The Sixth Extinction
Habitats are being destroyed around the world, and we don’t know what the consequences are because that’s not the case with other species extinctions. They didn’t remove habitat on a large scale because of a species’ activity. Previous mass extinctions have often been the result of external disasters—meteorite strikes, widespread desertification—but never before have we had a single species big enough to house so many others.
Earth’s climate undergoes continuous change, determining the number and diversity of species in each period. The concept of biodiversity refers specifically to the abundance of life in a given time and space. This is a calculation that measures the diversity of species, taking into account the ability of these species to interbreed. There is little distinction between insects, plants, and mammals, because each is important…not just because it lives, but because life depends on it.
The number of species that exist today is unknown. There are about 2 million classified species, although no one really knows what percentage of the total number of species on Earth that number represents. Scientists are divided on estimates, with some putting at least 4 million species, while others are more optimistic and put the number at more than 100 million. Between these two extremes, the most accepted figure is about 14 million different species.
The dominance and variety of small animals is not a whim of nature… small animals fill a need. Without insects, the machinery of life cannot function. They remove biological debris from ecosystems, oxygenate soils, and provide food for hundreds of species of birds, reptiles, and mammals. Most importantly, they are vital to plants, whose reproduction is almost entirely dependent on the millions of insects that transfer pollen from one flower to another.
