Case Study Bio

links //// http://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science/
http://www.space.com/17963-mars-curiosity.html
http://www.space.com/28019-mars-methane-disovery-curiosity-rover.html

Instructions

1) Follow the National Geographic link about the Mars Viking mission results (Part I), read the article and answer questions from Part I

2) Follow the Space.com articles about the Curiosity mission experiments (Part II and III), read the articles and answer questions for Part II and Part III

3) Write ONLY your answers in the same word document as Case Study 1

Case Study

Part I Questions

1) If you were a NASA scientist designing the studies for finding life on Mars, what would you look for that signified life on the Red Planet? How do you differentiate between life and non-life?

2) What are all the possible characteristics that, would confirm that a material or planet or any object for that matter, contains a living organism?

3) Design an experiment that would allow you to determine whether one of the signs of life you identified above is present on Mars. Describe your hypothesis, control, experimental conditions, variables and the expected results if life is present or absent.

4) TheNatGeo article talked about the Curiosity mission, this article was published in 2012, and the Curiosity mission is already on Mars right now. When the Curiosity scientists were designing the experiments to study life on Mars. The NASA scientists categorized their experiments into three categories:

a. experiments that make no (or extremely minimal) assumptions about the chemistry and physiology of Martian organisms;

b. experiments that assume that life on Earth and on Mars evolved along similar lines and produced organisms with similar biochemical properties; and

c. experiments that assume that Martian life is based on organic compounds (i.e., life is carbon-based) but whose biochemistry differs significantly from that of Earth life (for example, Martian life is not assumed to eat sugars and exhale carbon dioxide). This is an intermediate position between the ones outlined above.

Which of these categories do your above designed experiments fall under?

5) What are the pros and cons of NASA's decision to interpret a positive signal on any one of the experiments as evidence enough to prove that they have detected life on Mars?

Part IIand Part III Questions

1) In terms of finding life on Mars, how is the Curiosity mission different from Viking?

2) Why do you think the scientists chose Methane as a marker for life on Mars? What other molecules would you look for if you were designing these experiments? Think about all you have learnt about molecules involved in making life and required by life to survive, energy being the most important.

3) After reading Part III, it seems like the scientists make a lot of assumptions without having solid evidence. To prove something thing in science, you have to test it many different ways to draw a final conclusion. List some pitfalls in the design of experiments done in Part III. Make suggestions of changes or additions you would make to these experiments.

4) Life on earth survives because of the presence of water. Wherever water is, life is. However, the conditions on Mars are very different from Earth. Do you think it is necessarily true that water would play such an important role in development and survival of life on Mars as well? From the properties of water you know, what do you think could be a replacement for water?

5) Carbon is the backbone of all biological molecules and life. Using your knowledge of the elemental properties of carbon, what do you think could be an alternative element for becoming the most important element in living things? Describe some of the properties of these elements.