|
Fact |
An observable phenomenon |
Either valid (true), or invalid (false)
Verification occurs by means of replication, which
simply means that the phenomenon is observed by more
than one person, or by the same person more than
once. |
Evolution is a fact that has been observed by many
both in nature and in the laboratory. Organisms
change (evolve) when their natural environment
changes.
|
Global warming is a fact that has been observed by
means of temperature measurements over the planet
for many years. |
|
Theory |
An explanation for the occurrence of observable
facts. It tells why and how the facts come to
exist, as well as how facts go together, including
how one can cause another (which helps us make
predictions).
|
Theories provide a basis for predicting what will
happen, and they are either confirmed, or
disconfirmed preferably by means of controlled
experiments, ones that test the predictive power of
the theory.
|
A Theory of Evolution offers an explanation for
how evolution occurs.
The theory that was offered by Darwin was based on
the concept of natural selection, which says that
organisms evolve in response to their natural
environment based on the survival of those who are
not killed by the changing environment (what is
often called "the survival of the fittest to
procreate"). In other words, those organisms
that are killed by the changed environment do not
procreate, so their genetic inability to survive is
not passed on to the next generation. On the
other hand, those that are not killed by the changed
environment do procreate and pass along their
genetic ability to survive the changed environment.
So changes in the environment cause the organisms to
evolve (change).
There are other
theories of evolution that have been proposed,
including some based on dna and genetic changes
produced by the environment, or random mutations.
|
Theories that explain global warming look at
external, natural phenomena, including such things
as changes in the sun, climate cycles on earth, and
byproducts of human activity (mostly the increased
presence of carbon dioxide in Earth’s atmospheres
holding in heat). |
