Question: How many organisms are in the world today?

Clare Woulds answered on 13 Jun 2011:

I don’t know the answer to this, but I do know that it will be an extremely large number. I’m also fairly certain that nobody knows for sure, but some people have probably come up with pretty good estimates. Trillions at least I should think, especially if you’re counting all the micro-organisms, but even that may need to be multiplied by thousands or millions or billions.