Re: I still don't understand the tears...
ROBERT SAUNDERS (rdcsaunders@its.dundee.ac.uk)
Fri, 20 Oct 1995 12:37:31 GMT
In article <465lbt$kbe@scotsman.ed.ac.uk> jamesb@hgu.mrc.ac.uk writes:
>If beavers don't shed emotional tears then this means that only elephants
>and humans and many marine animals shed emotional tears. So this makes it
>more plausible to suggest marine ancestors for humans and elephants.
No it does not. I see no requirement that the evolution of emotional tears
requires marine ancestry. At all. Given that most animals ahve tears to
maintain eye moisture, then it is relatively trivial for evolution to recruit
tear fomation for other purposes, such as displaying emotion. There is
absolutely no necessity to invoke any mysterious function such as salt
excretion.
>>In fact, you could even argue that to go from isotonic tears for eye
>>protection to isotonic tears as an emotional display is more parsimonious
>>(and, according to some peoples thinking more probable) than to go from
>>hypertonic excretory tears to isotonic emotional ones.
>>
Yes!
>To support this argument you would have to give me an example of a purely
>terrestrial animal (Obviously besides humans) that has gone from isotonic
>tears for eye protection to isotonic tears as an emotional display (Prove
>that elephants don't have a marine ancestor and AAT is stuffed). It is a
>testable hypothesis of AAT that there aren't any. I have given references
>that confirm that some animals that have hypertonic excretory tears also
>shed these tears when emotionally upset. My hypothesis (can you think of
>a way to test it?) is that our ancestor's tears were hypertonic.
Prove that humans didn't go directly from isotonic eye protection tears to
isotonic emotional tears!
>To conclude : only marine animals, elephants and humans shed
tears when >emotionally upset. Why?
>James Borrett.
James, do you understand evolution?
Robert Saunders
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