Extinction events Extinction events The Cambrian-Ordovician extinction event occurred approximately 488 million years ago. It was the first major extinction event and eliminated many brachiopods, conodonts, and severely reduced the number of trilobite species. The Cambrian-Ordovician event ended the Cambrian period, and created the Ordovician period in the Paleozoic era. ...more on Wikipedia about "Cambrian-Ordovician extinction events"
The Cretaceous-Tertiary (K-T or KT) extinction event, also known as the KT boundary, was a period of massive extinction of species, about 65.5 million years ago. It corresponds to the end of the Cretaceous Period and the beginning of the Tertiary Period. (K is the traditional abbreviation for the Cretaceous period. Cretaceous comes from the Latin for chalk, creta. The K comes from the German word for chalk kreide, or possibly Greek kreta. The K is used so as to avoid confusion with the Carboniferous period which uses the letter C.) ...more on Wikipedia about "Cretaceous-Tertiary extinction event"
An extinction event (also extinction-level event, ELE) occurs when a large number of species die out in a relatively short period of time. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine invertebrates and vertebrates every million years. ...more on Wikipedia about "Extinction event"
The Holocene extinction event is a name customarily given to the widespread, ongoing extinction of species occurring in the modern Holocene epoch. The extinctions vary from mammoths to Dodos, to countless species in the rainforest dying every year. Because some believe the rate of this extinction event is comparable to the "Big Five" mass extinctions, it is also known as the Sixth Extinction, though the actual numbers of extinct species are not yet similar to the major mass extinctions of the geologic past. ...more on Wikipedia about "Holocene extinction event"
The Late Devonian extinction was one of five major extinction events in the history of the Earth's biota. A major extinction occurred at the boundary that marks the beginning of the last phase of the Devonian period, the Famennian faunal stage, (the Frasnian-Famennian boundary), about 364 million years ago, when all the fossil agnathan fishes suddenly disappeared. A second strong pulse closed the Devonian period. ...more on Wikipedia about "Late Devonian extinction"
A megatsunami is an informal term used by popular media and popular science for very large tsunami-like waves significantly beyond the size reached by tsunamis (typically around 10 meters). For this reason, there is no scientific definition of a megatsunami. Informally, the term generally refers to waves beyond the norm for tsunamis, ranging from over 40 metres (131 feet) to giants over 100 metres (328 feet) tall. Note that megatsunamis often reach higher than their wave height when they meet land, as the water often floods upwards from the force of impact. ...more on Wikipedia about "Megatsunami"
The Ordovician-Silurian extinction event, which may have been composed of several closely spaced events, was the second largest of the five major extinction events in Earth's history in terms of percentage of genera that went extinct. The only larger one was the Permian-Triassic extinction event. ...more on Wikipedia about "Ordovician-Silurian extinction events"
The Permian-Triassic (P-T or PT) extinction event, sometimes informally called the Great Dying, was an extinction event that occurred approximately 252 million years ago ( mya), forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, with about 90 percent of all marine species and 70 percent of terrestrial vertebrate species going extinct. For some time after the event, fungal species were the dominant form of terrestrial life. ...more on Wikipedia about "Permian-Triassic extinction event"
The Shiva crater is a hypothetized impact crater located in the Indian Ocean west of India. It has been suggested that it formed around 65 million years ago, the same time as a number of other impacts that are recorded in the K-T boundary. ...more on Wikipedia about "Shiva crater"
Alexander Tollmann's bolide, proposed by Kristen-Tollmann and Tollmann (1994), is a hypothesis presented by Austrian professor of geology Dr. Alexander Tollmann, suggesting that one or several bolides ( asteroids or comets) struck the Earth at 7640 BCE (±200), with a much smaller one at 3150 BCE (±200). If true, this hypothesis explains early holocene extinctions and possibly legends of the Universal Deluge (Kristen-Tollmann and Tollmann 1994). ...more on Wikipedia about "Tollmann's hypothetical bolide"
The Triassic-Jurassic extinction event occured 200 million years ago and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. 20% of all marine families and all large Crurotarsi (non-dinosaurian archosaurs), some remaining therapsids, and many of the large amphibians were wiped out. At least half of the species on Earth went extinct. This event opened an ecological niche allowing the dinosaurs to assume the dominant roles in the Jurassic period. This event happened in less than 10,000 years and occured just before Pangea started to break apart. ...more on Wikipedia about "Triassic-Jurassic extinction event"
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