Paleoendemism along with

neoendemism Neoendemism is one of two sub-categories of endemism, the ecological state of a species being unique to a defined geographic location. Specifically, neoendemic species are those that have recently arisen, through divergence and reproductive isola ...

is a possible subcategory of

endemism Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

. Paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have recently arisen, such as through divergence and reproductive isolation or through hybridization and

polyploidy Polyploidy is a condition in which the biological cell, cells of an organism have more than one pair of (Homologous chromosome, homologous) chromosomes. Most species whose cells have Cell nucleus, nuclei (eukaryotes) are diploid, meaning they ha ...

in plants.

Etymology

The first part of the word, paleo, comes from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word ''palaiós, meaning "ancient".'' The second part of the word, ''endemism'' is from

New Latin New Latin (also called Neo-Latin or Modern Latin) is the revival of Literary Latin used in original, scholarly, and scientific works since about 1500. Modern scholarly and technical nomenclature, such as in zoological and botanical taxonomy ...

''endēmicus'', from Greek ενδήμος, ''endēmos'', "native". ''Endēmos'' is formed of ''en'' meaning "in", and ''dēmos'' meaning "the people".

Causes

Changes in climate are thought to be the driving force in creating paleoendemic species, generally due to habitat loss. Regions where the climate has remained relatively stable form refugia which are more likely to be endemic hotspots today. This applies to both neoendemism and paleoendemism. However, paleoendemism differs as it does not require additional factors such as barriers and ecological opportunities as it does not rely on

adaptive radiation In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic int ...

like neoendemism does. It instead relies on the instability of other regions' climate, which may limit the range of a species to a more stable region, thus turning that species paleoendemic. Limited ability for dispersal is also important in the creation of endemic species. The two terms can essentially be defined as "cradles" of new species (neoendemism), or "museums" of old species (paleoendemism).

Examples

It is not always clear whether a particular species is paleoendemic or neoendemic. Ginkgos are a paleoendemic genus. From the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

to the mid- Cenozoic, these trees could be found throughout the world. However, today, they can only be found in China in the wild.

Paleoendemism on islands

Islands as harbors for endemic species are explained by the theory of

island biogeography Insular biogeography or island biogeography is a field within biogeography that examines the factors that affect the species richness and diversification of isolated natural communities. The theory was originally developed to explain the pattern of ...

.{{Cite book, url=https://press.princeton.edu/titles/7051.html, title=The Theory of Island Biogeography, publisher=Princeton University Press, access-date=2019-03-06, isbn=9780691088365, date=2001-03-18, last1=MacArthur, first1=Robert H., last2=Wilson, first2=Edward O. However, in order to be considered a paleoendemic on an island, the species must have had a widespread distribution previously, thus eliminating newly formed islands as potential refuges of paleo-endemics.

References

Endemism

Etymology

Causes

Examples

Paleoendemism on islands

See also

References