Author: Juliette Jowit
Link: http://www.theguardian.com/environment/2010/mar/07/extinction-species-evolve
Summary: Humans are driving animals and plants to extinction faster than new species can evolve. Conservation experts have already signaled that the world is on the verge of the "sixth great extinction" of species (the fifth great extinction killed the dinosaurs), due to the destruction of natural habitats, hunting, the spread of alien predators and disease, and climate change. Although it is difficult to measure the rate at which species evolve, scientists can now be sure that extinction rates are faster than that of the evolution of species. The IUCN calculated that the rate of extinction had reached 100-1,000 times that suggested by the fossil records before humans. Swedish scientists have warned that anything over 10 times the background rate of extinction – 10 species per every million per year – was above the limit that could be tolerated if the world was to be safe for humans. Currently, one-in-five mammals, one-in-eight birds, one-in-three amphibians, and one-in-four corals are considered under threat.
Relevance: This connects to the units of evolution and ecosystems. We've learned in the evolution unit that evolution requires mass death, because species that aren't well adapted to an ecosystem usually cannot survive. However, it's not that these animals and plants aren't suited to their environment - their environment is being removed or changed faster than natural selection can provide these new traits. It also connects to our unit on ecosystems in which we learned that effects of introducing alien species. These alien species are being transported by people and then killing off native species by outcompeting them.
If the extinction rate keeps going with no fluctuation, how long do scientist predict it will be till the sixth great extinction?
ReplyDelete"According to Richard Leakey and Roger Lewin, authors of "The Sixth Extinction," we could lose half of all species on Earth by 2100. " http://science.howstuffworks.com/life/evolution/sixth-major-extinction1.htm
DeleteIt's also important to note that other natural disasters could speed up the process. For example, the super volcano at Yellowstone or a meteorite striking the Earth could have colossal effects. Ultimately, scientists aren't too sure because this rate of extinction is occurring extremely quickly, so they have to keep changing their predictions.
Are there any common animal species which are under threat?
ReplyDelete