Expert: Jeffrey Eldred - 10/4/2009

Question
QUESTION: Sir,
   Why there are two kind of things in this world -living things and non-living things. When everything is matter and energy, why living things are different from non living things? Living things move, eat, think and act on thier own while non living thing are without consciousness. Why dont non living things evolve? Why dont they gain consciousness? Living things protect themselves when something tries to harm them because they have to protect their bodies for the survival? Why doesnt a stone try to save itself when it is crushed?

ANSWER: (Links are denoted by [x] in the text and are a reference to the URLs at the bottom of the page).


"Why there are two kind of things in this world -living things and non-living things. When everything is matter and energy, why living things are different from non living things?"

Things and the world don't separate so neatly into living and non-living things as you would think. From your description it sounds like you are using the biological definition of life, found here[1]. There are organisms which are harder to classify, like viruses, who are some basic and so parasitic that they rely on other cells to do much of the functions of life for them (especially metabolism, some reproduction and growth). In one light they are a clever organism that shows how little life actually requires, in another light they are little better than a toxin which amplifies in intensity as it propagates through a living system. I'm not a specialist in viral biology, but from what I understand there are several forms even simpler and less life-like than viruses including things called viroids, satellites, and prions. Actually, depending on how you define it, scientists may have already created artificial life in a laboratory[2].

Physics also has some things to tell us about life. The second law of thermodynamics states that entropy always increases when systems interact in a "closed system". This means that rather having hot and cold you will get mild and mild as time passes, and rather than having salt and water you will get salt-water as long as the energy remains the same. Earth is not a closed system however, and we constantly have energy pouring in from above (the sun) and below (the heat of Earth's magma center). In order to function, all living things need to use up some of this energy in order to resist entropy which would destroy their form by mixing it up. You can actually measure the amount of energy dissipated this way, and thick rainforests have the highest reading on the planet because they are so dense with living things. Kleiber's law tells us the size of animals doesn't scale directly (you don't have elephants the size of mice or insects the size of an albatross), but have a constant metabolic rate per weight between all life forms which might be able to attributed this entropy requirement in cells[3]. A Belousov–Zhabotinsky reaction is non-living chemical reaction that resists entropy - Instead of reaching chemical equilibrium (AB + C -> ABC) it oscillates between three different states over time (AB + C -> BC + A -> CA + B -> AB + C), but requires energy to do it[4]. This cyclic process remains a basic unit of information processing that can be used to build up much larger things.  Much of this discussion of the physics of life comes from an enlightening presentation by Peter Weightman, who helped me understand the research in this complicated area. Unfortunately his talk is not available online, but he is a professor at the University of Liverpool and perhaps he has some further recommended reading or is giving a talk in a location that you can get to[5].

Biology gives us the sufficient conditions for life, self-directed self-preserving self-replicating behavior, conditions with which you know you have life. Physics gives us the necessary conditions for life, resisting entropy, without which you cannot have life. The grey area comes when you have something that resists entropy but doesn't yet have all the traits of the biological definition.

Life is a proper sense usually has to go beyond reacting to an influx of energy - it has to store its own energy in order survive changes in the environment and to create more things with its surplus energy. Life also has to be capable of rather sophisticated structures. This is mostly why life is based off of carbon, oxygen, and hydrogen - the covalent bonds allow for a large variety of modular structures and glucose structures (and other carbohydrates) are used as an energy source.


"Living things move, eat, think and act on their own while non living thing are without consciousness. Why dont they gain consciousness?"

The answer is quite simple, non-living things don't have consciousness because the biological processes that make up life are the same that make up consciousness. If you get badly injured in the head you can lose consciousness for a time being, you can forget things previously accessible to your consciousness, or you can have a mental operation made permanently impossible. The obvious conclusion would seem to be that what occurs with your senses, your memory, you thoughts, and your feelings - known collectively as consciousness - is the result of physical-chemical-biological processes in the brain. Some people find this fact depressing, but this doesn't have to change how you feel about your consciousness, it just explains how it operates and what could change its nature. If I told you there was something purely mystical and magical about how the brain and the mind were connected, it would still be some sort of mechanism at work and one should feel the same about the idea of a process behind consciousness.

Given the gradual continuum of life from proto-cells to intelligent humanoids, the only sensible way for me to think about consciousness is that it is also gradual and not an "all-or-nothing" type of thing. If we think about our senses as part of consciousness, we have to agree that there are organisms with different senses and organisms for which it is ambiguous as to whether what they have counts as a sense. One might counter that the center of the brain that processes visual images in the brain is used instead for touch and hearing in blind people (which is true) and therefore consciousness is more fundamental then senses, but then we would also have to agree that there are those with different abilities to formulate images and we can impair this ability with drugs or medicine. Obviously, memory is not perfect or consistent either.

Since we are on the subject of consciousness, I thought I would throw in some interesting findings in computer science and neurology: Scientists can use a brain scanner to predict a simple action before it is performed by a person, before that person is aware of the action that they are going to take, before that person can consciously direct themselves to perform that action[6]. Computer scientists are running programs to simulate the brain of a rat through reverse-engineering[7][8] as well as artificial neural networks, built from the bottom-up[9]. A supercomputer is planning on competing against humans in the trivia game, Jeopardy, using traditional (not neural network) computer algorithms but with a high level of artificial intelligence[10].


"Why don't non living things evolve?...Why doesnt a stone try to save itself when it is crushed?"

For something to evolve you need Variation, Selection, and Heredity. In brief, there is a variety of a certain trait and when animals struggle to survive and mate, the number remaining is dependent on that trait (Taller giraffes are better at eating leaves so more survive). Those remaining pass on highly similar, but not exactly the same, traits to the next generation (Tall adult giraffes raise tall children). The heredity of these traits allows the cycle to repeat until you have forms better and better at operating in the environment.

Non-living things have no Heredity and a much smaller degree of Variation and therefore are not capable of evolving. Perhaps the best term for what occurs instead is Uniformitarianism[11]. Stones are generally not rounded and smooth, but if you look at stones inside a river or ocean, quite round and smooth stones can be found. If one didn't know much about stones, might suppose that the stone is adopting a defensive shape to resist the water or that rounds stones prefer to live in the water. What happens, of course, is that the water erodes away all the protruding and rough edges and only a round, smooth form is left. It wouldn't make any sense to talk about the stone protecting itself, because there is nothing that actually causes the stone to prefer to be in one state or another, it's just the consequences of what happens to it. Indeed, if you went down the river to the delta where the eroded soil is deposited, you would find it arranged with the heaviest soil on the bottom and the lightest soil on the top. This sorting comes from the variation in the weights of the soil and the different effects that the river has on it, but nothing more than that.

The stones don't move to avoid rivers and don't form themselves before entering the river because they lack the variation. There is no stone that can do these things even a little bit by itself, so there is no way they can get better at it even as the environment changes the stones themselves. If you study evolution you will find that some traits don't show up until a certain point in biological history because there are unrelated traits needed to develop for the new trait to function.

More importantly stones can't build on the selection of past stones through heredity. They are made of energy, but they don't store chemical energy the way living things do. There is only so much a stone can get polished before it is all eroded away. There is no way a stone at the bottom of the river can pass on it's traits to the stones at the top of the river, so that it might pass through with more of its size intact.

Living things not only have all three features of evolution, but have a way of storing the energy which is necessary to accomplish this and the framework for storing sophisticated information that is only found in biology. This is where the discussion of biology, chemistry, and physics of life comes in - an exciting area of research that grows every day.


Links:

[1]http://en.allexperts.com/q/Biology-664/2009/3/Definition-life.htm
[2]http://www.livescience.com/strangenews/090111-creating-life.html
[3]http://en.wikipedia.org/wiki/Kleiber%27s_law]
[4]http://en.wikipedia.org/wiki/Belousov%E2%80%93Zhabotinsky_reaction
[5]http://www.liv.ac.uk/~sc35/
[6]http://www.sciencedaily.com/releases/2008/04/080414145705.htm
[7]http://bluebrain.epfl.ch/
[8]http://zikkir.com/science/4805
[9]http://www.neuralsimulationlanguage.org/about.html
[10]http://www.nytimes.com/2009/04/27/technology/27jeopardy.html
[11]http://en.wikipedia.org/wiki/Uniformitarianism_(science)

---------- FOLLOW-UP ----------

QUESTION: thank you sir,

Sir as the science believe that the life has come out of non living things? How did that actually happen? And why that doesnt happen today and cant be done in laboratory? Also sir, why scientists cannot make a human being in lab, if they know that everything that a human body is made up of is some complicated machines make up of different chemical compositions. Also why cant scientists bring back life in a dead body when they know that life is nothing but a collection of processes taking place in human body(like digestion, respiration etc). When they can make humans respirate artificially, why dont they let the machines perform all the functions in a dead body so as to let it survive forever?

Answer
"as the science believe that the life has come out of non living things? How did that actually happen? And why that doesnt happen today and cant be done in laboratory?"

Scientists do tend to believe that life has come out of non living things, but the exact mechanism is not completely clear as of right now. The field of study based on the origins of life is called Abiogenesis[12] and the aim is to see if the connection can be made. This is a much more difficult and much more controversial field than the evolution of life. From the time there exists single-celled organisms with DNA and onward, we understand the science quite well and it is in the domain of evolutionary biology. Before that science doesn't have enough evidence for any one particular theory to claim to know that it is the absolutely correct theory, and that it won't be overturned or heavily modified by another one. So as to preserve its legitimacy and authority, science tends to understate what it knows in areas of new research so that people can trust them when they do come up with a conclusive answer. There are some religious people who claim that science will never understand the origins of life, and I think such claims are ignorant of the promising research going on right now.

The study of abiogenesis seems to attempting to answer two questions in its quest to connect life to nonliving things. The first question is "What is the most complicated nonliving organic chemicals that existed when life started to appear?" Biologists have to work with geologists, climatologists, and exogeologists in order to figure out exactly what those conditions were, of which is the subject of a lot of research. The Miller-Urey experiment was the first of many experiments conducted which attempted to recreate these conditions and detect the chemicals that resulted. Some configurations generate a lot of organic molecules, amino acids, and hydroxylated molecules which are components to things like proteins and enzymes, but don't themselves make up living organisms. You also have to recall that the environment in which abiogenesis would have actually occurred would be over a much wider space for a much longer time (The Hadean Eon, which lasted about 0.8 billion years). It may be that there are more unlikely, more complicated formations which wouldn't show up in the laboratory, but would have showed up somewhere on the earth that was necessary for life to start.

The second question is "What is the simplest form of life that can be made out of reactions between chemical compounds?" The term for such very simple life is sometimes called a protocell. The "RNA world hypothesis" postulates that genetic information (heredity) came before metabolic processes (storing and processing energy) and the researchers from the link [2] were conducting research to advance that part of the field. The other main theory is the "Iron-sulfur world theory" which postulates that metabolism came before genetic information. There are other minor theories as well and an active effort to incorporate information from both theories. The important thing to understand is that this is a field that has more "leads", theories that are yet to be ruled out, than it has "dead-ends", obstacles which make theories seem impossible.

Abiogenesis can allow for whatever created life in the past to continue to be working today. Doubtlessly the environment would be different, but it is certainly possible that things are similar enough for it to be the case. I already mentioned how we have discovered a number of things that we are unsure how to classify. The thing is that it would occur so slowly that we wouldn't actually get the chance to see it happen. Also, anywhere on the world that there is already life we wouldn't be able to determine whether we were seeing something semi-living coming from the structure of living things or non-living. If we look anywhere in the world where there isn't life than we already know the conditions of that spot doesn’t tend to produce life, so that would be no surprise.

If you feel you would like a better account of Abiogenesis, I would recommend sending some questions to AllExperts in the fields of Molecular Biology[13] or Biochemistry[14]. I do not doubt that they can give you much more detail than I could.


"And why that doesnt happen today and cant be done in laboratory? Also sir, why scientists cannot make a human being in lab, if they know that everything that a human body is made up of is some complicated machines make up of different chemical compositions."

There are a lot of interesting things that scientists can do that isn't quite making life from scratch, but is awfully close. I had previously mentioned the RNA experiment [2], which was something similar to life from basic elements. Another thing biologists can do is take the genetic information out of a bacterial or viral cell, break it down into more fundamental components and put it into a new cell[15], thus "reprogramming" it to behave in a different manner (such as breaking down sewage, detecting chemicals, producing chemicals). By manipulating stem-cells and unfertilized eggs, scientists have achieved cloning[16] in non-human animals (because of the high rate of genetic defects and early deaths in cloned animals, it remains illegal to clone humans). So the more scientists work with biological structures already in place in an organism, the more sophisticated things they are able to produce. As elaborated below, the human body is very very complicating and wouldn't keep in the same state while you were attempting to build it from elements.


"Also why cant scientists bring back life in a dead body when they know that life is nothing but a collection of processes taking place in human body(like digestion, respiration etc)."

When a body dies, it immediately starts to undergo chemical decay all over which destroys the cells that run the body. This decay occurs all over the body and scientists/doctors would have to fix that in order to get the body working again, but it occurs so fast and would be so impossible to reconstruct that at that point it is too late to do so. When a dying body is "brought back" with cardiac resuscitation it's because doctors managed to get it functioning enough to stop decaying and start repairing again but there is a very narrow time limit in which this is possible. Once the body decays past a certain point the biological information upon which the body was constructed doesn't exist anymore so they wouldn't even know how it is supposed to be put together. It's one thing to know that the brain is made of neurons; it's another thing to know where all the 15-33 billion neurons are and where each of 10,000 synaptic connections, per neuron, were wired. Scientists simply don't have the technology that scans at the level resolution. Even if they did, they cannot manipulate stem cells with that level of precision and with an environment in which they naturally die. There are a lot of neat things that can be done with stem-cells that aren't quite so complicated, but in many countries there is legislation that forbids researching with them[17].

This means that people who previously had themselves cryogenically frozen very likely wasted their money, because even in the future it will be impossible to recover all the lost biological information and bodies are not perfectly preserved as they are sit frozen. The situation is different, however if you manage to preserve the state before any decay, have a means of keeping the preservation, and have a way of bringing it back to function without damaging it. There are some creatures which appear to be dead (it is very hard to detect biological functions and the body is highly resilient) and this is called cryptobiosis. Scientists have recreated this feat in non-human animals that don't have cryptobiosis and this is called suspended animation[18]. This is being studied to improve surgery, transport vaccine, transport donor organs, prepare for long-term space missions, and of course, with the long-term goal of cheating death. It's really amazing, cutting edge research, but I don't know think we will ever "bring back" someone who died unattended.


"When they can make humans respirate artificially, why dont they let the machines perform all the functions in a dead body so as to let it survive forever?"

As I said before, the decay gets in the way of a body remaining a body. The better way to think of things like artificial respiration, heart transplants, and insulin injections is to think of them as the prevention of a single biological problem. You have to perform the operation in between when the problem occurs and when it destroys the patient. Someone could theoretically have a lot of their body parts replaced and body chemicals regulated by medicine, and I think we will see the limits of that pushed in the future. But each operation is another possibility of a failure and there are some problems which we don't yet know how to solve. We understand more and more about the effects of aging (we subdivide it into cardiac problems, vitamin deficiency, chronic pollution, cancer etc), but a great deal of this we just don't have the understanding or technology to beat and may not for quite some time. In some respects, what happens when people age is a much slower form of that un-retractable decay that I was saying occurs when people die.

Needless to say, there are a lot of exciting things happening in science everyday, and the best way to follow along is through science news[19][20] or blogs[21][22].


More Links:
[12]http://en.wikipedia.org/wiki/Abiogenesis
[13]http://en.allexperts.com/q/Molecular-Biology-1353/
[14]http://en.allexperts.com/q/Chemistry-including-Biochemistry-1355/
[15]http://en.wikipedia.org/wiki/BioBrick
[16]http://en.wikipedia.org/wiki/Cloning
[17]http://en.wikipedia.org/wiki/Stem_cell_controversy
[18]http://en.wikipedia.org/wiki/Suspended_animation
[19]http://www.sciencedaily.com/
[20]http://news.bbc.co.uk/2/hi/technology/default.stm
[21]http://scienceblogs.com/pharyngula/ (you can go to http://scienceblogs.com/ for blogs by other people, I just like the atheist-biologist PZ Myers)
[22]http://blogs.discovermagazine.com/badastronomy/ (similarly, there are more blogs at http://blogs.discovermagazine.com/ but Phil Plait does a great job with astronomy)