including true fossils of differing preservation qualities, inorganic concretions, and structures with a resemblance to organisms. Over time the criteria for separating organic fossils from potentially organic or clearly inorganic materials brought about a change in the etymology of the word "fossil" itself, so accounts before the 19th century may not reflect the same use of the word fossil as modern paleontology. Both inorganic and organic fossils were illustrated in numerous books on the topic throughout the 16th century, with some attributing them to the work of God and other suggesting applications in construction or medicine. Fossils were not believed to have been organic, but instead to have exhibited the same kind of "growth" as crystals. Support for a possibly organic nature of fossils began in the 17th century, though it remained contentious as different quarries or strata yielded different fossils, which the scientists of the time did not have the context to explain. The fact that most fossils came from organisms that had never been observed alive anywhere in the world seemed to imply that these organisms were extinct, which was contrary to the belief of a perfect divine creation. Another compounding factor was that fossils of apparently marine animals were found in parts of the world that were well above sea-level. Some suggested that these fossils had accumulated in horizontal layers under the sea and that subsequent tectonic activity had displaced them from their original positions. As these observations were made over time, it was eventually understood that fossils could be used to make inferences about the history of life from their presence or absence in particular areas over time.The fossil record is the main tool used by scientists to study the history of life and assess the diversification of life over time. Very little is known about the origins of life and the oldest life forms, and this is likely a result of the poor quality of fossil preservation in older rocks. Older rocks preserve less information on average than those deposited closer to the present, and this effect is compounded across the billions of years that life is believed to have existed. Most fossils are made up of the hard parts of an organism that have been recrystallized by minerals, preserving bone, wood, or shells in a material than can be harder or denser than in life. While the hard parts are the most likely to fossilize, soft tissues can also leave impressions on sediment before they fully decompose, allowing non-mineralized parts of an organisms anatomy to be preserved. Even more rarely, a complete organism can be encased in sediment before decomposition, preserving it completely. While most fossils are body fossils, some fossils can also consist of traces of the behaviour or life of organisms. This can include preserved burrows, footprints or coprolites, which are grouped together and called trace fossils. However, only a small minority of all dead organisms will ever become fossils. Some things can destroy organisms before or even after fossilization, including scavengers, decomposers, or natural disasters, and fossils can even be destroyed after they are formed by taphonomic processes. Even if a fossil survives burial, it can still be destroyed by weathering if it is exposed and not collected. The habitat of an organism can also impact its chances of fossilization. Seafloors are more likely to fossilize than land, and rivers or lakes are more likely to fossilize than mountains or deserts. Fossilized teeth are very common, but are not always collected when they are found, and more complete fossils may be more likely to be collected, but they are generally rarer in absolute terms. Even after collection, fossils may not be studied for a long time. They may remain in museum storage in crates, be on display, or be otherwise unaccessible to scientists.