How many species?

http://www.nytimes.com/2011/08/30/science/30species.html?ref=biologyandbiochemistry
So many left to discover

 

Each year, researchers report more than 15,000 new species, and their workload shows no sign of letting up.Scientists have named and cataloged 1.3 million species. How many more species there are left to discover is a question that has hovered like a cloud over the heads of taxonomists for two centuries and continues to. They’ve already found more than a million insect species, and their discovery rate shows no signs of slowing down.

 

Dr. Worm, Dr. Mora and their colleagues presented the latest estimate of how many species there are, based on a new method they have developed. They estimate there are 8.7 million species on the planet, plus or minus 1.3 million. Other estimates have ranged from as few as 3 million to as many as 100 million. Dr. Mora and his colleagues believed that all of these estimates were flawed in one way or another. Most seriously, there was no way to validate the methods used, to be sure they were reliable.

This is a picture of the world and some of the main species you would find on each continent. Panda in Asia, Wolf in North America, etc.

 

 

 

For the new estimate, the scientists came up with a method of their own, based on how taxonomists classify species. Each species belongs to a larger group called a genus, which belongs to a larger group called a family, and so on. We humans, for example, belong to the class of mammals, along with about 5,500 other species. Confident in their method, the scientists then used it on all major groups of species, coming up with estimates of 7.7 million species of animals, for example, and 298,000 species of plants. Although the land makes up 29 percent of the Earth’s surface, the scientists concluded that it is home to 86 percent of the world’s species.

 

But Terry Erwin, an entomologist at the Smithsonian Institution, think there’s a big flaw in the study. There’s no reason to assume that the diversity in little-studied groups will follow the rules of well-studied ones. “They’re measuring human activity, not biodiversity,” he said.

 

My opinion is that we cannot calculate something of this magnitude simply because it may vary so intensely that our estimates may be off by millions and millions. The only way we may ever find the true total? Well we are gunna be researching for quite some time!