About what percent of Earth's living organisms have been "discovered" at this point?

Question

I'm sure I heard a number for this at some point, and I'm curious about not only what that number is, but how scientists have come up with it.

Answer 1

Any numbers like that are made up.

Just recently they found a treasure trove of new species that no one ever dreamed of, so that shows how ridiculous those percentage numbers can be.

Answer 2

The number that you often hear is 10%

http://www.msnbc.msn.com/id/20109284/

However, many of the people I respect say it's probably closer to 1%. Nobody really knows for sure.

Many of them are microbes. One way of getting a feel is by using polymerase chain reaction (PCR) to amplify and sequence even minute amounts of ribosomal RNA gene sequences from soil, water, human gut, etc. The number of new sequences/species that you find gives you some sense of the diversity and what you've missed. Even then you are only finding a few of the species.

You'd be suprised how many are out there--about 500 species in the human gut alone, and that's a pretty limited environment.

Answer 3

How can you get a % when the total isnt known?
They factor in thing's like food, breeding and many other thing's, but end the end is just a guesstimation.