3. Origin of Life
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  1. Concept of life

   Once we accept Earth as the one and only habitable planet in the Solar System, what arguments have we to say that? In many lectures people asked me: Life is only as we know it, but could it be different kinds of life? So we must know what life word means before answer these questions.

    If I am using a microscope and see a little black thing, first I need to know if it is alive or dead. And if, after hours of watching it, the black thing doesn’t move, the logical answer is that it is not alive. Why? Because life involves activity. And if a living being is a material being, and has activity inside its body, certainly he needs to spend energy. Where he could obtain that energy? And it obtains it from its environment. Therefore, a living being must be a material being, with activity and capable of obtain energy from its world. It must use the energy for growing up and for reproduce itself. After that, we can consider the rest of questions about life.

    A physicist knows about the different types of matter. First, we have 92 elements from the periodic table, all of them stable ones. We can start with an element of only one particle, its nucleus, the hydrogen, and finished with the uranium, which has 92 positive particles, but a number of 235 particles inside its nucleus. And there cannot be half-charges, so we only have the elements obtained by one, two, three, four, five or 92 charges. Also, we know about elements and their properties, and we know, as example, that helium doesn’t reacts against nothing. So, helium is not suitable for life. Other elements, as gold or platinum, have similar properties, so they are also useless for life.

  A. Answer by clicking one of the letters: a, b, c. (If the letter takes the red color response is correct)

  1. Life appears when there is

    a. calm
    b. activity
    c. rest


  2. A material being with activity spends

    a. energy
    b. fuel
    c. diesel


 3. A living being obtains its energy from

    a. a gas station
    b. the space
    c. the environment


 4. How many types of matter exist?

    a. 80
    b. 90
    c. 92


 5. What element has 92 positive charges?

    a. uranium
    b. gold
    c. platinum


 6. Which one is not suitable for life?

    a. Iron
    b. helium
    c. hydrogen


  2. Stages of matter

   Each element can be found in three stages: solid, liquid and gaseous. What is a living being? A solid? For a physicist, a solid is a crystal. For example, a quartz crystal or a pyrite crystal. But a crystal has no flexibility, it cannot react with its environment without being destroyed. For example: a salt crystal reacts with its environment, but it slowly melting itself due to humidity. It is impossible for it to obtain energy from the environment and maintain its integrity. A snow crystal or a snowflake melts with hot temperatures and humidity. So, due to these reasons, life cannot be based on a solid state; the existence of a living crystal is impossible.    For a physician, the perfect gas is he one which has not structure. But that gas cannot be part of a living being, because a living structure needs a structure, a body. Maybe this would happen in a science-fiction story, where a race of aliens could be pure energy entities and don’t need a spaceship, but this is only a fiction, because energy hasn’t got stables structures and is dissipated in space.    A physician says: only inside a liquid state can a living structure take form. A cell is a drop of liquid with a semi-permeable membrane, through which it can interact with its environment and obtain raw materials. And this is the first stage: we need a liquid, one that will be abundant, because if it was liquid platinum, it would be impossible to find a living environment.

  B. Answer by clicking one of the letters: a, b, c.

  1. How many stages matter has?

    a. three
    b. four
    c. ninety-two


  2. For a physician, a solid is a

    a. crystal
    b. gas
    c. flexible body


 3. If a crystal reacts with its environment it is

    a. maintained
    b. destroyed
    c. preserved


 4. Gas has no

    a. stability
    b. life
    c. structure


 5. There only can be a living structure in a

    a. solid state
    b. liquid state
    c. gaseous state


 6. A cell is a drop of

    a. solid
    b. gaseous
    c. liquid


  3. The reproduction

   But finally we must ask the most important question: how can be explained multiplication and reproduction of life as an activity? Because it is a wonder when it is explained, although we are used to it.

    What is a hen’s egg? Someone could say: 70-80 grams of jelly, without a conformed structure. But if you apply a suitable temperature, a small, colored coffee spot appears. In a few days, a circulatory and a nervous system started to conform. Later, a small heart starts to beat. With a couple of days more, the digestive tract and a weak skeleton are also conformed. The eyes appeared, and in only three weeks the chick builds itself, from a lonely cell to a million of them, and without external help. Three week later, the chick breaks the shell, jumps outside and starts to feed. If that would be told about a university that is putted on the ground and started to build itself we will say that it is only a tale, a fantasy, and it is impossible. But a chick is far more complex than an university.

    And in the case of a human being a cell grows until create a full adult body, with billions of cells. How can it do it? Only because genetic codification, which needs molecules with thousands of millions of atoms, exclusively based on carbon, the only element which can do it.

     So, for physicians and biologists, life can be based only in carbon and in liquid water, because this is the proper environment to develop carbon’s chemical properties. This is the starting point scientists have to argue about life in the Universe, or at least here on Earth, where these conditions are happening since 13.500 million years. We don’t know where, when or how the first cell appeared, but that is the origin we frequently accept.

     (Original text by F. Manuel M. Carreira S.J. Astrophysicist and theologian)

  C. Answer by clicking one of the letters: a, b, c.

  1. A hen’s egg, how much can weight?

    a. 50-60 grams
    b. 60-70 grams
    c. 70-80 grams


  2. The small, coffee colored spot is in the

    a. white
    b. yolk
    c. egg-shell


 3. How many cells has a chick?

    a. hundreds of millions
    b. thousands of millions
    c. tens of millions


 4. Could an university grew by itself?

    a. no
    b. yes
    c. it could be possible


 5. The grow of man is produced by

    a. a fusion of molecules
    b. a mixture of cells
    c. genetic codification


 6. Life on Earth is only based on

    a. carbon
    b. gold
    c. platinum


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