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Why do certain species stop evolving?
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It just works
They do keep evolving though
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>>10368668
It's pretty hard to evolve when your species is extinct.
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>>10368674
because they got civilization to take care of the weak, retarded and unfit
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>>10368668
no better way to get ahead
https://youtu.be/YT1vXXMsYak?t=28m25s
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>>10368675
But the horseshoe crap isn’t extinct
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>>10368683
was OP saying horseshoe crabs stopped evolving?
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>>10368668
perfect beings are immutable
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>>10368689
Op gave pic related as an example. Fossil records show the horseshoe has stayed the same since ancient to modern times.
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Some species or clades remain in a relatively static state over long timespans because they’ve reached an adaptation optimum, meaning changing in any significant way would DECREASE fitness.
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>>10368701
it has the same skeletal shape but that doesn't mean everything has remained the same about it
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If they stopped evolving then that must mean there's very little genetic mutation. Wouldn't that also mean they should be immune to cancer? I hear their blood is used in cancer research but I don't know any details of this research.
Is the anti-cancer properties in their blood what prevents them from evolving?
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their environment doesn't change
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>>10368987
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>>10368964
Nothing stops them from mutating. Natural selection stops divergences that cause significant change from propagating.
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>>10368668
evolution never stops for a species, you're mixing up the idea of not seeing phenotypic changes with no evolution. the body plan of an animal might stop changing because it's the best body plan for it at the moment, but even then there's probably small changes going on anyway within each population. this is kind of an expected result for a species that stays in a single niche for a long time that doesn't experience regular disturbance.
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>>10368964
their blood is used to check whether medical equipment is sterile, not for fighting cancer directly
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>>10368668
You need selection pressure for that.
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>>10368668
I believe some species gets trapped in a local maxima in terms of fitness; any significant improvement would require it to deviate significantly from its current design, and the path to that change will require several generations that are less fit that other of its kind.
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>>10368668
Lack of evolutionary pressure, or excellent fit into the environment.
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>>10368668
Because evolution isn't a thing. Duh.
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>>10369515
interesting hypothesis.
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>>10368668
Nothing stops evolving. A creature either dies out because it got eaten or died, lives in balance with what it eats and what eats it, or just keeps making more of itself, producing a wider variance of traits within the species until speciation occurs or catastrophe strikes and only a portion of the population survives.
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>>10369515
Is there literature out of this idea? I'd like to learn more about it.
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>>10368668
Because (((they))) are trying to hold back other species to limit their competition. . . Nature has a tendency to progress towards ever more elegant and complex structure, and this is especially true of biological life. If you see something that goes against this tendency you can be pretty confident that it has to do with Jewish meddling.

But anyway, try not to think too much about that. Just be a good goy and don't concern yourself with the horseshoe crabs.
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if it aint broke dont fix it
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>>10369515
ive always assumed this was already part of the idea of evolution
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>>10369515
This is exactly the argument used to say certain aspects of the human eye could not evolve. Each step forward would require two steps backwards first. The superior oblique muscle used to control lateral movements of the eye serves no purpose until it exists in its final form. Its a simple pully mechanism. The pully has no reason to exist unless the muscle exists first and if the muscle exists first a pully would merely offset the muscles direction off pull, making the muscle less efficient until the pully moves to an exact position where the muscle now forms an oblique direction of pull compared to its two anchor points. It magically "happened" though and this impossible conundrum is totally ignored.
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>>10368668
Because the horseshoe crab is the perfect organism. There are no improvements you can make upon it.
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>>10368668
They became the ultimate lifeform.
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>>10368668
>stop evolving
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>>10371978
Eyes without muscles for moving the eye do exist.
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>>10372215
Thats irrelevant. The point was that sometimes to get from one form to another the "evolutionary" process must have spend a very long time paradoxically making a species less fit to get that new novel feature. The alleged evolution, or total lack of a valid explanation thereof, of the superior oblique is an example of just that.

There is no species where an eye muscle trochlea (pully made from ligaments) is uselessly migrating towards a position where it will serve an actual purpose in 50 million years, all the while making the muscle going through it mechanically less efficient.
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>>10368947
this
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>>10372669
Nigga has eye muscles
Niggas son has two eye muscles
Niggasons son has second eye muscle move to the side
You dumb?
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>>10368999
Good, fuck ocean life. t. Chad Landdweller.
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>>10372669
>The point was that sometimes to get from one form to another the "evolutionary" process must have spend a very long time paradoxically making a species less fit to get that new novel feature.
Prove it. Doesn't just assert that it "must happen" in one way, demonstrate that no evolutionary uphill pathway exists.
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>>10368703
I can't find any other explanation than this
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>>10368668
this better not be another horseshoe hate thread
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>>10368964
Halt in evolution doesn't mean immunity to mutation. It's just that mutated units are worse than other ones and are less likely to mutate, making that mutation go extinct and leave species as they were before.
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>>10371111
Me too. It's so intuitional
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>>10368668
You got answers in this thread, but just to expand on the fitness equilibrium trap it's still possible for individuals or populations to continue evolving out of the original species like later homos from australopiticus, and then the original species either remains or it gets outcompeted or it succumbs to natural events.
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>>10369515
>>10368668
>>10374196
Actually it looks like this might not necessarily fully explain why.

http://www.mit.edu/~krugman/evolute.html

The answer is surely the ever-present need to simplify, to make models that are comprehensible. The fact is that maximization and equilibrium are astonishingly powerful ways to cut through what might otherwise be forbidding complexity - and evolutionary theorists have, entirely correctly, been willing to adopt the useful fiction that individuals are at their maxima and that the system is in equilibrium.

Let me give you an example. William Hamilton's wonderfully named paper "Geometry for the Selfish Herd" imagines a group of frogs sitting at the edge of a circular pond, from which a snake may emerge - and he supposes that the snake will grab and eat the nearest frog. Where will the frogs sit? To compress his argument, Hamilton points out that if there are two groups of frogs around the pool, each group has an equal chance of being targeted, and so does each frog within each group - which means that the chance of being eaten is less if you are a frog in the larger group. Thus if you are a frog trying to maximize your choice of survival, you will want to be part of the larger group; and the equilibrium must involve clumping of all the frogs as close together as possible.

Notice what is missing from this analysis. Hamilton does not talk about the evolutionary dynamics by which frogs might acquire a sit-with-the-other-frogs instinct; he does not take us through the intermediate steps along the evolutionary path in which frogs had not yet completely "realized" that they should stay with the herd. Why not? Because to do so would involve him in enormous complications that are basically irrelevant to his point, whereas - ahem - leapfrogging straight over these difficulties to look at the equilibrium in which all frogs maximize their chances given what the other frogs do is a very parsimonious, sharp-edged way of gaining insight.
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>>10368668
no evolutionary pressure
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>>10374071
>prove something does not exist
You need to prove it has a benifit existing in a half complete form(you cant, nobody ever has). And on top of that prove why a troclea would exist without a purpose as it only serves a purpose once its in the correct position which it would not be at its inception. The burden of proof is on you, not me as one cannot prove a negative... youve heard that before right?

Ive already explained how it has detrimental effects on muscle efficiency before itcreates a novel feature(thats easily proven with math). You have zero reason to think an evolutionary "uphill" path exists, you just believe one exists out of religious like faith. Take an introductory mechanics class to learn more.
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>>10374196
That isn't real, right?
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>>10368668
The model of their current phenotype is essentially the best for their current role in the environment and any improvement would be reliant on a mutation or come at some kind of loss.

Pic related
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>>10375384
what would it imply?
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>>10368668
stable dna, no selective pressures.
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>>10368668
You still don't understand what you're dealing with, do you? The perfect organism. Its structural perfection is matched only by its hostility.
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>>10368668
You can not improve perfection, Anon.
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>>10368668
Because they go extinct.

>>10368701
It isn't the same.
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>>10368703
>things don’t change because they don’t change
Sounds like a tautology.
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>>10374203
ok listen i get what you're saying but there's no way i trust paul fucking krugman on evolutionary biology
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>>10368676
>weak, retarded and unfit
You must means individuals who don't use Oxford commas.
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>>10368703
Pretty much this, horseshoe crabs have attained perfection /thread
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>>10378480
He's saying things don't change because the ones that DO change are less likely to reproduce.
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>>10368668
slow metabolism.
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>>10378480
You can restate it in a better way as
>things don’t change because they don’t have to change because their environments don't change.
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>>10368668
They don't. Evolution invloves mores than gross anatomy.

And even there, you can see changes in the horseshoe crabs over time.
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>>10368668
it hit the max level
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something else I haven't seen posted in this thread, but generally things wanna mate with their kind. mutations happen for sure, but this behavior happens in many cultures from animal to white supremacists
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>>10368668
Welfare and EBT.
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Why do certain species stop evolving?



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