Cretaceous-Tertiary Mass Extinction

“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…”

The scientists believe that the herbivores ran out of plants, and trees and so all of the herbivores died and after all of the herbivores died, all of the Carnivores died as well. Another theory is that a big asteroid hit the Earth, and the asteroid caused a global extinction.. The final theory that the scientists thought of happening was a disease. Disease may of happened from one dinosaur getting sick and then it just passed on from dinosaur to dinosaur.

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.

Dinosaurs ruled the earth for over 65 million years and thankfully for the human race, they became extinct. Ultimately, only a major catastrophe could completely wipe out an entire species, let alone an entity of dinosaurs and the debacle on the causes of dinosaur extinction have flooded the minds of paleontologists for centuries. Geologist and zoologist Stephen Jay Gould published “Sex, Drugs, Disasters, and the Extinction of Dinosaurs,” to compare scientific and speculative causes of dinosaur decimation. Personally, I found this passage very informational and enjoyed reading it. Gould provides three theories that capture the reader’s curiosity, allowing room for pondering in one’s mind.

8. The periods in which there were mass extinctions are Permian – volcanic eruptions which spewed lava and put CO2 into the air which warmed the climate an estimated 6 degrees Celsius. The resulting of oxygen deficiency. And Cretaceous – asteroid or comet

In Stephen Jay Gould’s “Sex, Drugs, Disasters, and the Extinction of Dinosaurs”, Gould investigates three possible theories hypothesizing the reason behind the extinction of dinosaurs. The first theory suggests that dinosaurs became extinct due to a rise in temperature, which caused sperm to die, leading to the sterilization of male dinosaurs. The second hypothesis offer that many dinosaurs consumed bitter plants that contained psychoactive agents which their lives could not detoxify out of their systems. The last speculation about the dinosaur’s extinction is that a large cloud of dust formed in the atmosphere after an asteroid hit Earth’s surface. This dust cloud blocked out the sunlight, causing temperatures to drop and made photosynthesis impossible. Gould uses these three theories to lead to his central claim that science isn’t just about making fascinating claims, but should have a well developed hypothesis.

The Permian mass extinction, that struck about 250 million years ago, caused a mass extinction of reef and shallow water communities. Groups that lived on the seafloor and filtered organic material from the water for nourishment suffered the greatest extinction. Those include corals, shelled in-vertebrates, and a variety of sea lilies. Others marine groups includes trilobites, zooplankton and snails. Even though these species died in the water, living organisms on land were not much better off. Terrestrial vertebrates and insects both experienced a big loss in each of their groups. Also suffering a big loss was the insect family due to the lack of plant life and food. Seventy Eight percent of reptiles became extinct and sixty seven percent of the amphibian family became extinct during this time period.

The K-Pg event, the day life on earth was wiped out, is one of the most notorious extinctions in the history of the world. From jawed fish, to plants, to crocodyliforms (10 species’ fossils have been found, 5 of which are extinct), even a species of pterosaurs, life was extinguished; however, what happened to the creatures? What truly killed the dinosaurs? There are many theories but some ideas are downright insane. Some older ideas consist of comets dusting the Earth with a poisonous gas, or the caterpillars eating the plants, starving the herbivores; then the carnivores because they had nothing to eat but each other. Another theory is that the continental shift built up mountains, and over time those mountains changed the climate and the

The Late Devonian mass extinction is one the ‘Big Five’ mass extinction in history of earth which occurred 374.5Ma ago. This extinction event saw at least 70% of species perished; where main victim of this extinction event were the major reef builders, stromotopoids, rugose and tabulate corals (McGHee 2012). Causes of this mass extinction event during the late Devonian gathered a wide variety of debate throughout the years whereby researchers researched substantial theories supported by evidences. The few

The end of this period happens to be one of the most famous extinctions. This was the extinction when all of the dinosaurs died out, except for the birds. About 65.5 million years ago, nearly all large vertebrates and many tropical invertebrates became extinct. So, what caused this mass extinction? Scientists still do not have a definite answer, but they do have two hypotheses’. These hypothesis are that an extraterrestrial impact, such as an asteroid or comet, or a massive bout of volcanism put an end to it. Either of these things would’ve choked the skies with debris, which would’ve blocked the suns energy. The block in the suns area would’ve caused a lot of harm to photosynthesis, therefore many animals would not have a food source to supply them with the necessary nutrients. By the end of the Cretaceous period, all large and small ruling reptiles, except the crocodile became extinct. Whatever the explanation to this extinction was, it resulted in the Cretaceous Period

Ever since the history of Earth has been studied using fossil records, extinctions have always been the object of fascination and interest, particularly the mass extinctions that occurred throughout Earth's history. A mass extinction can be caused by disruptive global environmental changes, where large numbers of species have become extinct (Urry et al. 2008). There have been five major extinctions documented based on fossil records over the past 500 million years, but the Cretaceous (KT boundary extinction – a name that meant it began the Tertiary era) extinction caught a lot of

There have been five well known extinctions on this earth. The one most well known is the mass extinction that ended the dinosaurs. Mass extinction is often described as the elimination of a large number of species in a short period of time. Despite what many think, the elimination of species is almost commonplace at this point. The Earth is currently in the middle of a sixth mass extinction, and it’s been caused by the human race.

Over 98% of all organisms that have lived on Earth are now extinct. A mass extinction event occurs when a large number of species die out within a small time frame (relative to the age of Earth). Mass extinctions are intensively studied for both cause and effect, as there is usually room for debate regarding catalysts that precede the extinction and the massive influx of new biological species that follows. There have been five major mass extinctions, dubbed the “Big Five,” that have wiped out at least 50% of the species living at those times. The most well known mass extinction of the Big Five, with the decimation of every species of non-avian dinosaur, is the Cretaceous-Paleogene

Nobody can really say what actually eliminated the species, although everyone has their very own idea. Asteroid impact, atmospheric changes (hot to cold), catastrophic eruptions and astronomical events (supernovas etc.). Some have ventured that early mammal inhabitation slowly “pushed” the dinosaurs to extinction. The most favored theory in the scientific field is that of the meteor impact. As always though, knowing when is part of discovering how and why.

Rapid climate change also ends up on the suspect list of possible dinosaur extinction events. During the latter part of the Cretaceous Period continents broke up causing volcanoes to erupt and fill the sky with gas and ash resulting in a drastic climate change (“Dinosaurs Climate Change and Biodiversity”). The shifting of continents changed the Earth’s landscape, altering weather patterns and overall climate (“Dinosaur Extinction Theories”). Also, over a long period of time, climate gradually changed. Ocean habits changed, temperatures grew much more extreme causing scorching summers and frigid winters (Norell, Dingus, and Gaffney). Radical temperature changes like these led to a green-house effect, making life for the dinosaurs a lot