Sixth Mass Spieces Extinction Essay

The asteroid impact extinction theory began in 1980 with Luis and Walter Alvarez, a father and son team. They theorized that an asteroid struck the Earth at the close of the Cretaceous period, causing devastating effects and mass

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

Some of the ways we have extinguished species include, climate change, air pollution causing ocean acidification, accidental imports of plants animals or fungi, fragmenting and destroying habitats, and poaching and killing animals for resources. I agree with Kolbert. We humans are making the planet difficult for other species to live in. One of the ways that we are killing species is accidental or intentional imports of plants and animals. Kolbert talked about the Pangea.

The Cretaceous – Tertiary mass extinction, commonly referred to as the KT extinction, occurred 65 million years ago. As the most recant extinction event it is more easily studied as more evidence has been preserved than for the earlier extinctions. This extinction is the most commonly known, as it is the extinction of the dinosaurs, but the smallest scale mass extinction with only 76% of species dying out.

In a summary, Kolbert explains the extinctions of a variety of different major animal species that became extinct. She also explains that if trends in the environment continue that the biggest extinction in history will occur soon. If global warming, deforestation, and glaciers continue to melt she says that more and more species will continue to become extinct. She explains how humans need to be more conservative and careful with what they’re doing to prevent extinction.

Although many people seem to have an understanding or guess as to how the dinosaurs and similar species may have become extinct around this time period, their are many theories out there suggesting otherwise. So in light of that my question is , What mite have been the primary cause or ( causes ) of the Cretaceous-Tertiary Mass extinction ?. This particular question interested me primarily on the fact that it not only took away many species from earth, but also the many different theories that associate with this mass extinction. Just as quick as these species were taken from the earth , their origin for their demise is just as important.

The dinosaurs appeared after the greatest mass extinction event occurred. This is known as the Permian-Triassic extinction. It has been estimated to have occurred around two hundred and fifty million years ago. (6) It is also known as the Great Dying with over ninety percent of species dying off, leaving the Earth essentially a wasteland. It led to the extinction of “57% of all families, 83% of all genera and 90% to 96% of all species. 53% of marine families, 84% of marine genera, about 96% of all marine species and an estimated 70% of land species, including insects.”(7) By the late-Permian, global temperatures were very hot, with them being the highest ever on the planet.

The Cretaceous mass extinction is the most well-known case of meteorite impact on the earth, but it certainly is not the only one. It is merely the most well-known. Due to the impact, debris entered earth's atmosphere and caused the plant life of the time to die off due to the lack of sunlight to survive. This made food much more scarce for the species that were dominant at the time. The competition was simply too much for them, and as the plant life died out, so did the herbivores and then the carnivores died out as well. Not only the land was impacted, however, the sea life was affected heavily by this impact as well. The lack of sunlight caused the oceans to become colder, causing the habitats of many marine animals to be drastically altered

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,

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.

Habitat destruction, deforestation, ozone depletion, global warming, and poaching. These actions and ecological happenings are creating a world where animals are going extinct at rapid rates. Our world is on the brink of what scientists believe is the sixth mass extinction. Unlike the five previous mass extinction, the latest one killing a majority of the dinosaurs, the main causes for this current extinction are anthropogenic reasons, not natural events.

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.

They say as mammals continued to evolve, they drove the dinosaurs into extinction (“What Killed the Dinosaurs”). “Not only did mammals likely compete with dinosaurs for resources, many species survived the end-Cretaceous extinction and subsequently came to dominate Earth.” (“What Killed the Dinosaurs?”). This is primarily because the early mammals were a lot smaller than the mammals that exist today. “Some of the world's earliest mammals were the multituberculates, a group of small rodent like animals that first emerged on Earth about 165 million years ago.” (Welsh, Jennifer). Scientists predict that any mass extinction event that caused animals to go extinct affected larger animals than it did the smaller animals, such as mammals ("Dinosaurs Became Extinct 'due to Laying Eggs'"). Mammals remained small for almost 100 million years, while they out competed small and baby dinosaurs for food, shelter and resources until they were extinct. Once the dinosaurs were out of the way mammals were able to evolve and grow large in size like the mammals that exist today today (LiveScience). Fossil evidence sheds some light on this theory as well. Fossils of mammals believed to date back to about eighty five million years ago show that mammals began to change rapidly and grow. “This matches up with other mammal groups, including recently discovered species from the Late Cretaceous (between 100 million and 65 million years ago) showing highly specialized