gady-i-płazy: Lazarus taxon

Evidence: 100 • authority: 72

In paleontology, a Lazarus taxon (plural taxa) is a taxon that disappears for one or more periods from the fossil record, only to appear again either in later fossil records, or as actual living organisms, and often in isolated, obscure, or otherwise very specialized habitats. Likewise in conservation biology and ecology, it can refer to species or populations that were mistakenly thought to be extinct, and are rediscovered to be still living. The term Lazarus taxon was coined by Karl W. Flessa and David Jablonski in 1983 and was then expanded by Jablonski in 1986. Paul Wignall and Michael Benton defined Lazarus taxa as, "At times of biotic crisis many taxa go extinct, but others only tempo…

Evidence: 63 • authority: 88

Lazarus taxa and fossil abundance at times of biotic crisis. Mass extinctions are often followed by intervals in which taxa disappear from the fossil record only to reappear again later. This ‘Lazarus effect’ is often attributed to a poor-quality fossil record or migration to refuges. Testing these alternatives, with examples from the end Permian and late Triassic extinctions, reveals that there is no link with the abundance of fossiliferous sites and the proportion of Lazarus taxa nor are missing taxa encountered in potential refuges. Therefore, the abundance of Lazarus taxa in the aftermath of these extinctions is probably a reflection of the extreme rarity of organisms at this time.

Evidence: 47 • authority: 80

Discussion on Lazarus taxa and fossil abundance at times of biotic crisis <i>Journal,</i> Vol. 156, 1999, pp. 453–456

Evidence: 42 • authority: 72

The Triassic–Jurassic (Tr-J) extinction event, often called the Triassic–Jurassic mass extinction (TJME) or end-Triassic extinction, marks the boundary between the Triassic and Jurassic periods, 201.4 million years ago. It represents one of five major extinction events during the Phanerozoic, profoundly affecting life on land and in the oceans. In the seas, about 23–34% of marine genera disappeared; corals, bivalves, brachiopods, bryozoans, and radiolarians suffered severe losses of diversity and conodonts were completely wiped out, while marine vertebrates, gastropods, and benthic foraminifera were relatively unaffected. On land, all archosauromorph reptiles other than crocodylomorphs, din…

Evidence: 32 • authority: 72

An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms. It occurs when the rate of extinction increases with respect to the background extinction rate and the rate of speciation. Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem from disagreement as to what constitutes a "major" extinction event, and the data chosen to measure past diversity.

Evidence: — • authority: 88

What are Lazarus taxa?. Abstract The many definitions and interpretations associated with the ‘Lazarus effect’ have considerably confused this notion. While several authors regard the Lazarus effect as the temporary disappearance of taxa from the fossil record in any given time interval, many others consider the Lazarus effect as a pattern restricted to mass extinction episodes. The adequacy of the fossil record is the key for interpreting the Lazarus pattern: either Lazarus taxa reflect the incompleteness of the fossil record (the ‘stratigraphic alternative’), or they illustrate genuine extinction‐linked phenomena (the ‘biological alternative’). The latter option includes two traditional h…

Evidence: — • authority: 72

A ghost lineage is a hypothesized ancestor in a species lineage that has left no fossil evidence, but can still be inferred to exist or have existed because of gaps in the fossil record or genomic evidence. The process of determining a ghost lineage relies on fossilized evidence before and after the hypothetical existence of the lineage and extrapolating relationships between organisms based on phylogenetic analysis. Ghost lineages assume unseen diversity in the fossil record and serve as predictions for what the fossil record could eventually yield; these hypotheses can be tested by unearthing new fossils or running phylogenetic analyses. Ghost lineages and Lazarus taxa are related concept…

Evidence: — • authority: 72

A living fossil is a term for an extant taxon that phenotypically resembles related species known only from the fossil record, though scientifically the term is deprecated and avoided. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossils commonly are of species-poor lineages, but they need not be. While the body plan of a living fossil remains superficially similar, it is never the same species as the remote relatives it resembles, because genetic drift would inevitably change its chromosomal structure. Living fossils exhibit stasis (also called "bradytely") over geologically long time scales. Popular literature…

Evidence: — • authority: 72

Neontology is a part of biology that, in contrast to paleontology, studies and deals with living (or, more generally, recent) organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example: The Indian elephant (Elephas maximus) is an extant species, and the woolly mammoth (Mammuthus primigenius) is an extinct species. The moose (Alces alces) is an extant species, and the Irish elk (Megaloceros giganteus) is an extinct species. In the group of molluscs known as the cephalopods, as of 1987 there were approximately 600 extant species and 7,500 extinct species. A taxon can b…

Evidence: — • authority: 72

Extinction is the termination of a species via the death of its last member. A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. As a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. Over five billion species are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, possibly many times more if prokaryotes a…

Evidence: — • authority: 92

Ocean warming affected faunal dynamics of benthic invertebrate assemblages across the Toarcian Oceanic Anoxic Event in the Iberian Basin (Spain).. The Toarcian Oceanic Anoxic Event (TOAE; Early Jurassic, ca. 182 Ma ago) represents one of the major environmental disturbances of the Mesozoic and is associated with global warming, widespread anoxia, and a severe perturbation of the global carbon cycle. Warming-related dysoxia-anoxia has long been considered the main cause of elevated marine extinction rates, although extinctions have been recorded also in environments without evidence for deoxygenation. We addressed the role of warming and disturbance of the carbon cycle in an oxygenated habit…

Evidence: — • authority: 92

How predictable are mass extinction events?. Many modern extinction drivers are shared with past mass extinction events, such as rapid climate warming, habitat loss, pollution and invasive species. This commonality presents a key question: can the extinction risk of species during past mass extinction events inform our predictions for a modern biodiversity crisis? To investigate if it is possible to establish which species were more likely to go extinct during mass extinctions, we applied a functional trait-based model of extinction risk using a machine learning algorithm to datasets of marine fossils for the end-Permian, end-Triassic and end-Cretaceous mass extinctions. Extinction selectiv…