The Modern Mass Extinction
by Sarah Edmunds
There have been five major mass extinctions in geological history. The first occurred about 440 million years ago, when severe global cooling wiped out 25% of Earth's families, each of which may have contained thousands of species. The second mass extinction occurred about 370 million years ago, when 19% of families were lost. Plate tectonic movements and climate change caused the third mass extinction 245 million years ago, which destroyed 54 percent of families. Thirty-five million years later, a fourth mass extinction eliminated 23% of families. Sixty-five million years ago was the fifth and most famous mass extinction – the end of the dinosaurs. Today we are in the middle of what scientists believe to be the sixth mass extinction; this time, however, humans are to blame.
We cannot deny that extinction is happening right now. In fact, in the last 500 years, 844 species have died out, and this number only represents known species that have gone extinct. Even more remarkable is the number of species on Earth that are undiscovered – between five and thirty million – that may go extinct before we even learn of their existence. Of these, experts predict one species disappears every twenty minutes. That's three every hour, or roughly 30,000 every year. And humans are responsible.
Humans rely on nature to survive. Ecosystems provide food, natural resources, oxygen, and fertilizer for agriculture. Plants are used in medicines to keep people alive. Yet the success of one species only causes other species to become extinct more quickly. As humans use and abuse nature's resources, we harm the other organisms who share Earth with us. Humans build roads, clear forests, and pollute the air, and consequently, destroy habitats and decrease population sizes of affected species. Humans have also contributed to spreading of "alien species"-exotic invaders that prey on native species. An example of this is the European zebra mussel, which was accidentally transported to North America by seafaring. And let's not forget about the intentional, direct harm that humans cause: hunting, fishing, and poaching.
The sixth mass extinction began when humans began evolving, when the earliest hominids migrated and forced other species out of their habitats through ecological competition. The extinction of other animals accelerated ten thousand years ago, when humans figured out how to grow crops and no longer had to compete with other species for survival. Instead of relying on nature for food, humans were able to manipulate it to produce whatever they wanted. Humans were in complete control of their environment and did not have to follow the rules of the ecosystem, meaning they could overpopulate. The sixth mass extinction continued throughout the past two centuries with the industrial revolution, which meant more pollution, more production, and more people populating the Earth. It continues today as humans continue to produce and consume, pollute and destroy.
Conservationists argue that humans are ethically obligated to save endangered species. Not only did we cause their endangerment in the first place, but we also possess the intelligence to modify our behavior. But on the other hand, human beings are natural creatures and their evolution was a natural process. Why is extinction caused by human evolution any less acceptable than extinction caused by an asteroid colliding into the Earth? Should humans devolve back to a pre-agricultural state to conserve as many species as possible?
Or should we accept our fate - the world's fate - that the moment humans began evolving, all species were doomed? The human species can only become so powerful. Eventually, we will destroy so many species that out own survival is hindered. Humans seem to be at the top of the biological hierarchy, but as soon as the bottom levels are gone, those at the top must fall. It is probable that eventually humans will become extinct as well, and pave the way for a new species to dominate the earth several million years from now. But as for the modern extinction, we have the power to prolong our existence, and the existence of many other species. If we are to continue down this path of human supremacy and evolution, we have to accept the fact that species will continue to die out. But some conservation on our part can keep the world beautiful and biologically diverse for awhile.
