“Extinction is for ever” used to be a green movement slogan. It is no longer completely true. Thanks to the wonders of genetic engineering, it is becoming possible to recreate lost creatures provided we have their DNA. The quagga, a species of zebra whose last member died in Amsterdam Zoo in 1883, is one animal that might get the recreation treatment soon.
In case you are wondering, it is far trickier to do this with long-extinct animals with no living relatives, for example dinosaurs. One reason is that the plants they used to eat have also gone extinct and those that exist today might be toxic to them. More importantly, you need a near relative to give birth to the revived species.
Although some creatures can be driven to extinction by humans killing them off, far more are put in danger by having their habitat removed around them. So like climate change, extinction is important in its own right but also for what it tells us about how we are changing the Earth.
The international Union for Conservation of Nature and Natural Resources runs the Red List of endangered species (www.redlist.org). It turns out that the bigger and more noticeable a species is, the likelier biologists are to know about it in detail.
Thus there are 5.416 known species of mammal of which we have detailed knowledge of 4,853. Of these, according to IUCN, 1,101 were threatened with extinction in 2004. For birds the figure is at 1,213 out of 9,917 species which have had been described; for amphibians it is an even more alarming 31 percent, 1,770 out of 5,743 described species.
The IUCN’s tables show that the numbers of species apparently at risk have been increasing consistently since the mid-1990s. Perhaps most alarming is the fact that the list contains over 8,000 species of plants. While people might hunt bears or wolves to death, the extinction of a plant usually stems from gross alteration of the environment, and in turn threatens the animals that eat it.
The IUCN’s headline figures suggest that only about 1 per cent of species are threatened with extinction. However, a far higher percentage of the species that have been studied in detail are in trouble. The figures support an estimate that extinction is now running at anything up to 100 times its normal rate.
Endangered Species and Extinction – Causes and Trends > Mass Extinction Underway, Biodiversity Crisis
