Astrobiology in the Classroom
NASA – CERES
Project –http://btc.montana.edu/ceres
“Microbial Zoo”
In this activity, students will explore the extreme conditions life is known to exist in on our own planet. They will see that life can exist in a variety of environments, broadening the prospects for life to exist elsewhere in the universe. As humankind begins to look for life among the stars, it is critical to understand the variety of conditions in which microbial life is found, so that it will be easier to identify other worlds where it might exist. These activities involve students in broadening their criteria for life by examining those extreme environments on Earth, then looking at how those lifeforms could exist on other known worlds within our solar system.
Part I –
Exploration:
Living in a Microbial Zoo
- Describe an environment on Earth that would not allow
any form of life to exist.
List specific examples, and explain why these
environments cannot support life.
- Circle
areas on the map of the world below that correspond to places on the Earth
having conditions that prohibit
life.
Australia Antarctica
- Get
together with a partner.
Compare and discuss your responses to the previous questions. Answering questions A and B
below. Then use a different
colored pencil or pen to note any changes you would make in questions 1 or
2.
- Are there any of your
partners’ examples you would like to add to your own, or vice
versa?
- Are
there any that you would like to eliminate from your list?
- After
surveying a large number of college and high school aged students, it was
discovered that the three most common environments listed as being unable
to support life were (1) environments in which there is no oxygen, (2)
environments of extreme temperature (too hot/too cold), and (3)
environments without access to water.
- Did you or your partner include
any of these environments?
- If
you didn’t, do you feel that you should have? Explain why or why not.
- Scientists
are currently searching for life on other planets and moons both inside
and outside our solar system.
What types of life form do you think they are most likely to find
(1) animals, (2) plants or (3) microorganisms? Explain your reasoning.
Part
II – Concept Introduction:
With the growing interest and of
the new multi-disciplinary science of astrobiology, there has been an increase
in funding for research projects investigating life forms living in extreme
environments on Earth. The term
extreme environment is meant to describe any environment that is extreme with
respect to humans. As a result of
this research, we are finding that life exists in virtually every environment
on Earth. However, most of this
life is in the form of microorganisms.
Microbes that thrive in extreme environments are lumped together under
the generic name of extremophiles.
Extremophiles can be further classified according to the environments in
which they live. Examples of
specific extremophiles are thermophiles, psychrophiles, acidophiles,
alkalophiles, barophiles, xerophiles, halophiles, and anaerobes. Your teacher will now show you a Power
point slide show introducing you to these microorganisms. Get a blank chart of extremophiles to
help you take notes during the presentation.
- Now that you have seen the
presentation, refer back to the environments listed in problem 4.
Do you think that any of these
environments actually present conditions too extreme for life to exist?
- Based
on your responses to problem 6, what is the one environmental condition
that all life needs to survive on Earth?
Part
III – Concept Application:
1. You will now receive a data
sheet listing some extreme environments in our solar system. What is it about each of these environments
that makes them extreme?
- Mars
- Venus
- Europa
- Titan
- Io
2. If you were
searching for life on the planets/moons listed on your data sheet, what types
of extremophiles might you find?
Explain your reasoning.
- Mars
- Venus
- Europa
- Titan
- Io
- Which
planet/moon do you feel is most likely or able to support life? Explain your reasoning in detail.