Why hasn't all life evolved into intelligent beings?

Question

What I mean, is fully human-like. If the human ancestor's brain was at one time just as tiny as an apes, and our size was smaller in stature, we had exaggerated brows, etc. Why have no other species been "selected" to be gifted with the ability to speak and reason?

Answer 1

Suppression. As a species advances it subverts the growth of other species and actively competes with the pre-selective trait version of itself. The successful branch then continues to supress other species from developing in order to maintain supremacy. It's all about survival and minimizing competition.

Answer 2

Evolution works best when a mutation allows the exploitation of some niche in the ecosystem which is currently unexploited. Evolution will always increase diversity so that creatures living in an environment where big teeth are a better survival technique than big brains will evolve even bigger teeth or evolve to a more effective form for exploiting that environment.
Intelligence has it's own limitations. We can build better weapons than those provided by nature, but only when we have reached maturity. As infants we are not predators but lunch.
An intelligent cockroach would not have better survival instincts than the current model. They do not need time to think because every reaction is hard wired. Stick 3 kilograms of brain in a cockroach and he needs to look for a new home and lifestyle.

Answer 3

An intelligent brain requires an enormous amount of energy to maintain. For not many species it must have been an advantage to develop this kind of brains to enhance their chance of survival as a species. Most likely it's been a combination of factors.
The fact that human ancestors became bipeds, gave them time to do things with their hands. The development of the more precise vocal chords that made sophisticated forms of vocal communication possible. These factors have probable been the initial factors in the stimulation of the human brain into intelligent brains. The fact that we learned to cook our food made that early humans were able to get the necessary amount nutrition, without spending almost all energy on the digestion process alone. This extra energy made it possible to sustain and further develop the human brain to what it is today.

Answer 4

A very good question. I would be interested in seeing all the answers. The other day there was a news story about a cat playing around with a computer. Just showing its curiosity. Animals have some ability to reason but their ability to speak must be done in a sign language type of way(except when speaking to each other). I hate to say this but some humans have only a small about of reasoning ability-I am speaking about those that are smart enough but not wise enough.

Answer 5

You're assuming that evolution only selects for intelligence and all other attributes are of no value. That's absurd. There are many different environmental niches, and in general there will be at least once species that is well adapted in that environmental niche.

Others have mentioned the competitive pressure. That factor explains why we are the only intelligent species. But humans can't possibly fill all of the other environmental niches, which explains why there is still such a diversity of life.

Answer 6

Because they don't need to be.

Don't think of life and evolution as a ladder trying to "achieve" consciousness and mammailian/human features.

Rather, each species is just trying to preproduce. We would not do very well underground, but moles do just fine with almost no sight.

Those moles don't sit around asking why humans never got rid of their eyes, developed paddles for arms and started digging underground, and nor should we request the opposite of them. They are good at what they are good at and we are good at what we are good at.

Now, humans are adept at living in a variety of environs because our our brains and our ability to adapt our environment to meet our needs. Obviously, the first species, regardless of which it is, to develop this ability will be the first to inhabit the entire earth and really makes its mark. That only makes sense given teh slow timelines associated with evolution. The odds of two species acquiring such traits at roughly the same time are pretty darn slim.

Though not impossible. Neanderthals, a seperate species, perhaps could speek and had pretty advanced cultures....and they lived contemporaneously with us. Unforunately, it appears our ancestors squeezed them out a few thousands years ago.

Answer 7

It depends on how you define "god". To many believers, God wouldn't be phased by a black hole (remember, he is supposed to be all-powerful, meaning escaping a pathetic little black hole should be no problem). As for immortality, I'm convince that, if we were to achieve it, it would be through no small contribution from technology rather than simply evolution. I'm not convinced that immortality is all its cracked up to be, though.

Answer 8

Parrots can speak and reason to a degree. So I dispute your premise, but intelligence is very very expensive. Much of our energy goes to support our oversized brain. Also It requires a very difficult pregnancy, a long childhood etc. none of which come easy.

Also we likely killed off our direct competitors. When two species share the exact same biological niche usually one or the other tends to prevail.

Answer 9

well if you the follow the model of evolution then eventually "all" will be intelligent beings. that's why evolution needs the earth to be millions and millions of years old because otherwise their "theory" would be shown to be more moronic than it already is. so i figure that the evolutionist will say something like "give it another billion years and everyone will be." but i ask will they all be human or will they just be intelligent lions, tigers and bears??? evolution is so silly a child could laugh it off as dumb.

Answer 10

Who does this "selecting", your talking about? God?
Energy finds it's path of least resistance to expand, through the constantly changing forms which we call "life". We can only see a quick snap shot of the whole picture from where we stand.

Answer 11

Maintaining a brain as large as ours takes enormous energy. If the other species are well enough suited to their environment, their genetics will not favor spending the energy on something they don't need.