How are extinct organisms classified and named?

Extinct organisms are classified and named based on the Linnaean system of taxonomy, using fossil evidence and comparative anatomy.

The classification and naming of extinct organisms is a complex process that involves a combination of paleontology, taxonomy, and sometimes, genetics. The primary method of classification is the Linnaean system, named after the Swedish botanist Carl Linnaeus. This system categorises organisms into a hierarchy of taxa, starting from the broadest (Kingdom) to the most specific (Species). The same system is used for both extinct and extant (currently living) organisms.

The first step in classifying an extinct organism is the collection and examination of fossil evidence. Fossils are the preserved remains or traces of organisms that lived in the past. They can include bones, shells, exoskeletons, stone imprints of animals or microbes, and traces of hair or skin. Paleontologists, scientists who study fossils, use these remains to determine the physical characteristics of the extinct organism.

Once the physical characteristics have been determined, the extinct organism can be compared to both extinct and extant organisms. This comparative anatomy allows scientists to determine the likely evolutionary relationships between the extinct organism and other organisms. For example, if an extinct organism has similar bone structures to a certain group of extant organisms, it may be classified in the same group.

The final step in the process is the naming of the extinct organism. This is done using binomial nomenclature, another part of the Linnaean system. The organism is given a two-part name: the first part is the genus, and the second part is the species. This name is often derived from Latin or Greek, and may describe a characteristic of the organism, or honour a person or place.

In some cases, genetic analysis may also be used in the classification of extinct organisms. If DNA can be extracted from the fossil, it can be sequenced and compared to the DNA of extant organisms. This can provide further evidence of the extinct organism's evolutionary relationships. However, this method is only possible if the fossil is not too old, as DNA degrades over time.