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Since the 1980s, decreases in amphibian populations, including population decline and localized mass extinctions, have been observed in locations all over the world. This type of biodiversity loss is known as one of the most critical threats to global biodiversity.
Mass extinctions are characterized by the loss of at least 75% of species within a geologically short period of time (i.e., less than 2 million years). [18] [51] The Holocene extinction is also known as the "sixth extinction", as it is possibly the sixth mass extinction event, after the Ordovician–Silurian extinction events, the Late Devonian extinction, the Permian–Triassic extinction ...
In a landmark paper published in 1982, Jack Sepkoski and David M. Raup identified five particular geological intervals with excessive diversity loss. [2] They were originally identified as outliers on a general trend of decreasing extinction rates during the Phanerozoic, [3] but as more stringent statistical tests have been applied to the accumulating data, it has been established that in the ...
A 2018 Science Magazine paper estimated that at 1.5 °C (2.7 °F), 2 °C (3.6 °F) and 3.2 °C (5.8 °F), over half of climatically determined geographic range would be lost by 6%, 18% and ~49% of insect species, with this loss corresponding to >20% likelihood of extinction over the next 10–100 years according to the IUCN criteria.
The Bivalvia would comprise about 14% of the total and the other five classes less than 2% of the living molluscs. [21] In 2009, Chapman estimated the number of described living mollusc species at 85,000. [3] Haszprunar in 2001 estimated about 93,000 named species, [22] which include 23% of all named marine organisms. [23]
Lampreys form a superclass containing 38 known extant species of jawless fish. [3] The adult lamprey is characterized by a toothed, funnel-like sucking mouth. Although they are well known for boring into the flesh of other fish to suck their blood , [ 4 ] only 18 species of lampreys are actually parasitic. [ 5 ]
An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. [1]
Agnatha (/ ˈ æ ɡ n ə θ ə, æ ɡ ˈ n eɪ θ ə /; [3] from Ancient Greek ἀ-(a-) 'without' and γνάθος (gnáthos) 'jaws') is a paraphyletic infraphylum [4] of non-gnathostome vertebrates, or jawless fish, in the phylum Chordata, subphylum Vertebrata, consisting of both living (cyclostomes) and extinct (conodonts, anaspids, and ostracoderms, among others).