History Of Mass Extinction Essay

The number of wild animals on Earth has halved in the past 40 years . Creatures across the land, rivers, and the seas are destroyed as humans killed them for food in unsuitable numbers, while polluting or destroying their habitats.

The scale and pace of change is dramatic; for example, the extinction of species is occurring at around 100-fold pre-human rates4. The population sizes of vertebrate species have, on average, declined by half over the last 45 years5. More than 2.3 million km2 of primary forest has been felled since 20006. About

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

There have been five major mass extinction on earth triggered by a distinguishable event, but in The Sixth Extinction: An Unnatural History, Elizabeth Kolbert writes of the narrative of the sixth extinction caused directly by human impact. The book identifies the effects of human activity on how, over humans history on earth, the natural world has been affected. Every environmental impact stems into three basic groups of global problems to nature: Pollution, Habitat loss and Invasive Species. Kolbert explains that each impact can be traced back to one source, human industrial development. With each impact various types of life in the natural world are affected. Deforestation, urbanization, and sea level rise contribute to habitat loss worldwide. When humans began to travel they also brought invasive species and disease along with them; as boats only became bigger more and more invasive species travel. This reverse engineering of the planet species, brings new species that don’t have any natural predators, thus having an easier time driving native species out to endangerment or extinction. The different outcomes that come from human pollution is separated throughout the book, but the idea remains constant; with the development of human culture, pollution has drastically impacted a vast extent of species habitats and their environment.

Neanderthals and modern humans coexisted for well over 100,000 years.  Then suddenly Homo neandertalensis began to die out and surrender the earth to Homo sapiens.  Paleontologists and anthropologists have entertained several possibilities to the causes of this event: interbreeding among Neanderthals and humans, competition for natural resources, and Darwin’s theory of “survival of the fittest.”  What the real cause has been has plagued scientists for years. Now, due to an international research team from Germany, those possibilities have been even further deduced, making it easier to pinpoint the exact reason Homo neandertalensis became extinct.

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.

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

The biggest mystery surrounding the dinosaur is how did they die? For over 130 million years dinosaurs ruled the earth. Then 65 million years ago, at the end of the Cretaceous period, they died out.

Since before the industrial evolutions humans have been pumping green house gasses—carbon dioxide, water vapor, methane, nitrous oxide, and chlorofluorocarbons— into the atmosphere however, it wasn’t until recently that the amounts being produced are shoving the Earth into a sixth extinction. While the causes of this upcoming extinction are constantly debated on it has earned itself the name Holocene extinction. This name is derived from the theory that humans are the main contributors to this extinction. To investigate the cause Elizabeth Kolbert, and American journalist and professor at Williams College, took the world on a wild and saddening journey on the human contribution to this looming extinction in her novel, The Sixth Extinction; An Unnatural History. Not only does Kolbert’s book explain how humans have contributed to global warming and its effects on life on land but also ocean acidification and how life under the sea has changed over the years.

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

The health of the earth degrades with the destructive activity of human beings. A recent study by a group of scientists looked at twenty four different services that the earth’s ecosystems provide for humans, ecosystem services, and found that fifteen of them are in need of desperate help (Gazette 31 March 2005). These services are vital to the survival of both human and nonhuman life and include filtering water and providing nutrient rich soils and ocean waters. Many of the members of these various ecosystems are also decreasing in numbers. In a British survey of bird populations found that in the 200 birds of Britain tracked there was about a 54% population decrease between the 1968-1971 tacking period and the 1988-1991 tacking period. In two other surveys of 254 native plant species from the same area there was a decrease of about 28% during the past 40 years. Humans are pushing the sixth mass extinction (Gazette March 19, 2004).