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Things that Yoram knows: why should you eat? On the strange connection between evolution and thermodynamics

Why should you eat? RK asks following This video The story is about Jani Perhald, an Indian monk who fasted for 75 years of meditation and feels great

eating. From Jumpstory
eating. From Jumpstory

Well, Rak, seemingly the standard answer given to us by our mother when we refused to eat should suffice: we eat to grow and for energy. But what to do, even mother is wrong sometimes. You don't eat to grow - only a tiny part of the tens of tons of food and drink that we put into our bodies during our lives will stay there. And what about energy ie work and heat? Our friend Jani could reason that continuous meditation is not really work and in hot India there is no need to burn sandwiches to keep warm.
So why do we still eat?

Living things are wonderfully ordered and coordinated systems and this order is an enigma. Thermodynamics, which is the science that deals with the circulation of energy, has two basic laws. The first is the conservation of energy: energy does not appear from a source and does not disappear, the second law states that energy gradually decays. "Waste" of energy means that it is more difficult to produce work from it. In order for us to use energy to drive a car or transmit and receive information on a telephone, our world needs to be orderly and organized. Just as order in a room means non-uniformity (all the clothes in the closet and all the books on the shelf), order also appears in nature as "gradients", that is, as non-uniformity in the density of energy or matter. When the world became "messy" meaning when the energy turned into heat which means random movement and this heat is spread uniformly we will no longer be able to use it. The second law of thermodynamics states that in any isolated system disorder or in scientific language entropy must increase. An isolated system is one that neither receives nor gives matter or energy to the world around it. If Jani Perhald did stop eating and drinking, then his body has become a closed system that must be messed up. When we eat, we first of all destroy order: large and orderly molecules enter, burn and leave as carbon dioxide gas that spreads everywhere. Ludwig Boltzmann, the father of statistical mechanics already stated in the 19th century that "the war of existence among living beings is not about the raw materials, these are air, water and earth and they are all easily available, nor is it about energy that is abundant in the form of heat. The fight is over entropy that becomes available in the transition between the hot sun and the cold earth."

The second law of thermodynamics has always been a perplexing matter for biologists whose systems insist on getting along, and even evolving over the generations towards more order and organization. It is possible to somehow calculate and show that every living being produces enough entropy in its life to satisfy the requirements of the second law, but why would such orderly structures grow at all in a world that is getting messy. The law of increasing entropy was used by the opponents of evolution because the development in the living world: from the simple to the complex seems to contradict the natural direction of flow from the ordered to the entropic. How is it possible for particles to suddenly "decide" to behave in a coordinated and harmonious way, just as the molecules in a living cell behave? The laws of thermodynamics as they were formulated in the 19th century to understand the operation of steam engines and as they are interpreted by students to this day refer to systems where biology does indeed seem strange to the point of embarrassment. But when you expand the scope of the second law to systems through which a flow of energy passes, it becomes clear that the complexity of life is not so strange. A simple system that demonstrates the principle is a Bénard cell, a layer of buffer liquid between a hot plate and cold air. Heat passes through the liquid from the hot plate below it to the air above it. When the temperature difference is small, the system behaves as we would expect: the lower liquid layer heats up and the heat slowly seeps upwards (conductive heat transfer). But when the temperature differences increase further, a strange phenomenon occurs: orderly and stable circular currents are formed: thin layers of liquid take over the transfer of heat and do so with maximum efficiency.

The seemingly improbable happens - an astronomical number of particles simultaneously create a coordinated movement.

Bénard cell: ordered flow lines (white lines) that appear in a cell containing a hot liquid (in red) with a cold liquid above it. Source:, Wikimedia

When heat flows from a hot to a cold area, the entropy increases and the more heat flows, the faster the general entropy rises, the orderly and coordinated structure not only does not contradict the second law but is its result: a system organizes itself when this is necessary for the rapid production of disorder in the environment. The atmosphere provides us with additional examples of orderly structures that arise by themselves when there is "a lot of order" to spoil. When warm and moist air encounters cold and dry air, a tornado is sometimes formed, meaning a wonderfully organized flow of air that causes energy to flow quickly and eliminate energy differences. In a similar way the formation of the great ocean currents can be understood. Life, according to this description, is a "tornado with memory" meaning a stable, ordered system through which a flux of energy and matter flows in a manner that effectively increases the general entropy. The flow of energy to living systems originates from the temperature difference between the sun and the earth and between it and space. Measurements of the energy transformations in different ecosystems have shown that the richer, more diverse and "mature" (that is, more organized) the ecosystem, the more efficient the transition process of the energy flow from orderly radiation to messy heat. The hereditary memory allows the system to find the steady state without reproducing the random fluctuations that lead to it in stationary systems such as a vortex or a sea current.

The second law is considered the most pessimistic of the laws of nature. The entire universe progresses over time to equilibrium, that is, to an equal distribution of energy in space as heat. "Equilibrium" is a physical term that in biology means death. The new understanding transforms creativity: life is not a rebellion against the second law but its result. Life in its harmonious complexity is nothing but a means to sense the flow from order to anarchy.

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3 תגובות

  1. Does it follow from this that humanity is actually the only vortex that nature did not take into account? Really want to believe we're special?

  2. The simple answer to the question is that life is energy consumption and food is the source of energy,
    The question remains unanswered
    Or an explanation is how Jani Pearlhead and his ilk manage to deceive their believers,

  3. So why should you eat?
    Could it be that I missed the simple answer to the question in all the text?

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