[FRIAM] Friday Fodder

[Prof David West]

Because I left before it ended, I have no idea how the spandrel discussion ended. Nick requested an explanation/elaboration/justification for my continued skepticism/resistance (other than being willfully obstinate for no reason) to the notion of spandrel. Hence the following — elaborated beyond the specific question of spandrel  as fodder for continuing discussion next Friday.

1- I am convinced that evolutionary biologists are secretly required to read Rudyard Kipling as prerequisite to the granting of a Ph.D.. Because, every story about the evolution of a specific feature — Friday it was the pseudo-penis of female hyenas — sounds like, and is as convincing as, one of Kipling's *Just So *stories. *[Yes, trolling.]*

2- Pseudo-penis as spandrel:
   a- Testosterone flooded female hyenas are selected because aggressive females have survival value in matriarchal hyena society. This really seems, to me, to pose a chicken-egg problem: matriarchy or female bullies first?
   b- Testosterone flooding creates a space — a spandrel — a space that is then "decorated." One example of 'decoration' is the pseudo-penis.
   c- by what mechanism does the decoration come about? Nick said it was a direct result of testosterone flooding, that "all" such results would appear, that none of them was independently 'selected for." This is a specific area where I fail to understand what Nick is saying and need correction. If I heard correctly that all effects of testosterone flooding would appear — Nick emphatically said "all" and "will" in his explanation — then:
    -- we should not only see a clitoris run amok, but also beards, rock hard pecs instead of pillow-breasts,  20-inch biceps, denser bones, and overall greater muscle mass.
    -- the "purpose" of the pseudo-penis is aggression display and reproductive-act dominance. But, of all the results of testosterone flooding that "will" result, a big penis seems the least useful for that purpose. Muscles and size would seem more than sufficient. Consider Arnold in the role of Terminator. He managed to convey a lot of menace and dominance simply from size and overall shape; never once brandishing his penis to intimidate anyone. (And if we assume he was as liberal a user of steroids in his body-building career as many of his colleagues, his penis would not have scared a squirrel.)
    -- Why so baroque a decoration?
    -- Why did testosterone cause the clitoris to merge with the urethra and the vagina? Did these not exist as separate organs in predecessor species to the hyena? How is that even possible? is the pseudo-penis not a clitoris-urethra-vagina at all but some kind of evolution of an avian cloaca?
    -- This specific decoration seems to have anti-survival consequences (most firstborn hyenas are also stillborn) and yet this decoration seems immune to selection. Or maybe not, we have yet to see what might succeed hyenas a few million years from now.

3- More general issue: whole-part evolution. Jon seemed to understand what I was trying to say last Friday on this matter.
   a- Consider the peregrine falcon. Some of the traits/features that make it a formidable predator: very lightweight bones coupled with overdeveloped muscles which contribute to its ability to withstand G forces and make 200 mile per hour dives (and withstand the shock of kinetic energy when it hits its prey); razor sharp talons; notched beak to sever spinal columns; full-color binocular vision with resolution that allows seeing a pigeon at distances greater than a mile; nictating membrane to protect from wind force during dives; and ability to see into the ultra-violet spectrum.
   b- If I understand Darwin *(a huge if):* each of these features is the result of a sequence of selected/preserved minute changes in single molecules: e.g. keratin, opsins, crystallins. Each of these molecules are expressed as a sequence of amino acid 'letters', 20 in number. If the string of letters were 100 characters in length (crystallins and opsins are much longer) then the odds of any given string are 20 to the 100 power. By comparison, the number of hydrogen atoms in the universe is estimated to be 10 to the 90th power.
   c- If evolution proceeded with one amino acid letter pairing with a second, getting selected, then pairing with a third, etc., each addition being one of 20 equally probable options; then, coming up with the string that expresses, precisely, as the falcon's beak is fantastically improbable (winning the lottery every year since the Big Bang).
   d- This brings in the question of time. Has there been sufficient time for a process of random change / selection to allow the formation of such a string. This was a huge issue for Darwin because the prevailing scientific estimate of the age of the Earth was twenty-million years. [Lord Kelvin using the equations of thermodynamics.] This was not nearly enough time for Darwin's evolution and he was **"greatly troubled by it."** Rutherford, using radioactive decay equations, *"saved"* Darwin by extending the age of the Earth to 4.5 billion years.
   e- **Kind-of**. If evolution literally proceeds one amino acid letter at a time to assemble a specific string that has a probability of existing of 1 / 20 to the hundredth power (or more) — there is insufficient time since the Big Bang for that string to emerge via chance.
   f- it seems as if some kind of short-cut is essential. Suppose you have parallel/simultaneous evolution of 'sub-strings' and then 'main-line' evolution proceeds upon combinations (wholes) of these strings, Then, it is quite likely that 4.5 billion years provides sufficient time. This, it seems to me, suggests that evolution deals with an aggregate, a whole; not individual amino acids one-by-one, or even sub-strings one-by-one.
   g- Which circles back to the falcon. If each of the mentioned traits/features evolved independently and sequentially then we run out of time again. If each of the traits/features evolved independently then there seems to be a macro-problem of how they 'just happened' to occur simultaneously and apparently 'in concert'.

So my conclusion, *apparently wrong because it disagrees with the experts in the group*, is that evolution must proceed whole-organism to whole-organism and not, feature-trait by feature-trait the way that it is presented.

This also means, that individual feature-traits — as marvelous as the the falcon's eye or as silly as the pseudo-penis — cannot, and should not be "explained" independently. To do so is to focus on the 'noise' and not the 'signal'. Such efforts are the product of 19th century thinking and unworthy of complexity scientists like yourselves.

davew
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