- [Narrator] Life is everywhere.
It's hard to find a place on the planet
where there isn't life.
Sometimes you might have
to look really close, but you'll find it.
One place where you find life
where you might not expected
is underneath a couple miles of ice.
If you go down to the Antarctic,
which is one of my favorite places,
the ice sheets are very thick,
and basically composed of snow that keeps falling,
compacting and compacting
and compacting until all the air is squeezed out of it.
You get these enormous sheets of ice
because the snow never melts.
Underneath that, the pressure is so great
that the water that's trapped underneath these ice
sheets never becomes completely solid,
and you'll have this lens,
a layer of water known as Lake Vostok
that forms below the ice sheet.
Recently, a group of Russian geologists built
themselves a drilling rig,
and they drilled down through the ice
to sample the water way down in Lake Vostok,
and guess what they found?
Evidence of what might be a sub-ice ecosystem with lots
of species of bacteria
and maybe even more complex life forms
that they don't think came down with the drilling equipment.
And if this isn't extreme enough or you,
we can go to the other extreme,
to places where it's really, really hot.
A famous example of that would be in these amazing bubbling
boiling cauldrons of water
that are welling up from volcanic action
in the middle of Yellowstone Park.
You can do these fantastic tours
and you see these amazing colors in all these pools
and these colors, for the most part,
are being produced in part by minerals
but they're also being produced by life,
single-celled microbes such as bacteria,
huge colonies of them.
We're talking about organisms
that can withstand upwards of 80 degree Celsius,
which would translate to somewhere in the neighborhood
of 180 degrees Fahrenheit.
So we're getting really close to boiling,
and that actually prompts the question from some scientist,
what is the upper temperature tolerance level of life?
One issue that I think we need
to look at here when we talk about life being everywhere
is that we're also talking about something called biomass.
We're talking about the different types of organisms
that live in places, and the numbers
of those organisms combine to give us the weight or mass
of those organisms in a given place.
When I say life is everywhere,
it's everywhere, but it's also really abundant.
Earth in some ways is a kind of living planet.
People have said this before,
but it's really true when you think about it
in terms of the biomass being distributed
everywhere across the earth.
An important second point
is that life is not evenly distributed.
There are ranges, habitats
and distributions that are characteristic
for each species on earth.
These are characteristics of any organism
that can be studied.
The ranges can be big,
or the ranges can be small,
but every species, every type of organism,
has a specific place or places on earth that it calls home.
One of my favorite examples
of how we need to be careful about what we say
or imply about the ranges or distributions
of organisms is those cola commercials you see
where polar bears are comforting with penguins.
The only place where that can happen is in a zoo,
and I'm pretty sure the zookeepers wouldn't be
very happy about it.
In nature, of course, polar bears occur
in northern latitudes.
They occur towards the North Pole.
Penguins, on the other hand,
occur only in the Southern Hemisphere,
towards the South Pole.
Mostly in the southern regions of the earth.
So in nature, of course,
they never mix, because they have different ranges.
The study of the species distribution phenomenon
is something we call biogeography.
Graphy just means writing it down,
getting it figured out, measuring it.
Geo, of course, means earth.
Bio, put the prefix, bio,
in front of all of that,
and what we're actually studying is
where life occurs on the earth
and we're describing what those patterns look
like and how they come to be.
This brings us back to the concept of species richness
that we mentioned before.
How many different types
of species live in a particular place?
We wanna measure species richness in order
to understand some of these biogeography patterns.
We have different ways of measuring species richness.
We go out and do surveys and things
like that and we find that in some areas,
we have greater species richness
and other areas have many fewer species.
There will also be variation in how many individuals
there are making up each species
of what those population sizes are.
So if you take a drive anywhere,
just hop in a car and drive anywhere,
you can see this uneven distribution in the types
of organisms and in the number of organisms as you drive by.
Let's start our rather longish drive in the Arctic tundra.
Even though it's kind of a desert there,
you have a complete ecosystem.
There are different types of organisms
that contribute to that ecosystem,
but the number of species
that live in that tundra is kind of low.
The population sizes may be very high for some
of those species, but the number
of species is actually relatively low.
Except for the tiny microscopic-sized organisms,
you could actually see most of the species
that occur in the tundra from the window of your car.
Let's head south and say drive down the Isthmus of Panama
and enter the Amazon region.
You could look out the window of your car
and you'd see diversity
that's almost too huge to comprehend as you drive by.
The types and numbers
and ranges and distributions
of organisms are almost uncountable,
and we're working on trying to count them,
but it's a big deal.
It's a huge challenge for science.
In the Amazon, we're talking
about an enormous species richness.
Same thing if you go snorkeling say right
here off California,
it's a fantastic place to go snorkeling.
There are wonderful organisms, lots and lots of them.
But now, think about, besides being much more comfortable
in the warmer water, if you go snorkeling
in the Philippines instead.
The diversity and the species richness
and even the actual biomass of the organisms
that you see in a coral reef in the Philippines
is much higher than you'd see along
any rocky shore in California.
And that makes a really great demonstration
that not only do you see these differences
in patterns on land, but you see it in the ocean as well.
On earth, life is everywhere.
It's just more abundant in some places than in others.