Today, the planet is home to about ten million different types of organisms. This number is impressive, but if you add to it all the species that have existed on the planet before, the total is five billion! It turns out that ninety-nine percent of the creatures are already extinct. And many species continue to disappear, adding to the list of extinct forever. Many scientists believe that we are living in a period of incredibly rapid extinction. Such periods have occurred only five times in the last half a billion years.
Mass extinction
Scientists call the global decline in the number of species diversity in a short time mass extinction. People are the cause of this situation. Too many animals killed by hunters, too many fish caught, destruction of habitats and destruction of the ecosystem - all this pushes the species over a tragic line. People have changed the planet so much that, according to some geologists, a new era has begun in the history of the Earth, which can be called the Anthropocene.
In 2100, it is estimated that half of all currently existing species will disappear. Due to the fact that we live directly in such an era, it is relatively easy for scientists to study the reasons leading to such a situation. But how to explain what led to similar disasters in the past? For example, why are mammoths extinct? For the answer, you need to turn to archaeologists, paleontologists, geologists and other scientists - they are the ones who have evidence of what is happening in the distant past.
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Inconsistent data
The problem with studying the past is that different scientists cannot always come to a common point of view. Even if we are talking about the very last case of disappearance. In addition to the five largest mass extinctions of species, there were also less significant episodes. One of such cases occurred several tens of thousands of years ago. It is sometimes called the case of the extinction of megafauna, because at that time it was mainly large animals with a weight of more than forty-four kilograms that disappeared.
The reason for this remains a mystery. There is very little evidence, so scientists are forced to argue over each and try to figure out how to interpret it in the best way. To complicate matters further, in some parts of the world, the process of extinction was much slower than in others.
Climate change
One of the most popular versions of the explanation is climate change. The ice age was ending on the planet and the period of extinction began. The temperature rose by six degrees Celsius. Large animals were more affected by this change than small ones, because they cannot lose body heat as quickly as small ones. In addition, in the process, the weather was constantly changing, the conditions were either wet or very dry. This spurred the extinction of large animals. Ice Age mammals had a dense fur cover, so it was extremely difficult for them to adapt to such changes.
The hunter hypothesis and other theories
Another hypothesis about how mammoths and other large animals became extinct is the assumption of hunting. It arose at the end of the nineteenth century, when it was established that humans lived simultaneously with mammoths. Nevertheless, it was confirmed that the extinction of animals in Eurasia lasted too long - hunting cannot be the cause of such a process. As a result, a disagreement arose between scientists on the basis of determining the causes of extinction. Moreover, there are other assumptions. Some believe that it is due to fatal diseases that were carried by migratory people or animals.
Perhaps the theory about hunting is only partially true - for the territories of New Zealand and Australia. The thing is that the climate in Australia did not change at that time, and the animals were well adapted to it. There is evidence that the migration of people to the region has made a difference. The animals had never seen humans before and did not understand their hunting tactics. In addition, people already knew how to burn the forest, which quickly destroyed the inhabitants of the territories conquered by man. However, questions regarding other territories remain unresolved. Scientists still have to work hard to solve this problem.
Marina Ilyushenko