View Single Post
Old 03-10-2006, 11:02 PM   #140
Samuel Dravis
@Samuel Dravis
Samuel Dravis's Avatar
Status: Moderator
Join Date: May 2002
Posts: 4,980
Originally Posted by jmac7142
Perhaps this? Maybe something from MIT's biology department? The one from MIT only has three though, two of which (the ones Insane Sith and I have mentioned) fetuses do not have, and the other was not disputed here.
In the interests of being as correct as possible, I asked a biologist I know. She has a B.S. in biology and is certaintly competent enough to answer the question. I showed her the 'requirements' for life, like so:

1. Organization - Living things are comprised of one or more cells, which are the basic units of life.
2. Metabolism - Metabolism produces energy by converting nonliving material into cellular components (synthesis) and decomposing organic matter (catalysis). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
3. Growth - Growth results from a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
4. Adaptation - Adaptation is the accommodation of a living organism to its environment. It is fundamental to the process of evolution and is determined by the individual's heredity.
5. Response to stimuli - A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. Plants also respond to stimuli, but usually in ways very different from animals. A response is often expressed by motion: the leaves of a plant turning toward the sun or an animal chasing its prey.
6. Reproduction - The division of one cell to form two new cells is reproduction. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.
I then asked her "Do these rules describe all life?" to which she answered, "No, it looks like it describes most things, but there's always exceptions." She gave basically the same reasons I gave, and which the wiki article gave (note I did not show her anything save the five rules; I'm not interested in bias).

So there you have it, from the mouth of a biologist herself.

About your sources, however - the first is simply a list of definitions. Pick one and then I'll talk about it. Your second, the MIT one, is an incomplete definition (it clearly says, "For a more extensive definition read chapter 1 of Purves or discuss these properties with your tutor"), so how do you know they aren't describing it more accurately in the textbook?

I notice that neither one of your sources show that a majority of biologists accept that these rules must be strictly followed when defining life, and, when I asked the one biologist I know, she says you're wrong. If you can come up with some type of poll or whatever showing that the majority do believe as you do, then good. At present, though, I'd say you're not convincing me very well.

Last edited by Samuel Dravis; 03-10-2006 at 11:14 PM.
Samuel Dravis is offline   you may: