Falsifiable Theories, Speed of Evolution and Diversity of species
What is evolution? The standard definition in science is:
- A change in the relative frequency of alleles in the gene pool
of a population.
- A change in the adaptation norm of a population.
- A change in the diversity of populations of organisms via speciation.
These changes take place over time
. The amount of change is dependant
on the amount of time and the change in the environment
. The theory of
evolution claims that these things change in a population because of
environmental factors. A falsifiable test would be to take two groups
of fruit flies
, and change the environment of one, but not the
other. The allele
s will change. The adaptive norm will change. Given
time and genetic separation (A LOT of time), these two groups will become
different species. These are easy things to test, and they have been
Speed of evolution
It is hard to judge the relative speed of something without knowing
the entire process. Claiming changes over 1000 years has a very
different view if one believes the Earth is 6000 something years old
vs. 4,000,000,000 years old. The radioactive dating of rocks is an
accepted practice. Given a known rate of decay from one element to
another it is possible to make estimations of the age. These
estimations have been proven to be accurate.
So how fast is evolution occurring? There are evolutionary processes
that take millions of years. Others take less time.
Corn has been
bread from its original grass over a few thousand. Evolution happens
with speed according to how fast the environment is changing - as
does extinction. The mass extinctions of the past have caused great
spurts of evolutionary change because many species went extinct and
lots of ecological niches were opened up. Humans have been changing
the environment of the planet for a few thousand years, and rather
quickly at times - is it any surprise that species are changing quickly
along with that?
Diversity of Species
And why shouldn't there be a great diversity of species? There are
a great diversity of different ecologies. In the Santa Cruz
mountain range there are species that can't survive on the sunny side of
the valley, and others that have adapted to it, yet can't survive in
the shaded side. There are different thousands if not millions of
variables for a particular micro-ecology and different species will
be best suited to each one of those. A polar bear couldn't survive in
the same places that a grizzly bear does. Different combinations of
plants surviving means different animals surviving. Even though a
species of plants may be able to live in a climate does not necessarily
mean that it can survive there - if its form of pollination and seed
dispersion does not work. Likewise, even if an animal can survive
in a climate, its food source may not be able to.
One good example
of this is the humming bird, bees, and the flowers. Two species of
flowers - identical in all aspects other than color. One is red,
the other is blue. Hummingbirds are attracted to the red flower,
bees attracted to the blue. While the flowers can grow in either
climate, only the red ones grow where humming birds and no bees are
and only the blue ones grow where bees are with no humming birds.
Diversity needs no explanation other than this. It has predictable
consequences too. Left to nature, if you plant the red species
where there no humming birds, after a generation of flowers goes
by, they won't reproduce and flourish.
The above gives adequate explanation for what is happening. What
else could be happening?