Evolution: complexify or not (Evolution)

by David Turell , Saturday, January 18, 2020, 20:15 (1560 days ago) @ David Turell

It is interesting that some animals appear and do not change to any real degree and others make enormous changes. Scorpions show very little change from the earliest ones found:

https://www.smithsonianmag.com/science-nature/worlds-oldest-scorpions-437-million-year-...

"...new research is pushing the scorpion timeline further back than ever before and may help pinpoint the traits that helped these pint-sized predators make a living on land. Today in Scientific Reports, paleontologists announce the discovery of the oldest known scorpions to date: a pristinely preserved pair of 437-million-year-old fossils, complete with what seem to be venom-packed tails.

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"Together with other, younger fossils from the same geologic period, the ancient arachnids suggest that scorpions have looked and acted in much the same way ever since they first appeared on Earth.

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"Early scorpions could blur the line between sea- and land-dwellers. Something had to crawl out of the water first, perhaps adopting an amphibian-like lifestyle. Parioscorpio’s physique, a mashup of marine and terrestrial traits, hints it was a good candidate for this double life.

"The heads of more recent scorpion species are adorned with multiple rows of beady, pinprick eyes. But Parioscorpio saw the world through bulbous, front-facing compound eyes, similar to the ones still found on today’s insects and crustaceans, as well as its ocean-based ancestors.

"Most of Parioscorpio’s other body parts, however, looked more contemporary. Like the scorpions that plague us today, this ancient animal boasted clawed pincers and a tail that likely tapered into a venomous stinger (though the actual tip, if it existed, has been lost to time). Even its insides were a match: The fossils were so exquisitely entombed that Wendruff could still see the delicate outlines of a simple tube-like gut and a series of hourglass-shaped structures that might have housed their hearts—all of which resembled the innards of modern land-dwelling scorpions.

“'The amazing preservation of the internal anatomy … reiterates how the [scorpion] ground plan has stayed the same, not just on the outside, but the inside, too,” says Lorenzo Prendini, a scorpion evolution expert at the American Museum of Natural History who helped uncover another batch of Silurian fossils from this lineage, but wasn’t involved in the new study. “It’s an ‘if it ain’t broke, don’t fix it’ mentality.'”

Comment: There are many sorts of examples of change or no change: it seems scorpions never evolved much from their start. Mammals jumped into the water and became whales. Humans quickly evolved from apes. We can look for circumstances that pushed the changes but the reason we find as guesses and at times the changes are unreasonable. Mammal did not need to enter the water, as most mammals have survived just as they are. Apes have remained just fine over eight million years. Human appearance was not required. Which raises the observation that evolution could be following a drive by a designer.