Name________________________________
Science 7/Period_________________
Date ________________
Garrido
LIFE IN EXTREME ENVIRONMENTS
Go to: http://learn.genetics.utah.edu/content/astrobiology/conditions/
What makes a planet habitable?
Even if we assume any _________________ must be __________ (and it may not be), chances are we're not
_______. Astrobiologists estimate that the ______________ has ________habitable planets, which fit the
following criteria:

They're a __________________________ from a star similar to __________. That is, they're far
enough away to be out of the _______________ and _______________, but _____________ that
they're __________________. This just-right distance is called the "___________________."

They're made of __________. __________, __________, and ____________ in our solar system are
made of __________, so we ________ expect life to be able to _________ there.

They're ________________to have a ____________. Earth's core gives us a source of
____________________, it allows _________________________, and it sets up a ______________
around the planet that ____________ us from _______________. _______ probably had a hot liquid
________ at one time, but because it's a __________ planet its _______________ more __________.

They are good candidates for having a _________________________. The ______________ holds
_________________ and ______________ that keep the planet _________ and _________ its
surface from _____________.
What about intelligent life?
Even today, most Earth life is _________. And microbes have been here for at least ____________ years—a
very long time when you consider that the ___________ formed about _____________ years ago. Given the
number of potentially ________________________ within our ___________________, chances are _______
that __________________________________________ elsewhere.
Whether ______________ life forms like _________ and _________ exist elsewhere is a ____________. For
______________ years or so, all life on __________ was _____________. Multicellular, _________________
and ___________ came onto the scene about ______________ years ago. That's about _____ of the total time
that life has ________ on __________.
It's _____________ to say how likely we are to find other ___________________. The _________ fossils of
our ________, ___________________, are less than _________________ years old. That's a
____________________________, just ___________% of the time _________ have been around. If, like on
_______, _______________ life takes much ________ to evolve than __________ life, it might be _______.
But some _________ and ____________________ are much _________ than _______, so maybe other
_____________ life has formed; however, it may be ___________. Finding _______ intelligent beings is a
matter of both __________ and _____________.
Looking for signs of life past or present
Just as __________on __________ have changed drastically ____________, so have conditions on
___________. When ___________________ evaluate a ____________, they look not just at its
________________, but for ________ that it could have been _______________ in the ____________.
__________ water leaves behind a kind of __________. ________, for example, has what looks like _________
and ________________, making ________________ wonder if the _________, _______ planet could have
once been covered with _______. If it was, there may be enough remaining _____________ water to sustain
_____________ life ____________________________or ______________________________________.
_________ things ________ their ______________, leaving behind certain ___________ and
___________signatures. Even a planet that is ________ today could have ______________ of ancient
__________. ____________ and ____________ remnants can tell us a lot about what _________ might have
_________________.
Go to: http://learn.genetics.utah.edu/content/astrobiology/environments/
Life can be found in the most ____________. In some of earth’s most ________________, survivors called
___________________ tolerate conditions that would kill _______________.
_______________ teach us about the _________ of life. They give us _________ that ________ could
exist on _________________ and ____________ in this _______________ and _______________.
Earth:
1. Tardigrades
Location: ________________
Your own backyard may be a habitat for one of the planet’s most extreme creatures, called ____________.
Tardigrades or “______________” have been found almost everywhere, including the __________,
___________, and _________________. These tiny creatures, not much longer than a millimeter, are
almost indestructible. They can survive being ___________, ___________, ______________,
___________, or ___________________. Recently they even survived ____________.
2. Yellowstone National Park
Location: Wyoming, USA
Volcanic hot springs dot the land in Yellowstone National Park, Wyoming. The ____________ pools vary
widely in ____________, ___________, and _______________. Diverse communities of
_____________thrive in these extreme conditions. Resident microbes eat __________ dissolved in the
water, including _______________, ______________, and _____________. Archea (not bacteria) are the
________________ for living in near-_________________.
3. Great Salt Lake
Location: Utah, USA
Utah’s ________________ is much ____________ than the ___________. Fish __________ survive
there. But whole communities of salt-loving ________________, including ___________, _____________,
and _____________. These microbes in turn support ________________ and ________________. Brine
shrimp and brine flies are an essential ___________ for millions of ____________________.
4. Cueva de Villa Luz
Location: Tabasco, Mexico
Cueva de Villa Luz is a _____________, __________ place literally dripping with _____________.
Hydrogen ___________ rising from murky springs in the cave floor gives the air a _________________.
Here cave microbes get ___________ by combining _______________ with _____________ from the air,
releasing ________________ as a byproduct. The microbes form slimy “_____________” – little
_______________ that hang from the _________________. Tiny,
acid-resistant ______________
eat the ______________, and ______________ eat the ______________.
5. Pitch Lake
Location: Trinidad
Pitch Lake is a hot _______________, bubbling with ___________ gases. Located on an island in the
___________, it is the ___________ asphalt lake in the _____________. The asphalt, a form of
______________, is used in ___________ construction. But the _______________ liquid also supports a
____________ community of ___________, including __________, _____________, and __________.
Additional ______________ to life here include the absence of ______________ and
__________________.
6. East Pacific Rise
Location: Underwater Volcanic Mountain Range
_____________ water above __________temperatures spews from _________in the ocean floor.
___________ in the vent water _______a diverse community of __________, which in turn provide
_______ for ________________, including ____________, ___________, ________, and _________.
Bottom-dwelling organisms thrive here despite the ________, __________, and ____________________.
7. Atacama Desert
Location: Chile
The __________________ in northern Chile is the _________place in the __________. Some places have
not seen rainfall in ___________. Scientists couldn’t find ________ in this _____________ until they
looked _____________________. Here, ____________live in ___________________ surrounded by an
ultra thin layer of __________. They feed on _______________ in the ________, including
_____________ (CaSO4) and ___________________ (HClO4).
8. Laguna Verde
Location: Bolivia
High in the _________________ is a group of __________ that lie ______________ above sea level.
Trees _________ grow at this ___________. Yet these lakes are teeming with _______________. Toxins,
especially _____________, are a _______________to life here, as is ___________ to
__________________. Lake microbes have ______________________ that allow them to survive high
doses of ______________, including enhanced ____________________.
9. Sea Ice
Location: Antarctica
As temperatures in ___________drop over ____________, many small ocean organisms _______. But
______________ microbes living sea ice ________. They ________ the remains of _______________
trapped in the ice. Other organisms called ____________ are also specially ____________to
_________________. They make their own food using ________________. The _____________ they use
for _____________________ color the ___________________.
10. McMurdo Dry Valleys (Blood Falls)
Location: Antarctica
At _____________in Antarctica, ____________________ leaks from a glacier. The source of the water is
an _________________ buried beneath ______________of ice. This ocean has been ____________ for
over a _______________. _________ in the __________ reacts with __________ in the air, turning the
water _______________. The high ____________________, ________________, and
_____________________would ________ most organisms, but the _____________here supports a
community of _____________ that use dissolved ____________ and _________ compounds as ________.
SPACE:
11. Europa Moon of Jupiter
_________ rocky moon ________ is encased in a __________________________. Europa __________
have an ________________ and so experiences intense ___________________. But life ________ exist
in an ___________________________ – especially near ______________________, which serve as a
major source of __________________________________.
12. Mars
_______ is a cold (______°C/______°F), dry planet with a ___________________ composed mostly of
__________________. Its ____________________ gives the surface a _______________. If life
exists on Mars, it will likely be found ________________ where ___________from the
_________________ could allow water to exist as _____________. Recent missions to Mars have focused
on ______________ certain _______________in the _________, __________, and ____________ that
would indicate the _____________of life ____________________________.
13. Titan Moon of Saturn
__________ moon __________ has a temperature of ______°F (____°C). But amid this frigid landscape of
_______ and _________ are lakes of ________________, literal reservoirs of __________. Clouds drop
____________________. Icy _____________ spew _________________ and _________________
from Titan’s ______________ to the ______________. The presence of __________________ and
__________________ make Titan the ________ place to search for ______________________.