The major points in this chapter may be summarized as follows.
- We don’t know where life started, but we do know how it developed once it took root on this planet.
- Evolution, meaning change over time, is a fact. Natural Selection is a theory, and it very satisfactorily explains why evolution occurs.
- There is a high probability that life exists wherever conditions permit, in likely countless billions of habitats throughout the universe.
- Life’s history parallels that of the universe in its change from simple to complex, because the same laws of physics govern the behaviour of both.
(A postscript to this chapter titled Origin Theory Modifications is to be found at the end of this part.)
- For an excellent review of life’s evolution through its four billion years of development, read Vital Dust (op. cit.) by Christian de Duve, a Nobel Prize-winning biologist. de Duve traces life’s four billion years of development on this planet from its chemical beginnings, through its RNA and DNA encodings, to its current status. His text contributes the kind of understanding that should be possessed by all who make decisions that bear upon life’s future.
- In particular, the second law of thermodynamics. This law states that the total amount of disorder (also known as entropy or complexity) in a closed system (for example, the universe) can never decrease.
To understand entropy, it may help to consider a handful of black marbles shaken into a box containing a handful of white ones. The two mix, and the marbles become disordered, their arrangement “complex.” It takes energy to separate the black and white marbles and return this “system” to “simplicity.” Thus, the disorder of a complex system can be decreased but energy is required, and this energy must come from some larger system. In the example just given, the energy comes from the food eaten by the person separating the marbles. In turn, the energy in the food came from an even larger system—our sun (via photosynthesis), whose energy in turn came from that introduced at the universe’s beginning (through the singularity that opened into the Big Bang).
But, the universe is the largest system we know. It is a closed system (as far as we can tell) and energy cannot be taken from “outside” (if such a place exists). So the universe becomes more and more disordered each second as innumerable events occur everywhere. It becomes more complex, its entropy is ever increasing, and it must forever continue to become so, because there is nowhere (again, as far as we know) from which can be taken the energy needed to order it again.
Subsystems within the universe can be made more ordered because they are open systems, and energy can therefore be taken from elsewhere in the universe’s stock. Life does this organizing, for example when it changes complex food molecules into simpler ones before recombining them in ways useful to itself. Many other processes also reduce entropy, for example when sunlight or lightning break water into its constituent hydrogen and oxygen molecules. But the net result of any kind of organizing is always an increase in the universe’s complexity, because the energy exchanges that are involved all release electromagnetic radiation (usually in the form of heat—think how hot a person would become were they to quickly sort ten thousand marbles, for instance). This energy release eventually heats (i.e., agitates) atoms somewhere, and adds disorder. In other words, with each exchange the total quality of the energy is irreversibly degraded, increasing the total complexity of the universe.
Life started simple and is becoming more and more complex through the addition of variations and adaptations to what existed earlier. In this manner, its evolution parallels that of the universe.