An Alternate Human

B0b Barker writes "What has six limbs, a prehensile tail, its brain in its chest, and reproductive organs in its mouth? The alternate human designed by biologist PZ Myers in Remaking Humanity, a story in Forbes.com's package on Reinvention. It may sound fantastic, but researchers are already working to re-build DNA, proteins and cells in a new field called synthetic biology, and we may have to meet these bug-eyed freaks sometime in our lifetime."

The problem of nerve impulse conduction

[TripMaster Monkey]

From TFA:

There's no particular necessity that the brain would form in the head--that's again a product of convenience, since more sensory organs were located in the front of the animal, and induced an enlargement of the local part of the nervous system to cope with their input.

So let's meddle again, and instead put the brain somewhere near the middle of the animal. In that position, it can be better protected by the mass of bone and muscle in the chest, and also be more conveniently located relative to the heart and circulatory system. It changes our head from a bulbous housing for a crucial, delicate organ, all poised on a fragile stalk of a neck, to a flexible sensory and feeding apparatus.

In addition to convenience, there's a good reason the brain is located in the head...in close proximity to the major sensory organs (eyes, ears, nose, mouth). This placement minimizes the time lag of neural impulse conduction, by minimizing the necessary length of nerve connecting the sensory organs to the brain. For this reason, I wouldn't expect many species to evolve with a larger-than-necessary distance between their brain and their sensory organs (unless such creature evolved a much faster method of conducting nerve impulses than we possess).

Re:The problem of nerve impulse conduction

[ceoyoyo]

Some of your reflexes are controlled from your spine as well. Very much faster than waiting for nerve impulses to travel up to your brain and back.

Careful what you wish for!

[StefanJ]

Fur is high maintenance. It gets all over, has to be brushed a lot, harbors parasites, and makes it hard to keep cool.

My dog has a brutal time in summer:

http://home.comcast.net/~stefan_jones/kira_grinnin g_lo.JPG [comcast.net]

Some dog owners just give their pups a full body trim in late spring.

The molluscs shall inherit the Earth.

[gobbo]

It seems that the central-brained creature in TFA would, in most practical terms, resemble a mollusk. However, on this planet, invertebrates aren't the creatures that developed sentience...

You could be right, but we don't know for sure. It depends on how one defines sentience, and what we discover as we explore the oceans, as we're just beginning to do.

The case could be made that the mollusc body plan is the most successful on the planet. Squid, for instance, out-mass pretty much all other animals, in an astonishing variety of ecological niches (okay, not sure about krill... any biologists care to refresh my memory?). Molluscs can be found in just about any part of the earth.

As far as sentience goes, if humans crap out and extinct ourselves, my vote for the next evolutionary chance at the reign of intelligence would be for the cephalopods. They're adaptable, have a proven problem-solving intelligence, are highly communicative in ways we're just beginning to understand, have excellent eyesight, and octopuses in particular are highly dextrous.

Don't underestimate the mighty mollusc.

Re:reprod organs in mouth?

[Rude Turnip]

For one thing, your video store would have to move Urotsukidoji from the anime section to the nature film section.

Re:The problem of nerve impulse conduction

[AviLazar]

The brain needs to maintain a certain balance. Too cold and it shuts-down (killing you)...too hot and it "melts-down" killing you. On a processor - too hot and it "melts-down" too cold, well now you can overclock it through the nose :D

The brain needs to maintain at a certain temperature...that is one of the reasons when people have fevers they put cold towels on their forehead. On occasion, if a person is REALLY under a strong fever (or say on too much ecstacy) they will submerse the person in ice to cool the body down so it does not over-heat the brain.

Re:The problem of nerve impulse conduction

[Suidae]

The few children born without pain receptors generally survive, but by the time they are adults they look pretty rough, missing eyes, covered in scars, etc. Teething babies with no pain receptors tend to happily chew the skin off of their fingers. When they break bones they only complain if the protruding bone ends get in the way.

Now, if we as adults could easily learn to limit pain pereception to the level of "persistant, attention-drawing annoyance", that would be useful.