this post was submitted on 08 Nov 2023
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I actually fact checked this and it's true.

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[–] miss_brainfart@lemmy.ml 52 points 1 year ago (1 children)

And then you add the fact that sharks have barely evolved because they've been the perfect silent killer since the dawn of time.

Another fun fact:
Sharks don't make sound. They don't have any organ for the purpose of making sound. That is creepy as all hell.

[–] Gladaed@feddit.de 13 points 1 year ago (2 children)

Just because they didn't change their appearance doesnt mean they did not evolve. It is somewhat misleading to say that, but conveys a point I guess.

[–] miss_brainfart@lemmy.ml 6 points 1 year ago

I made sure to say barely instead of not at all, but you're right, there was certainly some evolution happening

More relevantly, the fossil records for sharks are mostly their teeth and jaws, because all their other bones are cartilage and rarely fossilize.

"Sharks haven't significantly evolved in appearance in 350 million years" is therefore based on reconstructions made under the assumption that the old sharks mostly looked like current sharks, which may or may not be true.

Though we can get a surprising amount of information that way, for example one change is that their jaws used be more at the end of their snout instead of more underslung like today, like so:

https://www.smithsonianmag.com/science-nature/new-technologies-reveal-strange-jaws-prehistoric-sharks-180977396

You'll note the Goblin Shark still has hints of that design.

[–] oshitwaddup@lemmy.antemeridiem.xyz 49 points 1 year ago (1 children)
[–] hallettj 38 points 1 year ago

Wow, this is one of the most complicated Snopes analyses I've seen. But it seems like the statement is accurate with caveats. If the brightest component of Polaris is probably 50 million years old what was there before wasn't really Polaris. And then it doesn't make a difference whether sharks have been around for 450 million or 195 million years.

[–] DrinkMonkey@lemmy.ca 21 points 1 year ago (1 children)

It is partly true. Polaris is in fact a triple star system. The youngest of the three stars (Polaris Aa) is indeed younger than sharks at between 45 and 67My old. It is in tight orbit with Polaris Ab which is 500My old, and Polaris B which is 1.5By old and a little bit farther away. Here’s a pic from Hubble:

https://en.m.wikipedia.org/wiki/File:Polaris_alpha_ursae_minoris.jpg

[–] Track_Shovel@slrpnk.net 16 points 1 year ago (2 children)

I feel cheated that the north star is in fact 3 stars.

[–] DrinkMonkey@lemmy.ca 8 points 1 year ago (1 children)

Me too. It’s a sick fact. Sharks are still older than trees tho…

[–] DrinkMonkey@lemmy.ca 6 points 1 year ago

I think it’s also worth mentioning that Polaris Aa, the youngest star in the triplet, is also the brightest by 3 orders of magnitude. Without Polaris Aa, we wouldn’t actually consider it as the North Star at all…so I think you are safe to continue using this as a fact.

Go blow some people’s minds, everyone!