Scientists have some fairly educated guesses about human populations. Earth has nearly 7 billion people, we're told, and more than 300 million people live in the United States.
But we are staggered by the recently reported estimate that there are almost 9 million species on Earth -- and that we have identified fewer than 2 million of them so far.
"We are really fairly ignorant of the complexity and colorfulness of this amazing planet," Boris Worm, the Canadian co-author of the study that came up with those incredible figures, told The Associated Press.
Animals made up -- pardon the expression -- the lion's share of the species, totaling about 7.8 million. Fungi species followed, with more than 600,000, and there are an estimated 300,000 plant species.
The researchers acknowledged that their estimate could be off by quite a bit. They said the true number of species could be anywhere between 7.5 million and 10.1 million. Other scientists say even that wide range could be significantly off.
But what apparently no one contests is the fact that Earth is home to a stunning diversity of life -- which makes existence for us humans infinitely more interesting.