Here’s a brief report from New Scientist, discussing research by Markus Pfenninger and Klaus Schwenk, of the Goethe-Universitat in Frankfurt, Germany, who have been engaged in a project which aims to ‘barcode’ every living organism on the planet.
Cryptic species – animals that appear identical but are genetically quite distinct – may be much more widespread than previously thought. The findings could have major implications in areas ranging from biodiversity estimates and wildlife management, to our understanding of infectious diseases and evolution.
Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles, and were more likely to occur in tropical rather than temperate regions (see Trends in Ecology and Evolution, vol 22, p 148).
“Species that are seemingly widespread and abundant could in reality be many different cryptic species that have low populations and are highly endangered,” says Pfenninger. Until the genetic information of all species in at least one taxon is thoroughly studied, no one will know just how many cryptic species exist. “It could be as high as 30%,” Pfenninger says.
Even megafauna that we might consider to be a single species turn out to have surprises of their own – for example, than African elephant has been shown to be two independent species that do not breed with each other – namely the Bush Elephant and the African elephant – moreover, gnetic studies of a butterfly species, the neotropical skipper, turned out to be no less than 10 separate species.
The reclassifications are more than an academic exercise. They define populations that have evolved independently of each other and whose genetic differences can have significant consequences.
In the early 1900s misidentification of mosquito species based on morphology confounded attempts to control malaria in Europe. Ultimately, what was thought to be a single species was actually made up of six sibling species, only three of which transmitted the disease.
“The basic unit in biology is always the species, and you have to know what you are dealing with,” Pfenninger says. Much previous research is now obsolete, he says, because it is not clear what species was being studied.
Pfenninger is now trying to determine whether cryptic differentiation is simply an early stage of morphological differentiation – but preliminary results suggest not.
In it’s own quiet way, this effort to genetically catalogue all life on Earth could turn out to be one of the most effective tools to have come along for some time, particularly when considering issues related to hominid evolution over the past 4 million years and more. (TJ)
see also: New Scientist, Feb 2007, ‘Genetic ‘Barcoding’ Reveals Slew Of New Species‘
image: periwinkle snails