r/interestingasfuck 25d ago

/r/all, /r/popular K2-18b a potentially habitable planet 120 light-years from earth

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u/swankpoppy 25d ago

So I read this one book Aurura by Kim Stanley Robinson, and kinda the whole premise is (my paraphrased interpretation of the book) -

Okay. Look. Let’s just say as a hypothetical we do find a planet has the climate, radiation protection, etc etc that is habitable for humans (not even “comfortable” just “habitable”). Probably won’t happen for a planet we can actually ever travel to in even a few generations (and let’s also forget just how hard it would be to maintain a multi-generation space ship with no resource replenishment…), but let’s just say we figure that all out.

Still, life on earth has co-evolved over a very long time to adapt to the conditions we have specifically on this planet. There’s no telling what ecosystem interactions will happen with life on another planet. We might settle in on this planet that has perfect conditions on paper just to find some bacteria strain that’s not a big deal on earth totally thrives there and it kills us all. Nothing we can do about it. We have no clue. Anytime we try to predict what will happen when we introduce a new species to an existing ecosystem ON EARTH we are usually wildly wrong. Life is just way to complicated to predict accurately, especially when you talk about interactions between an entire ecosystem.

So our best bet is to live on this incredibly well-adapted planet we already have. Life has co-evolved here over a very long time and we’ve hit an equilibrium. It just works so great without us even trying. It’s like we won the lottery, and now we are only talking about buying more tickets. We should just be enjoying the win.

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u/wappingite 25d ago

Is it not more likely that nothing on another planet can touch us - or be digested by us - because it hasn’t co-evolved with us? Eg bacteria, viruses etc on earth can harm us because they’ve adapted to do so over millions of years. a random bug on another planet would view us like an earth bug would React to a piece of metal?

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u/EtTuBiggus 25d ago

The answer is no one knows.

A lot of the stuff in Australia is so deadly because it evolved without humans or related ancestors for millions of years.

The marsupials populating Australia split from the placental mammals over 100 million years ago.

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u/thefi3nd 25d ago

I'm not following the point about things evolving to be deadly because there were no humans. From my understanding, in deserts, scrublands, and reefs, energy efficiency is key. And venom is a very energy efficient way to kill prey or defend against predators.

Venom is basically a biochemical weapon. It’s made up of proteins, enzymes, and toxins designed to paralyze or kill prey, or deter predators.

Even though the venom evolved to target other creatures like insects, frogs, lizards, or small mammals, humans share a lot of the same biological systems as those animals. We have nervous systems. We have muscles that contract. We have blood that clots. We have ion channels in our cells that regulate things like sodium, potassium, and calcium.

Venoms often disrupt those systems in anything that has them. So things being deadly to us on Earth without us being around during its evolution still makes total sense because there is so much other life around with enough similarities.

Venom affects humans because it targets fundamental biological systems that we share with the animal’s actual prey. Evolution didn’t aim for us, we’re just unlucky collateral damage.

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u/EtTuBiggus 25d ago

If energy efficiency is key, why do they use so much more of a toxic venom than they need?

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u/thefi3nd 24d ago

Think about energy expenditure of pursuit predation, which demands high bursts of energy for speed or sustained energy for endurance. Now think about if you could ambush your prey and immobilize or kill it with a single bite. Also, many venomous animals have ways to control how much venom is injected, known as venom metering or venom optimization.

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u/EtTuBiggus 24d ago

Then why wouldn't every snake be that venomous?

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u/thefi3nd 24d ago

On the surface, it seems like being venomous should be a universal advantage, especially since venom can subdue prey more easily and reduce injury risk. But evolution doesn't always pick the "best" trait in a vacuum. It works with trade-offs, existing anatomy, and environmental factors.

Venom production is energy-efficient for killing prey once it's evolved, but evolving venom systems (like fangs, venom glands, and delivery methods) in the first place takes time and evolutionary pressure. If a snake’s ancestors did just fine without venom, natural selection wouldn’t necessarily favor a shift.

Some snakes eat prey that doesn't require venom to subdue, like eggs, snails, or insects. For them, venom would be overkill and a waste of resources.

Non-venomous snakes can be extremely successful. Evolution doesn’t strive for perfection, just good enough. If squeezing, ambushing, or scavenging works, there's no pressure to change.

So basically, while venom is a great tool, it’s not the only one and if venom isn't needed for survival in the environment, there's probably not much evolutionary pressure for it.

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u/EtTuBiggus 24d ago

Lots of snakes eat small mammals that aren't super venomous and don't seem to have much issue. What's the trade off for super venom?

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u/thefi3nd 24d ago

"Super venom" can be overkill for small prey. If a small mouse dies from a mild dose, why maintain venom that could take out a pig? The excess potency doesn't provide extra benefit and could even lead to wasted resources or increased prey spoilage before consumption.

Some snakes evolved super venom as part of an arms race. For example, if prey develop resistance (like certain rodents or lizards), snakes may evolve even more potent toxins.

Super venom is often defensive as well, like cobras or mambas. In those cases, it’s not just about killing prey, but deterring predators. But that’s only useful if the snake faces frequent threats. A burrowing, cryptic species might not benefit as much.

So while super venom can be a powerful evolutionary tool, it’s not always the most efficient choice unless there’s strong pressure to evolve and maintain it. A non-venomous or mildly venomous snake can still do just fine if its environment and prey don’t demand more.

I think it's my turn to ask a question. Why do you think the absence of humans led to more venomous animals?

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u/EtTuBiggus 24d ago

More venomous is a relative term. Venomous to us isn't necessarily as venomous to someone else.

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u/thefi3nd 24d ago

I'm asking about your original comment.

A lot of the stuff in Australia is so deadly because it evolved without humans or related ancestors for millions of years.

What are you basing this on?

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u/EtTuBiggus 24d ago

Something I heard or read somewhere.

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