In recent decades, human intelligence has achieved unprecedented species expansion. They have used terrifyingly efficient intelligence to transform other organisms into food that sustains more human beings, and transformed them into products to make our lives more comfortable. The ancestors of this species once experienced a critical moment when there were only a few thousand individuals left, but now they account for 36% of the total number of living mammals. The other 60% are animals like cows, which are raised to feed humans. Only 4% are wild animals.
Despite humans' huge impact on terrestrial ecosystems, we only account for 0.01% of Earth's biomass. However, human beings continue to advance, reducing the living space for other animals and becoming more and more lonely. The sixth mass extinction is the first mass extinction caused by a single animal; previous mass extinctions were caused by meteorites (such as the meteor that wiped out the dinosaurs) and extreme geological processes. And this impact isn't limited to isolated species. An article published in the Proceedings of the National Academy of Sciences (PNAS) points out that entire branches of the evolutionary tree are being destroyed. Animals such as the thylacine and the finless porpoise are the last species in their genus, a category that groups together several related species.
Led by Gerardo Ceballos, a researcher at the National Autonomous University of Mexico, the study used databases such as the International Union for Conservation of Nature database to examine 34,600 species in 5,400 vertebrate genera over the past 500 years. During these five centuries, species in 73 genera became extinct, at a rate 35 times greater than the previous 65 million years. Without human influence, it would have taken 18,000 years for so many genera to disappear. The authors say that at least one-third of all known vertebrate species are declining and being squeezed into smaller and smaller ecosystems. For example, at the beginning of the 20th century, there were 10 million elephants in the world. Today, there are fewer than 500,000 elephants, and until recently, elephants had disappeared from many of the countries they once inhabited.
The loss of entire species affects the functioning of entire ecosystems. The homogenization of their environments imposed by humans has also led to the disappearance of the balance that is conducive to our survival and changed the course of evolution. "In the eastern United States, large carnivores—bears, cougars, wolves—have disappeared and white-tailed deer and mice have greatly increased in their populations. Deer and mice are hosts for ticks that transmit Lyme disease, a very serious disease," Ceballos explained. "This results in millions of cases in the United States each year."
Paul Ehrlich, a professor at Stanford University and one of the authors of the study, said: "We are losing the only biological companion we know in the entire universe."
In addition to exacerbating the spread of diseases like COVID-19 between animals and humans, biodiversity loss and overexploitation of wild spaces contribute to the destruction of resources that could be used to improve human health. Rheobatrachus is one of the extinct frog genera. These animals, native to the tropical forests of Queensland, Australia, have a peculiar reproductive system. The female frog swallows the fertilized eggs, turning her stomach into a uterus where the tadpoles grow. Because frogs must shut down acid secretion in their stomachs to protect their young, they are an interesting model for studying diseases such as gastric reflux and related cancers, but there are no such animals left on Earth today. Although the animals' numbers are small, they may also play an important role in maintaining ecological balance.
Ceballos said the data is a call to action. "If we don't take the necessary action, civilization will collapse. Humanity will not become extinct, but there will be an apocalyptic scenario [like] in the movies where only the strongest survive. In the past, after every mass extinction (sometimes more than 70% of all life on Earth was wiped out), the tree of life would be rebuilt as new species slowly emerged. But this would require 15 million to 20 million Years later, humans can't wait that long. To avoid or mitigate collapse, the authors call for unprecedented investment, with a special focus on protecting tropical forests, where biodiversity is greatest. "Maybe it will cost $400 billion, which is a lot of money, but if we continue as we are now, the scope of the collapse will be much greater than what we are seeing." "
While similar research published in the Proceedings of the National Academy of Sciences (PNAS) sheds some light on the extent of the ecological problems facing humanity, the only known intelligent species in the universe is getting closer to being strangled by its own efficiency in survival and reproduction.