The questions posed in Chapter 1. Introduction are discussed further on this page. Remember, some questions are intended to be thought-provoking and more than one answer may be "correct". Users are encouraged to expand upon the discussions here.
1-1. Do you think the scientific method is something only a scientist would use?
The scientific method is something that is taught, so we might question just how natural or intuitive an approach it is. Think about how you discovered answers to interesting or difficult questions as a child. You might have first sought the opinion of an expert (like your dad, right?). That is the first step used by a scientist as well. Scientists learn to seek the expertise of others that have asked similar questions and come up with at least partial answers. This does not require contacting other scientists; more often it is a matter of becoming very familiar with the literature (the written and published record) on the subject of interest. Scientists rarely formulate hypotheses without first learning all they can about a subject from what has been published already. In effect, they learn how to put their question at the very forefront of knowledge about a subject. There are so many questions to be answered in science that no one would want to expend a lot of energy asking and answering questions to mysteries already solved. Of course learning is different. Asking questions and seeking answers from books, journals, and other sources is a valid approach to this first step of learning, and one you and any scientist would have in common.
Formulating a proper question or a hypothesis is perhaps the most difficult step. Recall that the hypothesis is not really a question but an answer. The question is the wonder about something; the hypothesis is a testable answer to that question. It is not THE answer, just a reasonable one posed in such a way that an experiment can be conducted to ascertain its validity. You may see this step expressed as making a guess; but consider that after he or she has completed the step described above—learning everything written about a subject—the scientist is in a position to make a pretty good guess. This step could be difficult for the scientist because he or she must have in mind one or more experiments to conduct to test the hypothesis. This step may be difficult for you for the same reason, and because it probably feels odd to answer a question before investigating it. The hypothesis step is included in the scientific method to promote intellectual honesty and to allow others to better understand a scientist's reasoning when reviewing what was done and how a conclusion was reached. Compare these scenarios:
- Conversation over a radio from technician defusing a bomb –
- OK. I have the device out. There are two black wires and a red one to the timer. Let me try this...<BOOM>!
- OK. I have the device out. There are two black wires and a red one to the timer.
- I think the red one controls the detonation (Hypothesis: An intact red wire is necessary for detonation)
- I am going to cut the red wire (Testing the hypothesis)
- oops <BOOM>
In the absence of any further report from this technician, only the second procedure provides any information to the next technician faced with a second, similar bomb. He at least knows what not to do! Note also that the hypothesis is falsifiable. Testing demonstrated whether an intact red wire was or was not needed for detonation (apparently it controlled the undetonated state). Framing the hypothesis thusly: the red wire serves a purpose cannot be proven false; what test could you devise to satisfactorily demonstrate it has no purpose? It may in fact have no purpose (not in the example above), but eliminating by testing every possible purpose under the sun is an unsatisfactory approach.
1-3. When you catch a cold a virus has infected your body. Why do you think there is reason to question whether the virus is living or not? After all, if you took some ricinin (a plant poison), you would get very sick, but no one would suggest the toxin were alive or that the plant had entered your body.
Ricinin is an alkaloid and, along with the toxalbumin ricin (a plant protein), constitute extremely toxic substances found in the seeds of the castor bean (Ricinus communis) plant. Were you to ingest several raw seeds, you would experience nausea and vomiting, stomachache, bloody diarrhea, headache, cold sweat, sleepiness, disorientation, fever, shortage of breath, seizures, and possibly collapse and death. While there are a number of different ways that a virus could enter your body, the most common would be breathing in virus particles while in the presence of an infected person. The outcome of such exposure could be pretty much the same as that described for ricinin ingestion, depending upon the type of virus and your body's ability to respond appropriately to the "infection". Or, perhaps the infection you "catch" is cholera—the Vibrio cholerae bacterium. These bacteria are typically ingested in drinking water contaminated by improper sanitation. Again, you might display many of the same symptoms described, including the really unpleasant part about dying. The point here is to consider which of these problems constitute an "attack" by another living organism and which represent simply a poisoning of your living body by a non-living chemical. You cannot use the resulting symptoms as an indication because....; well, because they are just symptoms: what you "feel" as your body reacts to the chemical or biological attack.
In the case of ricin, this protein inhibits protein synthesis within the cells of the body. Organ damage results. Vibrio cholerae in the body produce a chemical that results in a loss of fluid and salts across the lining of the gut. The resulting diarrhea allows the bacterium to spread to other people under unsanitary conditions, and can result in death due to dehydration (an inability to retain water). So both the non-living chemical and the living bacterium cause illness by toxicity to our bodily functions.
You should recognize one pretty significant difference between an illness caused by a living organisms and an illness caused by a non-living, but toxic, chemical. In the latter case, the severity of our symptoms will be pretty much dependent upon the dose of toxin we ingest. There will be just so much chemical entering the body, and the damage should be proportional to that amount. In the case of the bacterium, something like a million cells need to be ingested to result in an infection, but once established, the living organism is a tiny factory that cranks out toxin and reproduces more identical factories (more cells) that themselves produce toxin. So the dose of toxin we get from the bacterial infection is not obviously limited. Living cells metabolize (break down and produce chemicals for various purposes) and reproduce (increase their numbers).
In essence, this is what is meant by an infection: another life form has taken up residence in or on our body, and is utilizing organic substances that are a part of our life processes to carry out its life functions, to further its existence and numbers. In the case of chlorea, the bacterium has some nasty habits that make us very ill; but there are a number of other bacteria (Escherichi coli, for example) that live in perfect harmony within or digetive tract and help us digest food. So not every "alien" that invades our body necessarily causes an infection.
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