[Brian Saunders]

Brian Saunders asked the Naked Scientists:

Chris
As I understand it, the dinosaurs inhabited the Earth for circa 200 million years. Is there any theory on why they did not develop similar/better  intelligence to ourselves given that they were around a lot longer that Humans? Presumably over that extended period of time the circumstances which resulted in our developing further would surely have been duplicated at some stage.

Also, given the extended time period between their demise and our emergence would any evidence of intelligence/technology have possibly survived?? If Humans were to suddenly become extinct what is the estimated time frame before all trace of our existence would be lost?
 
Love the show. Thanks
Brian

What do you think?

[Simon Waters]

Not my discipline, but some of the popular science books on evolution have put the boot into "intelligence" as a survival strategy (compared to say sharp teeth, or bigger ears).

Hominids spent hundreds of thousands of years making roughly identical stone axes in Africa (something which would probably survive if the dinosaurs had done the same extensively). It in only in the last 25,000 years we've shown much initiative as far as technology goes.

If it were simply environmental conditions this led us to develop technologies, why did it only affect one species of hominid? Why not other species exposed to the same conditions?

The simplistic argument is that intelligence isn't a good survival strategy. Knowing it will get cold, and that you need to put food down for the winter may seem obviously good, but is it better than doing it out of instinct like a Squirrel (squirrels may be good at remembering where they bury food, but they are useless at remembering which food they have eaten already as the holes in my lawn show), or bears?

I suspect the real answer is more complex, and it is possible that some technologies have been developed in the past and completely lost. Similarly other aspects limit evolution of intelligence. Human (birth) brain size it is argued is limited by a woman's pelvis, which thus mandates a long period of helpless infancy, whilst our parents nourish us till our heads grow. It may simply be that reptile body limits the intelligence that can be supported in some way, so there was no route from dinosaur to digital watch. It may be large highly evolved predators prevented other species acquiring the necessary adaptions.

Basic intelligence is pretty wide spread in the animal kingdom, primates, cephalopods, cetaceans all have members who are pretty clever. I suspect it isn't simply intelligence that distinguishes humans. It also isn't simply the opposable thumb, or language. I suspect technology is a result of a combination of these things, leading to rich cultures, in the kind of messy twisted story only evolutionary systems create.

[Bored chemist]

Brains take a lot of energy to run them. For a lot of animals that energy is better spent making babies.
If you are the size of a big dinosaur then you don't need to out-think your oponents very often.

[RD]

Some claim that modern birds are descended from dinosaurs.

Allegedly some birds are as intelligent as a pre-school child ... http://www.abc.net.au/news/newsitems/200607/s1693309.htm

[Don_1]

It has been suggested that they were not the dim witted creatures we once believed them to be. Dinosaurs probably achieved the limit of knowledge necessary for their individual species. I see evidence of this in my tortoises, after nearly 300m years of evolution, they are still the same as they were in the Jurassic period. They have no need of further brain power. There would be no point in a tortoise having the ability to learn how to drive a car, since the body has not evolved in a way to make it physically possible.

Evolutionary brain power and physical adaption go hand in hand.

[DoctorBeaver]

There is a theory that it has to do with cooked meat. Cooked meat is easier to digest so more nourishment can be absorbed per unit of energy used for digestion. Once early man began cooking meat, less enrgy was used for digestion and more could be diverted to the brain which grew as a consequence.