Modularity, A distinguishing property of life

Science has actually eroded the once perceived differences between "life" and "non-life". At the atomic and molecular level there really is no difference between the two. How do you define an organism? Are virus' organic life? Are they an organism? They can replicate, some have large, complex genomes and internal organelle-like structures which can encode proteins (like the mimvirus) and even are larger than the size of the smallest bacteria (mimvirus=400-800 nm vs. mycoplasma bacteria=200-300 nm) and have nearly twice as much genetic material. Also, how do you define cells? Bacteria and archaea have very different cellular structure than that of eukaryotic organisms.Also, here is an interesting scientific article which destroys your straw man argument that intact cells constitute life: Life without a cell membrane: regeneration of protoplasts from disintegrated cells of the marine green alga Bryopsis plumosa That is a very simplified definition of life taught at the 4th and 5th grade science level. It much less black and white once you start studying biology at the molecular level. At that level there really is no difference between the two. Even in high school I learned that the definition of life is not as clear as you make it out to be.This is a difference in semantics, nothing more. Molecular replication and reproduction are essentially synonymous terms. Though the term "reproduction" is often used in biology to indicate replication at a higher level i.e. "cellular reproduction", sexual or asexual; which itself incorporates molecular replication, i.e. DNA/RNA replication, at the molecular level. ROTFL how ironic! You are actually quoting from an article by Thomas Henry Huxley, Charles Darwin's "Bulldog" in the 1902 version of Encyclopedia Britannica? You may want to catch up 107 years to the present state of biological sciences. Besides, nowhere in your source does it say that "life" has to consist of cells only that the general scientific consensus is that "life" has certain properties such as its ability to integrate new matter in more complex forms? Also nowhere does it specific anything that prevents abiogenesis from occurring? Again "life" is an arbritary term that is currently in a scientific battle of semantics. There is no dividing line between living organisms and the organic and inorganic molecules they are composed of. Or are you advocating for some type of "spark of life" that distinguishes between the two? Where Huxley say that life has to consist of cells? He says that living organisms are composed of certain molecular compounds not generally found in non-living things (however this is no longer true as amino acids and other prebiotic organic molecules have been found in remote regions of interstellar space: http://www.spaceref.com/news/viewpr.html?pid=18569 ). Huxley did not have modern day molecular biology at his disposal to refine his definition of life. If he did I am sure he would have revised much of what he written here. Again Huxley was unaware of life-like entities called viruses and prions which are capable or replicating/reproducing. Here is an interesting article which explores the vacuous meaning of the term "life" and how ambiguous it really is. Defining Life
I beg to difer as explained above with viruses, prions and the like.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Sorry about the delay in replying, I had a pretty hefty project at work that took up my time.-------------------------------------------------------------------------------- Let me qualify that at the molecular and atomic the answer is no, we cannot tell the difference between carbon atoms or hydrocarbon molecules in a rock and those in a human body. It is only as we zoom out and see the collection of atoms on a more macroscopic level (i.e. micrometers and higher) that we can differentiate how these vast collections of atoms interact with each other that differentiate biochemically evolving systems aka "life" from non-biological systems aka "non-life".BTW the term organic has several different conotations. Howeverm this term used in science usually refers to carbon compounds that originate in biological organisms. Therefore some rocks may actually contain remnants of organic material in them even though they are considered "non-living" objects. Your definition of life is overly simplistic. Many multicellular organisms are composed of many other substances, organic and inorganic, besides cells i.e. proteins, lipids, polypeptides, sugars, water, etc. Are these substinance considered "living" or "nonliving"? How about mature mammalian erythrocytes (red blood cells) which lack a cell nucleus and DNA. Are they considered "alive" even without genetic material in a nucleus or mitochondria and the ability to "reproduce" or more accurately divide? Cells of muscle tissue as well as nervous tissue also do not divide after birth. Myoblast (precve ursor skeletal muscle fiber cells) fuse together and often have many nuclei but cannot replicate. Are they alive?And how do you define cells? Again, can viruses be grouped along with other cellular life. Some virus (though not all) have a lipid membrane which is derived from the host cells they invade and serves the same purpose as a cell membrane in keeping intact the genetic material inside and protecting it from potentially harmful substances outside. However, viruses can only reproduce by canabolizing host cells. Ditto, see above. Not all living organism or the cells they are composed of reproduce. Mules don't reproduce. Assexual and sterile people don't reproduce. Red blood cells and several other different types of cells in the body don't reproduce. I do? When have I done that? I am just saying there is no clear definitive dividing line between life and non-life. That is it. This is what 100+ years of serious biochemical research has taught us. The real question is not how can can life come from non-life but how exactly did life originate on Earth. "Life" comes from "non-life" every second in practically every nook and cranny on this planet. "Life" is composed of organic and inorganic "living" and "non-living" material (I use the terms "living" and "non-living" terms very loosely to make a poignant point here) which is continually recycled over and over again. Actually these are not terms that are used in common occurance in biochemistry journals because they make absolutely no sense. They define, NOTHING on a molecular level. So this is really a moot point. It is ironic because you are quoting from someone who you would adamantly oppose if you really understood what he was saying in this article other writings (that life on Earth originated via natural means and evolved to its present status today). I am not sure what your point is here? Wrong. You really do need to study up on your material before making statements which have no basis in reality. Thomas Huxley was a naval physician and zoologist who won awards for his research in the fields of anatomy and physiology. Huxley infact wrote several papers directly on the subject of cellular biology. Biological cells had first been discovered by Robert Hooke in 1665, 150 years before Huxley was born. This has been commonly taught in science classrooms due to its simplicity and these ease in which this distinction between life and non-life can be conceptualized. As we dig down into the biochemistry details these distinctions blur.This is similar to the way in which we teach grade schools students that all material in the natural world is composed of atoms. Does that mean that there does not exist other entities that are not composed of atoms? Of course not. Virtual particles and other subatomic particles as well as other forms of exotic matter and energy also exist. However, to keep from overwhelming our young pupils with information that they could not even begin to understand until later we have to oversimplify our teaching of science in the classroom. We also have them demonstrate an atom by creating one with styrofoam balls and toothpics. Does that mean that atoms are really composed of discernable particles with distinct solarsystem-like orbits (electrons) which orbit around a central unified unmoving mass (nucleus)? Of course not, this is simply a oversimplified model to get them on the right track of understanding basic scientific concepts. The same is true with your statement that "cells are the basic building block of all life". In reality in order for your statement to be scientifically sound it should read: "All biological systems discovered on Earth to date are composed of cell/cell-like structures and other organic and inorganic material which are capable of temporarily decreasing the local entropy of its system through the changing of matter and energy from one form to another." I am not contesting this. Again you are really not understanding the science behind these natural phenomena. On a molecular scale they are indistinguishable. All science is theoretical. Science is built on theories: Newton's theory of gravity, the theory of evolution, the general and special theories of relativity, atomic theory, Big Bang theory, etc. Furthermore, no one is contesting that abiogenesis is anything but theoretical. I never used these terms and I have not seen anyone but you use this overly simplistic strawman argument. If they are used they are only used as an oversimplification of what is actually occurring i.e. the initial genesis of biological systems from non-biological, inorganic matter, This is a double-edge sword and thus applies as much to you and the rest of the IDers and creationists as it does to those you disagree with. In other words you can't make rational decisions without
substantiated emperical evidence. True scientific theories are developed from and are supported by facts/emperical evidence not the other way around. Whatever floats your boat. No one is making the claim that abiogenesis is fact. Science is just researching the most likely scenario of how life could have originated on Earth (aka Occalm's Razor). Pounding head on wall. NO ONE IS SAYING ABIOGENESIS IS FACT! How can you say out of the left your side of your mouth that abiogensis "may be proven" and in the next sentance that it "has [already] been disproven"? You can't have it both ways. Science takes the middle ground and is saying there is no conclusive evidence exactly how abiogenesis occurred but is still collecting evidence to figure out how. Science does not "prove" things, it provides valid, rational explanations for natural phenomena. There is a difference between these two concepts. Sorry I get a chuckle everytime a creationist or IDer says this. If you have to keep repeating how objective and rational you are to yourself and to us, than it probably means your not being objective and rational. If I learned one thing in life it is this. Don't take yourself too seriously.Have a good night Edited by DevilsAdvocate, : No reason given.Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

I think all of science would agree with the former statement (as none of science can be 100% evoquivacally, unquestionably proven anyways). Science is just trying to find a rational, credible explanation of how life originated on Earth (science by definition cannot defer to the "God did it", as this would stop abiogenesis research in its tracks). It is the latter part that many of us disagree with since these two terms ("non-living" & "living") are highly arbitrary and subjective in the biological fields.Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Sorry I meant to say exactly HOW abiogenesis occurred is not fact.The only choices of how life originated are either a natural scientific explanation or a supernatural nonscientific explanation i.e. 'God did it'. One could also go the middle road and say that God is the ultimate cause but he uses natural phenomena to accomplish his will, however this is scientifically de facto the same as the first choice (attempting to find a natural scientific explanation for the origination of life).Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Are you serious here? Really? Rocks dont decay? Chemically what is the difference between molecules in rocks decaying and the chemical decay of molecules in living organisms?

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

On a molecular and atomic scale what is the difference between oxidation of organic molecules and inorganic molecules in life forms and oxidation of organic and inorganic molecules outside of life forms? The affect is the same on the microscopic level though on a macroscopic level they may be different.Rock's decay at a much slower rate than life forms but they do decay through oxidation (rust), weathering by the elements, and radioactive decay.If I am wrong on this let me know and I will concede.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

I am sorry but I think this point is very relavent. Hyroglyphx is using the term decay as a distinction between life and non-life when scientifically this is not as black and white as he would like us to believe.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

I guess steering off-topic is inherent to a scientific forum such as this but honestly I think my making the parallel between chemical decay at the molecular level between "life" and "non-life" was very pertinent as Hyroglyphx was using "decay" as a property that only existed in living organisms and would distinguish it unequivocally
from "non-life".I still stand by my statement that decay at the molecular level is very similar in both types of objects i.e. oxidation of molecular components (this occurs both in "living" and "non-living" things though at different rates), leaching of water (ditto), breaking down of matter into small bits (ditto), radioactive decay (living organisms have radioactive material as well but sometimes in smaller quantities). Decay occurs in both just at different speeds and in slightly different manners. Yes, at a higher macroscopic level the method by which the above molecular decay occurs may be different (i.e. microbial and enzymic decomposition, etc) but at the molecular and atomic level the end result is nearly the same. Hopefully this makes sense.This is a distinction that Hyroglyphx brought up and I thought it should be one that was not ignored. However, I will cease and desist now and quit belaboring my point so as not to draw attention away from the rest of the abiogenesis thread. Sorry about the inconvenience .BTW Hyroglyphx we are not personally attacking you. This is how real science is conducted through analysis of evidence, debating through peer review (yes, I know not all of us are paid, practicing scientists but I still find the information I learn on this board very educational and valuable), drawing inferences, etc for the end result of rationally determing valid and logically sound explanations for natural phenomena.If you think this is a personal attack than you may want to analyze what it is you are actually saying and see if possibly, possibly you could be incorrect and uneducated on some of the things you say on here and seek to become more educated on some of these topics. I will be the first to admit when I am wrong and have done so many times on this board as I am sure Percy, Cavediver and others can attest to.Edited by DevilsAdvocate, : No reason given.Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Except that you were using decay as one of these qualifiers to distinguish life from non-life. That is called circular reasoning.BTW, all life does not putrify. Do ameoba's putrify? How about bacteria? No. Why? Because only multicellular organisms putrify and bacteriar are the things that are causing the putrification. Therefore your use of putrification aka decay as a distinction between life and non-life is like saying the difference between life and non-life is life. It makes absolutely no sense. Actually I did not originally bring up the topic of radiological decay but yes it is present both in living organisms and non-living things. That was my original point in that at the most basic level decay results in the same end products and thus cannot be used as a distinctive qualifier between life and non-life. You are mixing up terms. Organic matter does not equal life and inorganic matter does not equal nonlife. Organic material is created by the biological processes of living organisms whereas inorganic material is not. Both organic and inorganic matter can be found in and outside living organisms. In other words organic matter is the product of living organisms not the defining qualifiers of what living organisms are. No that is unequivocally so unless you believe in the magical appearance of life out of nothing, no matter but pure nothing. Neither can you be sure of anything else if you call this into question, including your own existence or whether you are on the Earth orbiting an G2 class star called the Sun for that matter. How far are we going to go with this? No, it is just you want everything to be painted in your 100% black and white fantasy world and that is not how science paints reality. I am trying to make the poignant point that the terms you throw about here i.e. life and non-life are not as clear cut as you make them out to be.Edited by DevilsAdvocate, : Missing symbols, replaced with words.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Your exactly correct on this as always Mr. Jack . I think we are mixing up the simplified, colleqial use of the terms 'organic' and 'inorganic' and those used in biochemistry. Even the military uses the terms 'organic' and 'inorganic' but with very different tactical/strategic meanings.Thanks for the correction.Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

I think Phage made an excellent analogy here as to the limitations of using anthropocentric labels to describe natural phenomena. So what is the exact point that the gravel ceases from becoming just a pile and is truley a parking lot? And vice versa. How much gravel can be piled uon each other or does it have to be completely flat with only 1 level of gravel with no piece of gravel on top of another piece of gravel? And at what precise, specific point in time does this occur?Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

I think you are missing the point here. I think everyone can distinguish most forms of life (though not all) from non-life at the macroscopic level i.e. the level we humans observe on a day to day basis without using any type of microscopic instruments. The issue is when we look at life at the nano level (atomic/molecular) there really are no distinguishing features that differentiate the two (can you tell the difference in structure between a molecule of sugar inside a living organism and one outside). Why do we care? Because it is at this level that abiogenesis (yes I am just using this as a label to describe the chemical synthesis of the first molecules of biological "life") occurred.Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Oh great. Who invited Tony to obfuscate an already obfuscated topic on the distinction between life and non-life We only need a panspermia advocate to the mix and our abiogenesis fruit salad will be complete.I give up.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

Our vestibular system (sense of balance and spacial orientation). Though it does more than just "sense gravity". That is a simplistic description of the function of this system.Edited by DevilsAdvocate, : No reason given.

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For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan