re: Thumbs (Page 4/4)
ls3mach AUG 20, 08:44 PM
Apologies Chris. I was being fussy. Good luck all. Don and Ron I will send you both a PM soon I'm hoping you can answer a question with your life experiences. I'll be resetting life for a while.

Again Chris I'm sorry. This had nothing to do with you at all.

[This message has been edited by ls3mach (edited 08-22-2021).]

TheDigitalAlchemist AUG 23, 01:35 AM
Not sure what you are referring to, everything’s cool…u less you are the person who decided to close the Canadian border ANOTHER month… by the time I get that formula, it’s gonna be white…with SNOW!
Australian AUG 23, 04:43 AM

quote
Originally posted by williegoat:

Anonymously down-rating something is a tool for cowards. It is childish, like keying someone's car. It accomplishes nothing.



I have never owned a car that hasn't been keyed or vandalized. I did up my fiero after it was keyed and walked over. Happened again about 6 months ago to my Lexus. Some people just don't like being overtaken and are gutless wonders.

[This message has been edited by Australian (edited 08-23-2021).]

rinselberg AUG 23, 01:07 PM
There could be more to Thumbs than many of us have ever realized.

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The earliest tetrapods [four-limbed animals with backbones] had hands and feet with up to eight digits but this number was subsequently reduced during evolution. It was assumed that lineages with more than five digits no longer exist but investigations of clawed-frogs now indicate that they posses a rudimentary or atavistic sixth digit in their hindlimb. A recent reevaluation of the stem tetrapod Ichthyostega predicts that its seven digits evolved from two different types of ancestral fin radials, pre-axial and post-axial. In this context we now ask the question, should we consider a pre-axial origin of the thumb as reason for its unique genetic signature?


Earliest tetrapods, as in 400 million years ago.

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When the first tetrapods emerged from the water around 400 million years ago [1] their hands and feet looked quite different from the ones seen in modern day species. Instead of the five fingers and toes characteristic for ourselves and most other extant tetrapods, the hands and feet of stem tetrapods such as Ichthyostega and Acanthostega numbered up to seven or eight digits [2, 3]. For millions of years to follow, tetrapods had six digits until this changed to the canonical pentadactyl Bauplan at the end of the Devonian around 350 MYA [3–5] (a period whose tetrapods remain poorly known due to fragmentation of the fossil record [6]). This organization into a limb with five digits has proven extremely stable. Reductions are quite common (as in horses, pigs and birds) but supernumerary digits, beyond the “5”, are exceedingly rare and are only known from mutant or highly inbred domesticated animals [7].


Just the first two paragraphs of an article that was published in 2015. Includes a single diagram.

"The phantoms of a high-seven - or - why do our thumbs stick out?"
Joost M. Woltering and Axel Meyer for Frontiers in Zoology; September 15, 2015.
https://www.ncbi.nlm.nih.go...articles/PMC4570229/

I am not a scientist..!

[This message has been edited by rinselberg (edited 08-23-2021).]