The Holocene Extinction Event

You may be wondering how many species are now extinct, is it thousands or millions? Think about it. Plants, and animals… dinosaurs, the Dodo bird… Probably there are billions of species that are now extinct. Some evolved, but most have died off, leaving no decedents. In fact it is estimated that off all the species that have ever lived, only 0.1 % are alive now. And these are going extinct at faster rates than the earths history has ever seen.

When most people think of mass extinction they think of the one that gets the most public attention as it wiped out the last of the dinosaurs. But there is a mass extinction event happening now, it is the sixth mass extinction event, and is known as the Holocene Extinction.

 http://en.wikipedia.org/wiki/File:Quagga_photo.jpg 

Above the Quagga, the last one died in captivity in 1883, the last wild one was shot in the 1870’s hunted to death for their fur. 

By studying patterns scientists now find that most species survive for roughly 10 million years then become extinct. As such we know what an normal extinction pattern should be.

The interesting thing is that starting about 10,000 years ago, extinctions among plants and animals are occurring at alarming rates. What happened to trigger this? Most scientists agree that humans, and human activity are to blame. Through our spread we have contributed either directly (as in the Passenger Pigeon), or somewhat more indirectly (as in the Dodo bird), to an increase in extinction rates in other species. This current mass extinction event is called the Holocene Extinction.

http://en.wikipedia.org/wiki/File:Passenger_pigeon_young.jpg

Above the Passenger Pigeon was once one of the most common birds in North America.  Eventually hunted to extinction using some of the must cruel methods, including tying a live birds eyes shut and using it as bait to encourage other birds to land. 

Sometimes the extinction of one species means others soon follow. This happens when species are dependent on other species for their survival, usually as means of food. To this extent scientists warn of human extinction being a very real possibility if honey bees should go extinct, as we depend so heavily on plants they pollinate. In fact scientists estimate we might live only 2-5 years longer without bees. A similar problem may occur if ants were to vanish, as they also fertilize many plants. A worse mass extinction would occur if grasses were to suddenly die off, as many things such as rice, and corn, are grasses, and many of our food animals rely on grasses for food.

As we use more pesticides, and herbicides, and genetic engineering to make life better for us, are we bringing our own eradication from the plant? Will pesticides kill so many bees, and ants, that their numbers will not recover? Will terminator seeds somehow result in a world where grasses no longer reproduce? Will humans success cause their own extinction and bring an end to this event?

 http://en.wikipedia.org/wiki/File:Hydrodamalis_gigas_drawing.png

Above the Stellars Sea Cow, hunted to extinction only 27 years after its discovery by Europeans. 

In the 20th Century, an estimated 20,000 to two million species became extinct. These numbers were based on current discoveries of species, and the knowledge that many new species are being discovered but with habitat destruction (eg. deforestation through slash and burn), certainly many species were eradicated before they were discovered. Most of the documented extinction were of larger animals, such as the Dodo bird, the Quagga, and Passenger Pigeon.

http://en.wikipedia.org/wiki/File:Peredaviddeer.JPG

Above is Pere Davids Deer, one of many animals listed as extinct in the wild, they are only alive in zoos.

The Holocene extinction event is killing species at 100 times the rate of normal extinction patterns. With a long list of species who are at risk or highly endangered, who, or what, is next?

Other Reading

When Will Humans Go Extinct

How Human Activity Made a Sea Vanish

Not All Prehistoric Animals were Dinosuars