M4A1 Midterm Essay
1. You are the biologist in a group of scientists who have traveled to a distant star system and landed on a planet. You see an astounding array of shapes and forms. You have three days to take samples of living things before returning to earth. How do you decide what is alive?
If three days is all I have to take samples of living things, then it would be very hard to determine what is truly alive, as the time restriction only allows for certain properties of life to be evaluated. All living things grow, eat, excrete, reproduce, respire, and respond to stimuli. Upon careful observation, I would pick out the “low hanging fruit” or the shapes and forms that exhibit obvious and directly observable properties of life and bring them back for detailed analysis. Things that move, grow, or change colors; things that have observable changes mimicking life would immediately warrant investigation. For things that are not immediately observed, it would have to come down to the physical samples observed under microscope. I would take a small physical sample of everything within reach, regardless of what it looks like or what form it takes. According to Johnson (2013) “All living things are composed of one or more cells” (p. 17). I would observe and record the organization of the cellular structure, learn if and how this cell metabolizes energy, where it captures energy from and what purpose, if at all. If it uses energy, it must surely have waste, which I would look for as well. I would look for signs of growth and reproduction in the cell. I would look for how this cell or organism would execute homeostasis, as well as look for DNA. These are all properties that all living things share.
2. What happens if an atom of an element gains or loses electrons? What happens if an atom of an element gains or loses neutrons? What happens if an atom of an element gains or loses protons?
Atoms in which the...
References: Johnson, G. (2013). Essentials of The Living World (4 ed.). New York, NY: McGraw Hill Companies
Author unknown, accessed 2014 Scienceline University of California at Santa Barbara, can be viewed at http://scienceline.ucsb.edu/getkey.php?key=153
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