Approximately 250 million years ago, the earth underwent the most catastrophic extinction event in its entire history. The mass extinction occurred on the Permian-Triassic border on the geological timescale, and is appropriately nicknamed, “The Great Dying”. It has resulted in the most extinction occurrences, expressed in a %, than any of the other mass extinctions in geological time, as seen in FIGURE 1. The Permian Extinction created a huge setback for Earth’s fauna and its diversity. During the short duration of this event, the earth lost 90-96% of all species (Stanley, 2016). This extinction event occurred due to multiple mechanisms within a mere 1-million-year period, causing intense and uninhabitable living conditions in both the Earth’s …show more content…
This supercontinent formed when two large landmasses collided due to the workings of plate tectonics. During these geological settings, Earth had large regions of shallow seas creating great marine biodiversity. However, the merging of Gondwana and Laurasia reduced the total length of coastal areas. These settings, allowed life to flourish and diversify, but concentrated organisms in the shallow water along the coasts. This deepened the risk of an extinction if these specific areas on Earth’s surface were to be targeted.
The Great Dying is an occurrence caused by multiple mechanisms which weakened a range of ecosystems, making them susceptible to further damage. These different mechanisms build up over time, causing maximum destruction across large regions. The Permian Extinction resulted from a combination of sea-level changes, volcanic activity, alterations of ocean chemistry and asteroid impacts. The outcome of losing over 75% of species, classifying it as a mass extinction, only occurs through the specific timing and order of these
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The coverage of continental crust from pole to pole, as seen in FIGURE 1, affected the ocean currents and decreased the circulation of water. This “unmixed” water created long-term deep sea anoxia, meaning there is little to no oxygen available to support most life forms. This oxygen-poor environment and a lack of ventilation resulted in the deposit of black shales on the ocean floor. Ocean acidification also incurred with water becoming high in CO2 and of low pH. This caused the selective extinction of calcifying organisms which had thrived since the start of the Paleozoic era, such as the trilobite! In addition to these deadly alterations to the Permian ocean, there were high concentrations of hydrogen sulfide creating a place for sulfur reducing bacteria to flourish. The change to the Panthalassa Ocean’s chemistry proved lethal to marine life and its diversity, and killed off species known for surviving harsh living conditions in the
In this paper Martin is arguing that late quaternary or near time extinctions where caused by human activity or as he calls it “overkill”. Martin recognizes that there have been many forces that have triggered extinctions in the planet on the past but disagrees with the idea that near time extinctions where caused by some commonly believed causes like climate change, disease or nutrient shortage. He argues that the arrival of humans to different continents, islands and the subsequent excessive hunting, the introduction of diseases and other competitors and predators was the cause of extinction of a great number of species “As our species spread to various continents we wiped out their large
The question of what caused the extinction of megafauna during the Late Pleistocene period is one that archaeologists have struggled to answer for decades, but why should it matter? Discovering with certainty the cause of megafaunal extinction would simultaneously prove or disprove any of the proposed implications of each existing theory regarding this massive extinction.
The Permian-Triassic Extinction is a mass extinction that occurred between the Permian and Triassic geologic time periods approximately 250 million years ago; it is the deadliest of all extinctions that have occurred on Earth. In addition, during the Permian-Triassic extinction the continents of today existed as one supercontinent known as Pangaea. This was the first time in history where continental or land mass exceeded that of the ocean. This was also before dinosaurs of the Triassic period roamed Earth, during this time animals such as the therapsids, and Synapsids such as the Pelycosaurs, insects and amphibians also occupied Earth. Fauna that existed during the Permian period includes Gymnosperms, or seed producing plants such as the Conifers. Other animals that existed during this time include marine life such as brachiopods (clams), bryozoans (coral-like skeletons), bony fish and sharks, as well as crinoids (sea urchin like creatures). According to National Geographic, about 90 percent of all the animals and fauna of this period perished, the marine life was hit the hardest wi...
Throughout Earth’s history there have been many changes. These changes have consisted of temperature fluctuations, atmospheric differentiations, extinctions of various plant and animal life, etc. Over time everything seems to have evolved in some way form or fashion. However, the Permian Era extinction was different from all the rest. This extinction affected every form of life, but especially the marine life. Researchers have stated that 93-97% of all Earths species went extinct during this period of time. This essay will explain how a once blossoming progressive era turned into Earths most catastrophic event.
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There are several theories about how the Cambrian Explosion started. There were major changes in marine environments and chemistry from the late Precambrian into the Cambrian, and these also may have impacted the rise of mineralized skeletons among previously soft-bodied organisms. One theory as to what happened is that oxygen in the atmosphere, with the contribution of photosy...
The most significant event of the Cretaceous era came at its end. Nearly 65 million years ago, the second most severe mass extinction in earth’s history occurred. This resulted in the loss of around 80% of species living at the time. Though nowhere near as severe as the end-Permian mass extinction, the end-Cretaceous extinction is the most well known mass extinction event. This is due to the violent event that caused it the extinction, as well as the chapter of earth’s history that it closed: the Dinosaurs. The Cretaceous Event ( often shortened to K-T event) Of the animals that were killed off were the flying reptiles (pterosaurs) and the last few mosasaurs and plesiosaurs, both early marine reptiles. Many mollusks and species of microscopic plankton were killed. Terrestrial plants suffered mass extinction as well. Almost 60% of terrestrial plants were lost. This led to high extinction rates among insect populations, especially insects that were highly specialized to feed on just a few types of plants had it the worst. It took approximately 9 million years for the global insect populations to recover from the Cretaceous extinction. Immediately after the extinction, the earth saw an explosion of short term species who respond well to fire, or other external disturbance. Evidence of the catastrophe comes from a thin rock layer deposited worldwide just after the impact. It is dominated by fossil plants whose descendants recover quickly after fires of other disturbances, such as Fire Weed in Alaska. The causes of the Cretaceous extinction are still being debated by paleontologists. Scientists agree that the main cause of the extinction was a...
of species due to a variety of causes. Included is out competition, depletion of resources
Several mass extinctions have occurred during the Earth’s history. The Cretaceous – Tertiary Boundary (K-T) Extinction caused the loss of at least three-quarters of all species known at that time including the dinosaurs. The cause of this mass extinction is a controversial subject among scientists but the fossil evidence of it’s occurrence is abundant.
Earth has gone through five fully major extinctions before. We currently are in the process of Earth’s sixth mass extinction. This mass extinction is closely related in severity to the extinction of the dinosaurs. Earth’s extinctions are broken into three different areas. The first area was the large number of animals caught by hunter-gathers. The discovery of agriculture led to the second area of extinction, wildlife habitats. These wildlife habitats were destroyed due to humans starting to stay in one area.
Almost 23% of all families, 48% of all genera (20% of marine families and 55% of marine genera) and 70% to 75% of all species went extinct (Beaz). Although the cause of this mass extinction is debatable, many speculate that global warming was the killer. Because Pangea was breaking up into Laurasia and Gondwanaland, there was widespread volcanic activity caused by the rifting, increasing atmospheric carbon dioxide. The massive release of this greenhouse gas increased global air temperatures and resulted in acidified oceans along with rising sea levels. If this is the case, the life in the ocean would have died at a significant rate. Many families of brachiopods, gastropods, bivalves, and marine reptiles became extinct (Rafferty). An important trace fossil known as the phylloceratid ammonoid was able to survive, and they gave rise to the explosive radiation of cephalopods later in the Jurassic Period, as well as evolved into many different forms during the later Cretaceous (End Triassic Extinction). This extinction event ranks fourth in severity of the five major extinction events over geologic history
Extinction of Dinosaurs Many different theories exist as to why the dinosaurs went extinct. We know for sure most dinosaurs died around 65 million years ago. The majority of scientists agree on a number of theories as to what brought the end of the dinosaurs. The most popular theory is that an asteroid ended the reign of the dinosaurs. Another theory, massive climate change in the pre-historic atmosphere, caused all the dinosaurs to die.
Biodiversity loss can lead to extinction, and hurt human life. It is our responsibility to take care of the environment. We bring in machines that harm the environment and destroy animal life. We need to limit ourselves on how much land and resources we consume. There are major issues that are causing species to become extinct and hurt our way of life and other animals do to the change in food chain.
Because the CO2 levels are rising, the ice caps are melting and many more animals can become extinct. When pangea started splitting, there was a lot of volcanic activity, which cause the death of many dinosaurs. A meteor also hit earth and the mass extinction of many land and marine animals happened. There have been five mass extinctions in Earth’s history. The worst one wiped out ninety-six percent of marine life and seventy percent of land organisms. This took millions of years to recover.
The Earth is far and away the most biodiverse planet in our solar system, with about 8.7 million more unique species than the other 8 planets (UNEP). However, the Earth’s commanding lead is shrinking; not because the other planets are increasing biodiversity, but because Earth’s is decreasing. According to the World Wildlife Fund, we as a planet are losing 1,000 to 10,000 more species than the natural rate. Since the total number of species is hard to pin down, this can mean anywhere from 200 to 10,000 species going extinct per year (World Wildlife Fund). This obscenely high extinction rate is dangerous not just to ecosystems directly affected by the loss, but also creates a domino effect that circles around the globe and up and down the food