[mekoka]

I think it might be more useful to look at the author's claim from the other side of the lense. We do carry around barely useful traits, like resistance to toxins that we seldom come in contact with. We can assume that carrying such traits is cheap. If resistance to tetrodotoxin was one such cheap trait, it might have been more prevalent, but it's not so, it could be inferred that it's expensive. Or at least, not cheap.

[xenadu02]

This is another case of a huge fallacy humans seem endlessly afflicted with: The Root Cause Fallacy.

You are assuming there is but one cause for development and/or loss of resistance.

There may not be much pressure to develop resistance to tetrodotoxin for most species. Simultaneously there might be a higher metabolic cost to retaining it for some species but not for others. It is also possible that resistance with low cost is very rarely lost which is why we carry resistance to toxins we don't often see but population bottlenecks in ancestral lines can cause loss of a trait to propagate - even by accident. And much like Vitamin C loss if it doesn't matter the loss sticks. We should not forget that there are multiple resistance mechanisms as well: an immune system generally primed to fight certain common causes of mortality can, entirely by accident, also be primed to recognize and destroy certain proteins conferring resistance to some toxins and not others.

I have barely scratched the surface above. The random walk of evolution and its constant hoarding tendencies should make everyone skeptical simplistic mechanisms of action as well as "just so" explanations of evolutionary history.

FWIW most things are multi-causal. I previously made the same argument about house prices. People who claim it is caused by foreign money, low interest rates, restrictive zoning, etc all want their pet theory to be The One True Reason. In reality the market is complex and many of the proposed causes are merely contributing factors.

[mekoka]

> You are assuming...

I made no assumptions. As I pointed out to another commenter, you might be in too much of a haste to play at being a contrarian. It might be more useful to pay closer attention to what you're objecting to.

Evolutionary game theory demonstrates that evolution is a matter of fitness payoffs. If cost of a trait increases, fitness is reduced. The prevalence of a trait in a fit population is indicative that, at best, the trait increases fitness, at worst, it doesn't hinder it. In both cases, the genes tend to be passed on and the game is allowed to continue. When carrying the trait becomes costly, there's pressure to get rid of it (through the usual evolutionary means).

The above model encompasses all the unnecessary specificity you tried to bring into the matter. If you object to it, address your concerns to the scientists that are leading us all astray.

For now, let's circle right back to the author's original argument. Absence of an actually useful trait to increase fitness (i.e. protecting ones from certain food sources and others from predators) might be indicative of a hefty tax to pay for carrying it.

[kylebenzle]

As a biologist, reading your comments is deeply distressing :(

[zxexz]

Isn’t evolutionary game theory a behavioural model from the 1970s? Not that it’s not interesting; I don’t see the relevance here. Maybe it’s just your condescending tone.

(No offense, I hope you don’t realize how you are coming across, or that if you do this comment will trigger some introspection)

[mbonnet]

You need to accept that you don't know what you're talking about.

[jkman]

Jesus man, your hubris is astounding. 'I made no assumptions'? Ridiculous lol

Behave yourself

[pegasus]

That resistance to toxins we don't encounter often enough to constitute selective pressure, we carry around only if it's the accidental byproduct of another selected-for trait. Otherwise entropy would take care of it, sooner or later. Parent is right, evolution doesn't pay an annual subscription fee for some service which was useful in the past and might come in handy in the future.

[mekoka]

You may just be trying to disagree with the author for sport.

> we carry around only...

Not true. We can carry resistance to some ancestral pressure which isn't part of the current environment.

> sooner or later...

Yes, sooner when it's costly, later when it's less so, through normal evolutionary pressure (entropy and all).

The point is, most species at time T do carry traits that aren't that useful to them anymore. The costlier ones yield enough negative fitness points in evolutionary game theory to rid the gene pool of them quicker. It brings us right back to the author's original argument.

[catlifeonmars]

It would be interesting to see how toxic these newts would remain if the garter snakes were eradicated. If this was indeed a costly trait, we should see a drop in toxicity over a long period of time (possibly evolutionary time). To rule out coincidence, you could follow multiple lineages as they speciated.

In fact, looking at related newts whose ancestors were toxic (assuming the trait is not novel in these ones) would give us some idea as well.

[pegasus]

In the context of TFA, are you sure it's not GP who's arguing for sport? Maybe this clarifies the issue: one way to reword the root (critical) comment is "of course there is a cost, since entropy is always exacting a price". There's constant upkeep necessary for any trait if it is to be preserved. It points out a glaring blind-spot in the article.

[zxexz]

(I agree with you)

It’s funny how often this sort of thing comes up. I’ve always felt that “biology” as a field was unique in the way that it is often taught. Bio 101, etc. - most of undergraduate biology - is often taught with this sort of sweeping worship of the process of evolution in a way that leads to it transcending rational thought. Natural selection is very real, and it’s also such a sorry excuse for an evolutionary algorithm :D

It’s been a long time since my first bio classes so I can’t remember the way I was first taught it, but I do remember all more advanced bio literally being told to unlearn what we had already been taught.

[kylebenzle]

You really seem to lack any understanding of how evolution or biology work :(

[Retric]

It’s not some binary thing but degrees of adaptation.

People can handle significantly more of a wide range of plant toxins like theobromine and caffeine (both found in chocolate) which harm more pure predators like dogs in very low doses, but where rare for out imitate ancestors.

Cattle, deer etc however can handle many of those at much higher doses.

[nkrisc]

> like resistance to toxins that we seldom come in contact with.

Is that because resistance to those toxins was strongly selected for in humans, or because the source of those toxins did not strongly select for effectiveness in humans?

[kylebenzle]

You wildly misunderstood the topic being discussed and user above you is correct.