Is Evolution a Certainty?

Some Basic Considerations:

(1) Population: If an organism has more born offspring than parents, then the population will increase.  

(2) Resources: If the available resources needed for an organism to survive doesn't change, then, as the population
     increases there will come a time when the resources available will not be able to support all the population at the
     same level as before.

(3) So: At this time the population will experience a lowering of the "standard of living" for the whole population or 
     certain part of the population will use a greater portion of the resources than another part.
    Eventually there comes a point where the "standard of living" is so low that life is not possible for all.
    Some will likely be more able to use a greater share of the resources and live long enough to produce surviving offspring
   and others will not. 
   The factors that will determine the survivors is one of the main concerns of evolutionary scientists.

This is the logical basis of Evolution and Natural Selection.
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Some broad factors that determine who lives:
- Environmental Factors: Examples: Climate and weather changes that affect things like food sources, predator population, parasites, disease, social conditions.
    You can likely think of other Examples.
- Environmental Accidents: Examples: Organism happens to be in places of unexpected dangers such as volcanoes, hurricanes, earthquakes, meteor strikes, landslides, floods, wars by other species, wars within a species.  Some call this luck.  Again you can think of other Examples.
- Genetic makeup of the organism.

If the environmental conditions are the same for all, then the genetic makeup of an organism becomes the dominant factor.  Those with the appropriate genetics to be able to cope better in that environment and can produce offspring that will live long enough to produce offspring that will live long enough to produce their own offspring will be what is called "the fittest". 
The selection of organisms that cope and reproduce through the generations will result in organisms with genetics that become better adapted to their environment.  Those that have the genetics to cope with changes in the environment will also have a better chance of surviving.
For natural selection to work requires variation in the genetic makeup of the organisms, so that the organisms aren't all the same.  These variations produced in numerous ways are called mutations.

This applies to all organisms from viruses and bacteria to plants and animals, including humans.  
Knowing all this, Humans have the potential to change the environment and genetics to control evolution and not be a total slave to it.
Artificial selection in domesticated animals and plants is an example of this control.

Because of the 3 basic considerations mentioned at the beginning, anything that reproduces, and where there are limited resources would be subject to evolution and natural selection.  Some possibilities:  To Life anywhere (on earth or anywhere else life may be found), to galaxies, to universes.  You can think of other possibilities.

Evolution and Natural Selection are inevitable.

A simple example of the first 2 basic considerations:
In most species the population tends to increase exponentially -- this is limited drastically by the resources available to the species -- the resources tend to be constant.  This is where genetics makes a difference.  The following assumes a couple will have 4 children in each generation.  Also the following assumes that the parents die as soon as offspring are born -- in other words this is a very, very conservative example of the power of population increase compared to resources -- shows how quickly evolution can come into play..

Evolution is determined (natural selection designed) by the environment and the also the laws of Physics and Chemistry and is also dependent on chance happenings such as mutations.

O. Hooge, B.C., Canada
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