Why aren't all animals becoming smarter?

From what I have understood, the "intelligence" of humans has happened because it came under both natural and sexual selection - directionally - for increased intelligence. Intelligence, from an anatomy standpoint, being the increase in density and proportion of the frontal lobe.

More to the point - until scientists can agree on what constitutes intelligence - than you cannot answer the question. Many birds, fish, small mammals, etc. exhibit quite a bit of "intelligence." (If you saw a two-year old human doing the same activities you would be startled at the level of understanding. There are adults that cannot build the convoluted nests of some birds with or without tools.)

So, what is intelligence? Is it intelligent, for example, for a dog to know when to back down to a stronger alpha male? If the use of tools is intelligence - that is done in many other animals. Same for problem solving. Is the presence of language intelligence? Many other animals have some form (verbal or non-verbal) of communication that could be called language by definition. Is it intelligent to have some sort of social order? Again, present in many animals. Is self-awareness intelligence? Can you measure that awareness and determine if it is not in other animals?

Who are we to say that we know all of the subtleties that go in to any one action.

As for complexity of any of the above traits - the scientist who thinks that they have observed all there is to know about a phenomenon is neither wise nor very good at their job.

Sorry....off the soap box.

 

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Makes you wonder.

How can an organism that survived as a collection of simple unicells with only minor adaptations for two billion years, can suddenly reinvent itself and diversify into multiple forms with previously unnecessary means of competion, locomotion, and internal organs?


I wonder how much about evolution we really understand.

 

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not eveything, I am sure, but we are certain that no organism did what you are asking about (in your text I made bold). That develpment was very slow to reach the items the second bold part of your text lists.

 

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Thanks for your objection Billy.

My understanding is that evolution was for a huge amount of time without much change, and then went through a period of comparitively rapid change.

Would be grateful for any facts regarding evolution's timeline as regards complexity from yourself, or others.
I'm quite happy to be mistaken, if I am, as this Sudden leap does not make sense to me.

 

Here is a timeline.
The precambrian section at the far left, if it was to scale, would take up three quarters of the timeline.

http://www.amonline.net.au/spiders/images/diversity/evolution_timeline.gif

 

Brain size in hominids has increased from about 400ml to about 1400ml
over the past 3 to 4 million years.
http://www.massey.ac.nz/~alock/hbook/brain.htm


The current theory on why humans became more intelligent
was that it helped them to adapt to seasonal weather as they moved further north,
but why just humans?

http://www.theregister.co.uk/2007/03/26/research_skulls/

 

The current theories include that one as a dubious possibility.

More likely (in standard estimations of this kind of event) the intelligence increase is what allowed them to move out of their adapted niche (which was changing), and the sudden availability of multiple niches (south, east, and west, as well as north) put a premium on an intelligence already well established, from then on.

The payoff for increased intelligence got very large very fast, for all humans, when the weather changed again and the first intelligent wanderers left Africa - but that payoff probably (almost certainly) depended on the intelligence being largely present, already, for other reasons.

Why just humans? Maybe because only they could. They already had the basics - the physiological and developmental ground for boosted brain size, the tool use, probably fire, the upright posture allowing the carry bag (my vote for the single most important human invention), the social setup, the omnivorous diet and metabolic adaptation to patchy rich food from complex environments (preventing a superior payoff to physiological specialization on a food source), and so forth.

They were in a rare situation, and opportunity knocked. Kind of like rats or pigs landing on Tahiti, only with hammer stones and carry bags instead of gnawing teeth and rooting snouts.