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Extinction occurs at an uneven rate. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine animals every million years. [c] The Oxygen Catastrophe, which occurred around 2.45 billion years ago in the Paleoproterozoic, is plausible as
[82] [83] Studies of the size of the ichnotaxon Naktodemasis bowni, produced by either cicada nymphs or beetle larvae, over the course of the K-Pg transition show that the Lilliput effect occurred in terrestrial invertebrates thanks to the extinction event. [84] The extinction event produced major changes in Paleogene insect communities.
Dresbachian extinction event: 502 Ma: End-Botomian extinction event: 517 Ma: Precambrian: End-Ediacaran extinction: 542 Ma: Anoxic event [45] Great Oxygenation Event: 2400 Ma: Rising oxygen levels in the atmosphere due to the development of photosynthesis as well as possible Snowball Earth event. (see: Huronian glaciation.)
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites
An ecological cascade effect is a series of secondary extinctions that are triggered by the primary extinction of a key species in an ecosystem.Secondary extinctions are likely to occur when the threatened species are: dependent on a few specific food sources, mutualistic (dependent on the key species in some way), or forced to coexist with an invasive species that is introduced to the ecosystem.
Coextinction refers to the loss of a species due to the extinction of another; for example, the extinction of parasitic insects following the loss of their hosts. Coextinction can also occur when a species loses its pollinator, or to predators in a food chain who lose their prey. "Species coextinction is a manifestation of one of the ...
Scientists are using a UC Santa Cruz greenhouse to recreate the mass extinction that wiped out the dinosaurs. They want to learn why some species survived when so many did not.
This was compared against climate reconstructions for the last 90,000 years. The researchers found correlations of human spread and species extinction indicating that the human impact was the main cause of the extinction, while climate change exacerbated the frequency of extinctions. The study, however, found an apparently low extinction rate ...