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- What do we humans need
to survive?

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Well, we need food, oxygen,

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water, and living space.

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All those things are normal
for us,

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but did you know
that there are organisms

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living on Earth right now

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that don't need the same
things we need to survive?

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These organisms live in places
like this one.

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That would be terrible for us,
but perfect for them.

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Because they live in such
extreme conditions,

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scientists call them
extremophiles.

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Extreme!

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[music playing]

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Well, not like that.

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Let's refocus.

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But what exactly is
an extremophile?

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- So an extremophile
is an organism

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that can thrive in extreme
environments.

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And what I mean by that,
it's environments that you or I

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would find to be
very inhospitable or hostile

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to what we need
in order for us to thrive.

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So an example is an organism
that would live

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in extremely warm or extremely
cold temperatures.

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And that could be an organism
in Antarctica,

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it could be organisms that
are thriving in the middle

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of a desert that's extremely
hot with lots of sunlight.

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There are many
extreme environments

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that would be damaging to us,
as humans,

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but there are microorganisms
that just love living there.

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So we study extremophiles
because they tell us

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the limits
to life here on Earth.

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And it turns out that almost

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every possible environment
on Earth

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has an organism living in it.

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So one of the most interesting
extreme environments

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that I've learned about
is environments

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that have very low pH.

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So we typically live
in an environment

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where the pH is somewhere
around seven.

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That's called neutral pH.

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Some organisms can live in pHs
all the way to zero,

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really acidic.

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And just for perspective,

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battery acid that comes out of
the batteries in your car

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are pH of one.

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Soda is actually pH
of about two.

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If we were to try to live
in a can of soda,

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our bodies would start
to dissolve

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because low pH, or acid,
will break apart our skin.

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But an organism--
a microorganism can actually

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live at that pH.

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It can get nutrition
from the soda,

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as well as survive that very
low pH environment.

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- Who knew these microscopic

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and often very creepy-looking
organisms

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could give us
so much information

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and mean so much to NASA?

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Curious as to where we can find
these extremophiles?

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Tune in for part two
on our world.

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[music playing]