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About 17% of all families, 50% of all genera [6] and 75% of all species became extinct. [2] In the seas all the ammonites, plesiosaurs and mosasaurs disappeared and the percentage of sessile animals was reduced to about 33%. All non-avian dinosaurs became extinct during that time. [20]
As long as species have been evolving, species have been going extinct. It is estimated that over 99.9% of all species that ever lived are extinct. The average lifespan of a species is 1–10 million years, [35] although this varies widely between taxa. A variety of causes can contribute directly or indirectly to the extinction of a species or ...
In the seas, about 23–34% of marine genera disappeared. [1] [2] On land, all archosauromorph reptiles other than crocodylomorphs (the lineage leading to modern crocodilians), dinosaurs, and pterosaurs (flying reptiles) became extinct; some of the groups that died out were previously abundant, such as aetosaurs, phytosaurs, and rauisuchids. [3]
This page features lists of species and organisms that have become extinct. The reasons for extinction range from natural occurrences, such as shifts in the Earth's ecosystem or natural disasters, to human influences on nature by the overuse of natural resources, hunting and destruction of natural habitats.
But many marine species—estimates range between 178,000 and 10 million oceanic species—remain to be described. [102] It is therefore likely that a number of rare species (not seen for decades in the wild) have already disappeared or are on the brink of extinction, unnoticed. [104]
Even the reduction observed in species diversity (of 50%) may be mostly due to taphonomic processes. [151] [44] However, a massive rearrangement of ecosystems does occur, with plant abundances and distributions changing profoundly and all the forests virtually disappearing.
Some reasons these species go extinct are from habitat loss, overharvesting, pollution, invasive species, and climate change. Invertebrates make up most of Earth's biodiversity which is why they do not go extinct as fast as other species. Marine Invertebrates: These species' average lifespan is 5–10 million years.
Within cartilaginous fish, approximately 7 out of the 41 families of neoselachians (modern sharks, skates, and rays) disappeared after this event and batoids (skates and rays) lost nearly all the identifiable species, while more than 90% of teleost fish (bony fish) families survived. [86] [87]