Bacteria Outweigh Animals By HOW MUCH?! Measuring Earth’s Biomass


Greetings home planet and all hail our supreme
Zorgdorg. Mission update: I have completed my biological analysis of
this planet’s life forms. There’s a lot of something called “cows”. As well as “ants”. Glad our home planet doesn’t have those. WOW! So many. I have concluded this planet is actually run
by small birds called “chickens”. They outnumber the humans 2 to 1. HAHAHAHAHA and these humans think they are
in charge HAHAHA actually the humans do kill a lot of
stuff. Wish me luck. More research to come. [Open] What would it look like if we, or aliens posing
as YouTubers, took a census of all Earth’s life, put it on a scale… to see what dominates,
and if we’re changing it? There are a lot of humans on Earth — about
7.6 billion, in fact. But there are actually way more chickens,
19 billion! And way way more fish – those estimates
are in the trillions. We humans actually only make up one one-hundredth
of one percent of all life on Earth, by mass. That hasn’t stopped us from having a big-time
impact though. Sure, we’ve altered the landscape which
is actually visible from space, and we’ve literally moved mountains, but there’s also
an impact that’s a bit harder to see: all the death. Since our species spread across the globe,
we’ve trampled out 84% of animals and over half of all plant life. Sheesh, so what’s left? Counting individual animals is hard and boring
and would take a really long time, so instead scientists often measure something called
biomass, basically how much living mass there is in some group of species. We measure biomass in gigatons of carbon. This is helpful when you want to compare species
of different sizes. For example, 3,100 mice have the same biomass
as one human. Or 15,312 Humpback whales have the same biomass
as your mom.REAL MATURE GUYS Scientists recently found our planet hosts
a total of 550 gigatons of living carbon. So how does it stack up? Let’s start with animals. Of all animals, mammals and birds only make
up 8.5%. And among that, 60% is livestock, mostly cattle
and pigs. Humans? We’re more than a third (36%) of all birds
and mammals, but we’re only 3% of the animal tally. Arthropods — the insects, spiders, crustaceans
and other things with exoskeletons — far outweigh any other animal group, making up
60% of the animal kingdom. I mean, the termites alone nearly outweigh
all 7.6 billion of us humans! But altogether, animals are a tiny 0.3% of
Earth’s living mass. Mushrooms and other fungi are six times more
massive than all the animals. There’s actually a colony of mycelium — an
underground fungus… fungi… fungusi — in Oregon that stretches 1,665 football fields
in area. It’s considered the largest organism on
Earth. However, even fungi and fun-gals are just
a tiny fraction of biomass compared to another group, one that’s absolutely massive despite
being mini. A typical bacterial cell is a tenth the size
of your typical animal cell. Yet together, bacteria are a whopping 35 times
more massive than all animals put together. Bacteria make up most of the small world,
but the other groups of microscopic critters each individually outweigh birds and mammals
(0.3% of total B) on the biomass scale (archaea (1.3%), protists (0.7%), and viruses (0.04%)). But bacteria aren’t the biomass-masters. The true rulers of Earth’s biosphere? Plants. Our green friends make up a whopping ~83%
of all biomass. This result surprised scientists, because
we tend to think of bacteria playing the biggest role in Earth’s biosphere. But when you think about how heavy a tree
is, and the fact that there’s 3 trillion trees on Earth, their top spot makes sense. But then you think about the fact that they
did all that by eating air and… Although most of the Earth’s surface is
covered by ocean, turns out most of life, 86%, lives on land. It might be a blue planet, but it’s a green
biosphere. And even more surprising, there’s almost
12 times more life deep below ground, mostly microbes, than there is in the ocean. So that’s how life on Earth measures up. Thing is, that tally used to look pretty different. Humans and our close relatives have only been
around about 6 million years, but in that short time we’ve managed to decimate life
on this planet. From 50,000 to 3,000 years ago, half of Earth’s
large mammal species died out, due in part to human activity. Whaling alone decreased marine animal biomass
fivefold since the 1700s. Things like deforestation, hunting, and destroying
habitats have knocked down terrestrial animals by a factor of six since we showed up. And don’t even get me started on climate
change. Actually, DO get me started… and go check
out our new climate and environment channel called Hot Mess 🙂 Link in the description. Where were we? Humans have also added new life to the mix
– the planet now hosts more livestock than wild animals. To feed ourselves and our animals, we’ve
permanently cultivated nearly 600,000 square miles. If you add in pastures and stuff, about 18.9
million square miles has been turned over to agriculture — and our livestock are hogging
68% of that. Human population growth is slowing, but it’s
still going up. By 2050 we’ll have something like 9.7 billion
people aboard spaceship Earth, and who knows what that additional human biomass will do
to the planet. If we keep adding more cows and chickens and
people, lions and tigers and bears might only exist in storybooks! Plants, bacteria, and chickens, though, will
probably still be here. Stay curious.

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