The Development of Intelligence
It is not obvious that intelligence or the development of more complex species should be expected, following strict evolutionary theory. All species undergo change and mutations. Characteristics advantagous at that time, increase the likelihood of that creature to survive and pass that characteristic to its offspring. Is intelligence anymore important a characteristic than say, having an exoskeleton, or being able to breath both underwater water and on land? If intelligence is so great, why did it take 4 billion years for it to come about? We haven't been getting gradually smarter for 4 billions years, rather it is a very unique characteristic that came about only very recently, and rather suddenly (and may vanish as suddenly, too!)
Given time, will all life-sustaining planets form intelligent life?
No.. Not necessarily, or it may exist in only a very short lived species.
The extreme diversity of life present now and, even more so, represented
over the last 4 billion years of life on Earth, is astronomical. Yet of
all the characteristics ever displayed in all the species to ever live on
this Earth, only one has ever developed the unique characteristic of
advanced intelligence.
Complex life: Just a whimsical byproduct?
When you consider the numbers or look at the total biomass on Earth, simple
bacteria and archaea far outnumber (and out weigh!) more complex life.
In fact, it is this simple life which has so readily adapted and survives
in the largest variety of conditions on Earth today. The most abundant life
on Earth have changed the very least in billions of years. There
is no imperative toward the development of more complex or highly intelligent
species.
Backward Evolution?
When looking at the geological record, species are just as likely to evolve
to less complex forms as to more complex forms. So does
this mean Evolution goes backward? No.. Evolution only tells us species
that can adapt to their current environment thrive, and these circumstances
might just as easily dictate a more complex species to evolve as a less complex
one.
`Reverse Evolution' was demonstrated rather effectively in the movie, `Planet of the Apes'..