The History of Earth's Mass Extinctions Essay

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The History of Earth's Mass Extinctions

The four billion year history of earth has witnessed five mass extinctions, and some scientists believe that we are on the verge of the sixth.1[1] If we are in the midst of the next mass extinction, we are in the very early stages of an evolving, and escalating process. The most recent, or fifth mass of the extinctions occurred 65 million years ago at the boundary between the Cretaceous and Tertiary periods. Images of an asteroid colliding with the planet, decimating the dinosaur population have been in circulation since the early 80’s.2[2] Being the most recent mass extinction, thousands of scientists around the world have investigated it, and elementary school children are familiar with
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Experts have put together various theories about previous mass extinctions and their findings have led some to believe that we are in the early stages of the sixth. One finding that has worried scientists throughout the world is the rate at which species of plants and animals have been going extinct. Previous research had discovered that the number of species of birds around the world has been on a steady decline for some time.6[6] While this detection did raise some red flags, it was not evidence that the next mass extinction had been launched.

While birds are abundant both in sheer population and number of species scientists needed to discover the decline of more than one selection of animals. More than half of the detected species of animals on earth are insects.7[7] If scientists wanted substantial, tangible evidence that there was a widespread decrease in animal populations and worldwide decrease in biodiversity, researching insects was the way to go. The results across the board were not the least encouraging.

The populations of butterflies in Britain were at the forefront of the researchers’ findings. Overall, 71 percent of the butterfly populations have decreased in numbers and 3.4 percent of
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