we are walking fish

Richard Stewart cuatle at cats.ucsc
Thu Oct 31 11:50:58 EST 1996

In article <555uvf$89j at dfw-ixnews12.ix.netcom.com>, olskool at ix.netcom.com
(Tony) wrote:

> ///Adam Hibbert writes...///
> >For this to be true, you must in some sense be suggesting that, 
> whatever
> >medium we evolved in, we would 'find' a way to 'see' through it
> >(presumably permitting that we 'see' in whatever radiated/convected 
> datums
> >we can). So, for example, soil is 'transparent' to moles through their
> >incredible sense of smell. But how come dolphins can 'see' (with 
> sonar)
> >through me? Because they evolved in me? Help me out with that one.
> Adam:
> You are jumping from the general (that dolphins have sonar and can see 
> "through" solid objects) to the particular (that since they can see 
> "through" a very specific particular object, a person, they evolved 
> within that person.)   This is a non sequitur!
> Moreover, I am not even sure that sonar allows dolphins to effectively 
> see "through" solid objects.   First, when it comes to using sonar to 
> see "through" the flesh of a living organism, we must remember that 
> sonar is sound waves and sound waves are propagated through matter.   
> Every compound has a specific density which affects the velocity of 
> sound waves propagated through it.   Since humans are two-thirds water 
> by weight, our specific density would be close to that of water.   The 
> speed of sound through humans would be close to the speed of sound 
> through water, although it would probably be slower since the non-water
> elements which compose us in part would affect the average, and some of
> these substances, like bone, are much denser than water.   However, all
> in all, the specific density of a human being would be not much 
> different from that of a FISH (fish have bones), though MORE different 
> from that of a shark (sharks have no bone, only cartilage, which has 
> more water in it).   A dolphin could be expected to "see" an object on 
> the far side of a human AS LONG AS it has a DIFFERENT specific density 
> than the human.   A dolphin wouldn't "see" a fish on the far side of a 
> human, because it's sonar detectors (ears) couldn't tell the difference
> between sound waves reflected from the fish and from the human, since 
> both are very similar in composition and density.   However, a dolphin 
> COULD "see" a brick wall on the other side of a human (hell, it could 
> see THAT one coming with its eyes!); a dolphin COULD see a rock (even a
> small one) on the other side of a human, but its brain might not be 
> able to tell whether the rock is part of the human or in the human, or 
> on the other side.   That would require help from the part of the 
> dolphin's brain that interprets and correlates visual and auditory 
> stimuli; maybe that is why dolphins have such huge brains and are so 
> intelligent!
> Tony

Based on the above logic, before we philosophical venture into the realm
of circular arguement, we must remember that all evolutionary adaptations
occur in accordance to ontological constraints and developmental
processes.  To generally state that humans are walking fish would be like
claiming that all stars evolved from our sun (respectfully acknowledging
that the evolution of astrological systems differs from the evolution of
biological systems) or for a better analogy, that all humans are walking
plants because of the uncanny similarity between the structures of
chlorophyll and hemoglobin molecules - both used in transport. 
Evolutionary theory, no doubt, proves that all living things on this
planet are related and have evolved in conjuction with conspecifics within
a an organisms given niche.
A good exercise to strech a few neurons, but hardly a valid hypothesis. 
Try toying around with aquatic ape theories if you really want to work
from a better frame of reference.

Take care.


More information about the Mol-evol mailing list

Send comments to us at biosci-help [At] net.bio.net