Saturday, May 05, 2007

Are There More Species Now than Ever Before?

Golden Crowned Manakin

Every year about as many previously "extinct" species are "found" and crossed off the list as are added to the list.

Recent examples include the pale-headed brush-finch, the coontail plant, the Uinta Mountain snail, the Golden-crowned manakin, the Ventura Marsh Milkvetch, the San Fernando Valley Spineflower, the Los Angeles Sunflower, the Bavarian Pine Vole, and Gilbert's Potoroo.

The IUCN notes that "In the last 500 years, human activity has forced 816 species to extinction." yet the IUCN also make regular announcements about formerly "extinct" species being refound.

The question of what to do with animal and plant species that are "created" or "recreated" also muddies the water somewhat.   Selective breeding is bringing back the extinct Burchell's zebra and Quagga, for example, while hybridization is occurring so often between plant and animal species that species creation of some kind is clearly occurring at a very rapid rate.

If we are willing to declare the Asian lion a separate species teetering on the edge of extinction even though "the [genetic and visual] difference is less than that found between different human racial groups," why not count the fertile progeny of lion and tiger crosses as a new species as well (ligers and

Bird and plant crosses are so frequent that they are almost impossible to list and document.

So are we losing species or gaining?  Can it be said -- straight-faced -- that there are now more species than ever before?


1 comment:

TheTruthMatters said...

According to Seth Shostak in the book "Confessions of an Alien Hunter" (2009, page 104), 'More species than ever now reside on Earth.' The statement is not attributed to any source.
Any idea where he might have gotten the information to make such an assertion? I was surprised by it and am looking for confirmation or rebuttal. Thanks.