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Evolution and theory of conservation of energy

  1. Sep 30, 2014 #1
    Life started from a single cell, right? And now we have countless number of cells on our planet. So is this like new matter being created? So there is more energy on the planet as of now? How is the energy on the planet being conserved? I possibly framed the question wrong, but I hope you understand. Thank you.
  2. jcsd
  3. Sep 30, 2014 #2


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    No new matter is being created; plants take stuff in from the ground and air, use that to create new plant cells.

    Nor is there any problem with conservation of energy, as sunlight provides a steady supply of new energy from outside.
  4. Sep 30, 2014 #3


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    The earth is not a closed system. You are forgetting one obvious source of constant energy to our planet: the sun! Examples such as photosynthesis of plants that provide us (and other animals that we eat) with food should clearly indicate that we have an external source of energy to the planet.

  5. Sep 30, 2014 #4


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    I've moved this to the biology forum. Manraj, you may be interested in the two stickied threads at the top of the forum. They contain a wealth of information and links to evolutionary topics.
  6. Oct 1, 2014 #5
    Q: "Life started from a single cell, right?"

    A: So highly unlikely I wouldn't even consider it.

    Very few species start with single organisms, and such extremely rare speciation events are all dependent on the reproductive barriers that modern organisms can put up:

    "In biology, saltation (from Latin, saltus, "leap") is a sudden change from one generation to the next, that is large, or very large, in comparison with the usual variation of an organism. The term is used for nongradual changes (especially single-step speciation) that are atypical of, or violate gradualism - involved in modern evolutionary theory."

    "Saltational speciation, also known as abrupt speciation, is the discontinuity in a lineage that occurs through genetic mutations, chromosomal aberrations or other evolutionary mechanisms that cause reproductively isolated individuals to establish a new species population. Polyploidy, karyotypic fission, symbiogenesis and lateral gene transfer are possible mechanisms for saltational speciation.[19]"

    [ http://en.wikipedia.org/wiki/Saltation_(biology) ]

    We know that the requisite chemical populations existed (anoxic, reducing highly biochemical productive Hadean/Archean), and there is no reason why evolution didn't proceed as elsewhere: gradually and on large populations.

    Q: "Life started from a single cell, right? And now we have countless number of cells on our planet."

    A: Today's life descend from a LUCA, but it was very advanced. Like above there is no reason to believe that life didn't proceed pre-LUCA as elsewhere: 99.9 % of species go extinct.

    Q: "Life started from a single cell, right? And now we have countless number of cells on our planet. So is this like new matter being created?"

    No, it is like plants grow and food is consumed.

    Q: "So there is more energy on the planet as of now?"

    - There is less energy in the core, as it has been cooling despite radioactive heating.

    - There is more energy on the surface, as today's Sun output 25 % more radiation than the young Sun. (See the main sequence of stars.)

    - The energy bound in bioproductivity depends on the environment, but also on evolved capacities (diversity). The most productive biosphere was perhaps in the Carboniferous, a hot, wet and already well diversified biosphere which a lot of today's kerogens comes from. (Kerogens are the carbon dominated results of biochemical breakdown in sediments, mostly coal and oil.) IIRC the estimates is today's Earth is 70 % as productive.

    Q: " How is the energy on the planet being conserved?"

    It isn't, a planet isn't a closed system but radiates incoming heat to the universe (and latent heat from the planet accretion, and potential energy from gravitational settling, and radioactively generated heat). This is required of a thermodynamic steady state such as our greenhouse atmosphere. The energy is dispersed, and life evolved in order to disperse it faster.

    Originally to rust iron that plate tectonics and erosion released and to reduce CO2 to methane. Then other metabolisms evolved, which modify that a bit re material and energy used. Photosynthesis utilize irradiation instead.

    Today most of the energy influx to the biosphere is from that large, yellow star that dominates the day sky. :D
    Last edited: Oct 1, 2014
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