Permo-Triassic Mass Extinction Essay

“A minority disputes this theory, arguing that other events-such as volcanic eruptions, sea-level changes or a series of impacts-were to blame for the spectacular loss of species that occurred at the transition between the Cretaceous and Tertiary periods…”

Was it the confluence of events outlined in this review (including the prevailing global climate, volcanism), or are some of these factors secondary? For example, we have little idea of the mass of methane hydrates in the Late Permian ocean floor. These and many other questions will need to be addressed before we fully resolve the cause of the end-Permian mass extinction. However, there is a growing realisation that flood basalt volcanism has the potential to be the primary trigger for mass extinctions, rather than meteorite impacts or other external

Nobody knows for sure exactly how the dinosaurs became extinct. However scientists have speculated for decades about possible events that caused the dinosaurs to die out. Possibilities range from asteroids, to volcanoes, to climate changes. One of the more popular or well-known extinction theories involves the belief that an asteroid struck the Earth, causing devastating effects, and triggering mass extinctions around the end of the Cretaceous period.

Further more you can begin to wonder what could have been the explanation for these land and marine species to become extinct. Their have been many explanations and hypothesis to try to explain why these land and marine species became extinct including the belief of plate tectonic shifts. This particular explanation goes along with the belief that shifts in plate tectonics ( which includes the shift in the earths outer most layer) have moved certain species that are more heavily adapted to the sun and shifted them to colder regions and vice versa (Smith). In the text Smith explains how the particular hypothesis used is known as being intrinsic (meaning a natural; and gradual, taking some time to occur (few millions years). The evidence of this particular theory actually being the cause of the cretaceous mass extinction is placed on the sea levels and fossil record. The rise in seas levels have made million year old fossils appear above thousands of feet of present day sea level, which would give the hint that ocean levels fell drastically as the cretaceous period came to an end (Jones). Not only that , but the fossil record shows that dinosaur species didn't dramatically become extinct but gradually declining millions of years before the cretaceous mass extinction actually happened (

The fifth, and one of the largest and most well known extinctions in Earths history was the Cretaceous period, where many species, including the dinosaurs, pterosaurs, and large marine reptiles, disappeared. This period was widely known as the K-T period, K being the traditional abbreviation for the Cretaceous Period derived from the German name Kreidezeit, and T being the abbreviation for the Tertiary Period (a historical term for the period of time now covered by the Paleogene and Neogene periods). It was a relatively warm climate and had high global sea levels. The oceans and seas were populated with now extinct marine reptiles, ammonites and rudists, and the land by dinosaurs. At the same time, new groups of mammals and birds as well as flowering plants appeared. The early part of the Cretaceous showed a cooling trend that had been

The end-Triassic or Triassic-Jurassic extinction event occurred around 200 million years ago is and thought by numerous have helped dinosaurs to be the dominant species on earth for 135 million years. It additionally finished life for generally 50% of all species that were available around then. Until this event, mammal like animals known as therapsids were much more than the ancestors of the dinosaurs, known as archosaurs. The dinosaurs survived better compared to the early proto-vertebrates, and this extinction event may have altogether tipped it to support them clarifies #########. Of the Big Five, the Triassic-Jurassic extinction event has the least number of current researches. Its cause stays under debate,

The Cretaceous-Tertiary extinction or K-T extinction, which marks the Late Cretaceous, is a massive and large-scale extinction of animal and plant species that occurred over a short period of time 66 million years ago.

The Triassic-Jurassic extinction occurred about 210 million years ago, killing about 80 percent of all living species (“End-Triassic Extinction”). Most species were hit hard, but there were no major full-on extinctions. Still, cephalopods, sponges, corals, reptiles, and pollen and spore producing plants were hit hard. The dinosaurs, however, were lucky and survived the extinction intact. This allowed them to reign supreme for the next geological epoch (“End-Triassic Extinction”). During the time of the Triassic-Jurassic extinction, Pangea was in the process of breaking apart. This caused major volcanic activity to occur, one of the prevailing theories as to what caused this extinction (“End-Triassic Extinction”). Like during the Permian-Triassic

It is now generally believed that the K–Pg extinction was triggered by a massive comet or asteroid impact 66 million years ago and its catastrophic effects on the global environment, including a lingering impact winter that made it impossible for plants and plankton to carry out photosynthesis. The fact

The Cambrian Explosion, which happened 541 million years ago, marks a date when a huge number of complex, multi-celled organisms began developing all over the world. This burst of different species eventually led to the development of most well known creatures today. Scientists used the huge number of new fossils to determine a date through radioactive or carbon-40 dating. However, like most good things this huge outburst had to come to an end. A huge event nearing the end of the Paleozoic Era is the Permian Extinction. 251 million years ago marks the end of the Paleozoic Era with a bang: wiping out 90 percent of all earth's organisms. Theorized to be cause by acidic rain and volcanic fumes, the Permian Extinction is known by some scientists as the largest murder mystery ever. Through an even larger increase in fossils than before, scientists yet again determined the date of these fossils by using radioactive or carbon-40 dating. As the Paleozoic Era is nearing its end the next era is right on the

Mass extinction of the Dinosaurs the most dramatic extinction in the history of the Earth. ( national geographic, 2015 ) The dinosaur extinction could have been sudden or gradual depending on the cause. Scientists have thoroughly researched and finally found two major options, the asteroid impact theory and the volcanic theory, that have many similar qualities, but on the other hand are very different. These two theories could have possibly caused the extinction many years ago.

(1987), the Precambrian-Cambrian boundary is located in-between Ediacaran Fauna, which is found somewhere between 620-700 million years ago and trilobites, such as the fallotospid group. This creates a period ranging between 30-50 million years in which we can define the Precambrian-Cambrian boundary, making it difficult to determine an accurate timeframe (Morris, 1987). Biomineralization is seen as another key indicator of the Precambrian-Cambrian boundary, this has recently been identified as occurring around 570 million years ago. Kerr (1993) addresses the recent understanding of the Cambrian explosion, which is believed to have occurred simultaneously with the presence of hard skeletal parts. Globally, it is seen that Ediacaran Fauna has been well preserved despite being soft bodied. This has given a good understanding on metazoan evolution (Morris, 1987). Evolution rates of metazoan started to become evaluated with higher precision geochronology. Ultimately, this resulted in a better understanding of Ediacaran Fauna, leading to the belief that the lack of Ediacaran Fauna during the Cambrian, compared to its presence in the Precambrian was due to its continuous evolution, rather than the sudden disappearance due to an event (Bowring and Erwin,

Although data for terrestrial species is not as complete as for marine species, there is evidence to show that terrestrial life was also severely impacted. The End Permian Extinction is the only one known to have caused the mass extinction of insects; 8 out of the 27 insect orders known to have persisted during the early Phanerozoic eon did not survive past the Permian-Triassic

In the surface ocean, the residence time for foraminiferal tests near photic zone can be considered as few weeks as the average life span of foraminifera varies between 1-4 weeks (Be et al., 1977; Be et al., 1981, Nigam et al., 2003). Within the seawater column below photic zone the foraminiferal tests can be in contact with seawater for ~1-2 weeks (for test >150 μm) depending on the test size and weight, and the average post-mortem settling velocity (Berger and Piper, 1972; Takahashi and Be, 1984). Finally, after settling on the seafloor, the foraminiferal tests can reside near-sediment water

Cnidarians (or coelenterates), including sea anemones, jellyfish, and corals, are built mostly of sheets of cells, and they exploit the large surface area of the