We’re watching evolution happen in real time with Covid19. It’s a fascinating horror show best experienced in New Zealand.
A recent article described what’s happening with the various strains of covid as convergent evolution. There are better examples to demonstrate this concept.
Did you know that a bunch of aquatic species are evolving into crabs?
Today’s Moment of Science… I, for one, accept my Crab People Overlords.
There are a few concepts in evolutionary biology that people far too often use interchangeably. Evolution. Natural selection. Survival of the fittest.
I see douchewhistles throwing these phrases around with the same level of confidence they invoke when talking about bitcoin and they’re equally wrong about both. So let’s clear up a few things.
Uh, about evolution and associated terms. I know fuckall about bitcoin.
Species generally have some degree of genetic variation and competition for resources to survive. In species that reproduce sexually, organisms with traits that are better adapted for their environment are more likely to survive to pass their genes on. This is known as natural selection; the person at the bar quietly licking their eyebrows is going to pull more than you, that’s just science. Evolution is essentially compounded natural selection, the results of genetic shifts that take place over a length of time that humans can’t wrap their head around. Generations upon generations of genetic changes eventually add up to a vestigial tail.
When we think of evolution, we’re generally thinking of divergent evolution. It’s when a common ancestor accumulates a series of genetic and physical changes that subsequently leads to a new species emerging. Imagine some sort of proto bird species scattering across the world millions of years ago. The only food in your area is dead carcasses? Birds with exceptionally strong stomachs and faces that look like satan’s nutsack survive that, and eventually vultures become the lovely monsters that they are. Chickens and peacocks come from the same family, so it seems they landed in vaguely different environments about thirty million years ago for each of them to thrive. And divergent evolution is likely why the airspeed of an African swallow is different than that of a European swallow.
Then there’s convergent evolution (not to be confused with parallel evolution, which we’ll get to another day). Take what we just talked about and throw it out the window. You take two entirely unrelated species and they…
Somehow…
Turn into the same goddamn thing.
I mean not genetically but they can pick up a lot of the same traits. This happens throughout the living world, but for just a minute, we gotta talk about the crabs. Because maybe carcinization’s a symptom of a new covid variant and I’m not taking any chances.
While you’ll get a one-off here or there of a species evolving traits in common with a distant relative, several species have crabified. Carcinized. Undergone carcinization. Whatever it is, it’s kinda weird.
King crabs, hermit crabs, porcelain crabs, and even those goddamn terrifying coconut crabs? Not fucking crabs.
And yet, highly crablike.
So what gives? Are the crab people real? Is this a side effect of the time I dumped anti-depressants down the toilet? Are crabs our final form?
Nah. The likeliest reason? Under similar sets of conditions, certain traits give you an evolutionary advantage. In this case, a body shaped like a crab seems to be an advantage on the ocean floor. Given millions of years, competition for resources, genetic drift, and if there is a god they have a whacked sense of humor, creatures just keep ostensibly turning into fucking crabs.
This has been your daily Moment of Science, and an apology to the evolutionary biologist reading this right now shaking their head saying “it’s more complicated than that.”
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