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Research from 2007 and 2018 indicated that the reemergence of varieties of chytrid fungi may account for a substantial fraction of the overall decline. [ 17 ] [ 18 ] [ 19 ] A number of diseases have been related to mass die-offs or declines in populations of amphibians, including "red-leg" disease ( Aeromonas hydrophila ), Ranavirus (family ...
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 ...
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).
The World Wildlife Fund’s Living Planet Report 2022 found that wildlife populations declined by an average 69% since 1970. [1] [2] [3]The Living Planet Index (LPI) is an indicator of the state of global biological diversity, based on trends in vertebrate populations of species from around the world.
The phylum is typically divided into 7 or 8 taxonomic classes, [8] of which two are entirely extinct. Cephalopod molluscs, such as squid , cuttlefish , and octopuses , are among the most neurologically advanced of all invertebrates —and either the giant squid or the colossal squid is the largest known extant invertebrate species.
The world ocean covers an area of 3.618 × 10 8 km 2 with a mean depth of 3682 m, resulting in an estimated volume of 1.332 × 10 9 km 3. [17] If all of Earth's crustal surface was at the same elevation as a smooth sphere, the depth of the resulting world ocean would be about 2.7 kilometres (1.7 mi).
[165] [166] Chickens, cattle, sheep, pigs, and other animals are raised as livestock for meat across the world. [ 161 ] [ 167 ] [ 168 ] Animal fibres such as wool and silk are used to make textiles, while animal sinews have been used as lashings and bindings, and leather is widely used to make shoes and other items.
The list below largely follows Darrel Frost's Amphibian Species of the World (ASW), Version 5.5 (31 January 2011). Another classification, which largely follows Frost, but deviates from it in part is the one of AmphibiaWeb , which is run by the California Academy of Sciences and several of universities.