the liver and the brain

r norman rsn_ at _comcast.net
Sun Sep 5 08:22:02 EST 2004


On 4 Sep 2004 20:53:45 -0700, feedbackdroids at yahoo.com (dan michaels)
wrote:

>r norman <rsn_ at _comcast.net> wrote in message news:<is5kj05apke4p3fhld15opsvt328tfkuag at 4ax.com>...
>> On Sat, 04 Sep 2004 18:20:33 GMT, lesterDELzick at worldnet.att.net
>> (Lester Zick) wrote:
>> 
>> >On 4 Sep 2004 09:35:30 -0700, feedbackdroids at yahoo.com (dan michaels)
>> >in comp.ai.philosophy wrote:
>> 
>> <snip>
>> 
>> >> ...  my question regards the level of development of
>> >>perceptual systems at the time of birth in precocial ungulates ...
>> >>
>>  
>> >>It's a fairly interesting problem in its own right, since a baby zebra
>> >>has to be ready to flee from a lion shortly after birth, if it ever
>> >>wants to get to be an adult zebra. To flee from a lion, it might help
>> >>to be able to distinquish one from a parent zebra, so upon seeing its
>> >>own parent, it doesn't go running off into the jaws of the nearest
>> >>lion. I guess it's conceivable the adult zebra would be able to
>> >>"teach" its baby what a lion is in the first hour or so, or that the
>> >>baby learns on its own the first time a lion comes to eat it. Operant
>> >>conditioning rules, so long as the organism makes it through the first
>> >>day against something 10X its size and power, not to mention the big
>> >>teeth.
>> >
>> >The baby zebra wouldn't have to learn to discriminate lions. It would
>> >just have to learn to stay with its mother, a much easier task for
>> >which it is presumably born pretty much ready.
>> >
>> >Regards - Lester
>> 
>> You are right in questioning the specific behavioral capabilities
>> needed for a newborn to survive.  Still, putting aside the particular
>> focus on ungulates and on recognition of predators as a specific
>> animals and behaviors there are still very interesting scientific
>> questions behind all this.  Exactly what are the differences in brain
>> development and function between precocial and altricial animals?  To
>> what extent does a reliance on learning vs. instinct play a role in
>> the behavioral repertoire of precocial vs.altricial animals?  
>> 
>> I would only just repeat here something I have been trying to say for
>> some time now.  These differences are well known and well recognized
>> as reproductive strategies with important implications for ecology,
>> evolution, ethology, and development. There is a rather extensive
>> literature about these, although not specifically about the ability of
>> ungulates to recognize predators.
>
>
>Yes, yes, to hell with ungulates. If you look at the *most* precocial
>birds on patty's found list, can you postulate the hypothetical
>balance between genetic hardcoding and post-natal development/learning
>regards their visual systems? I see ducks are near the top of the
>precocial list. Do they really "imprint" on their parents?
>
>http://www.stanfordalumni.org/birdsite/text/essays/Precocial_and_Altricial.html
>
>TYPE OF DEVELOPMENT DOWN PRESENT? EYES OPEN? MOBILE?. FEED.SELVES?
>PARENTS ABSENT? EXAMPLES
>Precocial 1 Yes Yes Yes Yes Yes Megapodes 
>Precocial 2 Yes Yes Yes Yes* No Ducks, Plovers 
>Precocial 3 Yes Yes Yes Yes No Quail, Turkey 
>Precocial 4 Yes Yes Yes Yes/No No Grebes, Rails 
>Semi-precocial Yes Yes Yes/No No No Gulls, Terns 
>Semi-altricial 1 Yes Yes No No No Herons, Hawks 
>Semi-altricial 2 Yes No No No No Owls 
>Altricial No No No No No Passerines 
>...

Many posts ago, I did refer you to the Megapodes, including the
partridges, pheasants, and quail.  These are fully independent at
birth and therefore at hatching have well developed sensory, motor,
and integrative centers that clearly are genetically determined.  That
ducks are highly precocial does not mean that learning, as in
imprinting, is not important in their early life.  It simply means
that there is a genetically determined system that requires a learned
component to be implemented fully.  I thought the whole trend in this
discussion is that there is no absolute distinction that can be made
between learning/environment/nurture and instinct/genetic
determinism/nature.  In many cases, probably in virtually all cases
for mammals and primates, they interact.








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