Subscribe to our newsletter. Email Facebook Twitter. Tree adapted from Upham, N. Inferring the mammal tree: Species-level sets of phylogenies for questions in ecology, evolution, and conservation.
PLoS Biol 17, e In this extinction event, many small organisms of the sea became extinct. The next mass extinction is called Devonian extinction, occurring million years ago during the Devonian period. This extinction also saw the end of numerous sea organisms. The largest extinction took place around million years ago. Although life on Earth was nearly wiped out, the Great Dying made room for new organisms, including the first dinosaurs.
About million years ago, between the Triassic and Jurassic periods, came another mass extinction. By eliminating many large animals, this extinction event cleared the way for dinosaurs to flourish. Finally, about This is the famous extinction event that brought the age of the dinosaurs to an end. Those niches allowed for new groups of organisms to thrive and diversify, which produced a range of new species. In the case of the Cretaceous extinction, the demise of the dinosaurs allowed mammals to thrive and grow larger.
Scientists refer to the current time as the Anthropocene period, meaning the period of humanity. They warn that, because of human activities such as pollution, overfishing, and the cutting down of forests, the Earth might be on the verge of—or already in—a sixth mass extinction.
If that is true, what new life would rise up to fill the niche that we currently occupy? The period ended with extinction of the dinosaurs and the rise of mammals. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.
Tyson Brown, National Geographic Society. National Geographic Society. After the reptiles suffered during the end-Triassic event, the surviving dinosaurs took over the planet and diversified. Although a mass extinction ended the dinosaurs, they only evolved in the first place because of mass extinction. Despite this chaos, life slowly diversified over the past m years.
In fact, several things hint that extinction drives this increased diversity. For one, the most rapid periods of diversity increase occur immediately after mass extinctions. In a recovery, animals innovate — finding new ways of making a living. They exploit new habitats, new foods, new means of locomotion. For example, our fish-like forebears first crawled onto land after the end-Devonian extinction.
It also drives evolutionary innovation. Innovation may increase the number of species that can coexist because it allows species to move into new niches, instead of fighting over the old ones. Species can diversify without driving others extinct.
But why does extinction drive innovation? These studies point to the idea that human activity, which is driving this mass extinction, might also be driving rapid evolution. It fuels adaptation. The big cats were on the verge of extinction, so scientists introduced cougars from Texas to breed with the panthers.
Now the panther population is stable and genetically healthy again. But with the threespine sticklebacks there was too much hybridization, since both of the original species are now extinct. The separate roles they played in the lake ecosystem are no longer being filled, which is changing the lake. The three-spine stickleback usually forages and builds its nest near the lake bottom.
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