Have you ever wondered how successful human beings are as a species? 7,091,689,393. That's
how many human beings there are on Earth, right now (give or take). By most measures,
humans are an amazingly successful species, so how do we compare to the rest of Earth?
At just over 7 billion, humans are near the top of the tally for mammals. But we're
soundly outnumbered by the world's 10 billion bats, which as a group, make up a staggering
1 in 5 mammal species on Earth. Humans are also beaten in the bird world. The African
red-billed quelea is the most abundant bird on Earth, with as many as 10 billion individuals
dotting the savannah and annoying the elephants.
What about in the oceans that cover over 70% of Earth? The score for most fish is hard
to know, but we know that one school of Atlantic herring can be as big as one cubic mile, and
contain more than 4 billion individual fish. Now, when we get to insects the numbers start
to get a little hard to imagine. For instance, if we counted all the aphids, on all the soybean
plants, just on North American farms, we would find as many as a quadrillion aphids. And
social insects take it to another level. Although a single ant is only a few millimeters long,
if we put all of Earth's ants on a scale, they'd outweigh all of Earth's mammals
combined. Ants as a group are thought to make up over 15% of all land animal biomass.
So what's this "biomass" thing? If we could somehow take all the living things in
one place, like a scoop of soil or an entire ocean, and put them on scale, that would be
biomass. It's what populations of living things weigh. So what do we see if we start
weighing different species?
All 7 billion human beings on Earth weigh in at a hefty 287 million tons, but just one
species of krill, which is that tiny crustacean eaten by large whales, weighs a total of 500
million tons on the scale together. Take Aspens . . . now Aspen forests aren't actually
individual trees, they are colonies that grow out from a single clone connected underground.
The heaviest single organism on Earth is an 80,000 year old grove in Utah called Pando,
which weighs in at over 6600 tons. Now speaking of big underground organisms, what about fungi?
There's an underground web of forest fungus in Oregon that covers the area of over 1,600
football fields. It's the largest known single organism by area, weighing more than
75 space shuttles. But if you looked in the soil, the fungal web would be invisible.
In fact, the single most massive chunk of Earth's biomass can't even be seen with
the naked eye. It's bacteria. In a single spoonful of soil, there could be 10,000 species
of the little guys. Take this number: three septillion. That's 24 zeroes. That's just
the number of bacteria in all of the cow stomachs on Earth. If you ask me though, the most amazing
piece of Earth's biomass is something that most people say isn't actually alive: viruses.
They're tiny, they're everywhere, and they infect every branch of life. So how many
viruses are there on Earth? Frankly we don't know, but we do have some good guesses for
the number of viruses in the ocean.
Get this: there's 75 million blue whales worth of viruses in the sea, weight-wise.
If you took all those tiny viruses and stretched them end to end, they'd extend a hundred
times the diameter of the Milky Way galaxy.
So humans have done pretty well as a species, considering that we've only been around
in our current form for about 200,000 years, and just 500 years ago there were less than
half a billion of us. But now there's over 7 billion people on Earth, and by the time
you finish watching this video, there will be several hundred more than when you started.
That means when it comes to getting things like food, energy, and a place to live, we've
got to start paying attention to all the other hundreds of billions of tons of life on Earth.