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Comment by cogman10 | Hacker News Reader

An interesting fact I learned from an evolutionary biologist is that when there's a gap in suitability life has a tendency to rapidly evolve and adapt to that gap.

That's why after mass extinction events, we see explosions in evolution in creatures that had essentially stagnated. Mammals being the best example of this. They went from being small little creatures with little distinction for generations to everything from a mouse to a mammoth. It wasn't until the rapid extinction of the dinosaurs with all the environmental gaps that created that we saw an explosion of different creature types. There were niches to fill.

This is likely part of the reason we see life in such extreme conditions. There was a hole to fill and the creatures best suited to survive in that niche did.

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Also, the interface between mediums, and energy gradients.

Also that this part of the galaxy, and the Universe as a whole, seems to be favourably quiescent.

Slightly tangential, have you come across the terms island dwarfism and island gigantism (also insular -), and did you know the New Zealand Kiwi is the T-Rex’s closest living genetic relative. Here’s hoping it never makes it off the island!

Yes! Islands are fascinating because the creatures that get trapped on them take or represent weird routes of evolution.

It's no wonder that Darwin started thinking "what's happening here" after visiting a bunch of islands.

My favorite island creature is the cold blooded dwarf goat Myotragus balearicus. Likely a victim of human expansion.

Hadn’t heard of that one before.

Sure it was cold blooded? Wikipedia claims it was a mammal.

It is a mammal which is why it's so fascinating!

The goat bones have a growth pattern only found in reptiles suggesting it had adapted to varying availability of food. Other morpholigic changes (smaller brain, smaller eyes) also suggest that it had at a minimum evolved to withstand low nutrition periods.

The working theory to these observed structures is that this mammal a rare example of a warm blooded creature turning cold blooded.

Stranger things have happened though, the evolutionary path of whales is particularly strange.

Reminds me of Adrian Tchaikovsky's new book Saturation Point. I don't want to reveal any spoilers, but it is about warm-blooded/cold-blooded and applicability to quicker adaptation.

> The working theory to these observed structures is that this mammal a rare example of a warm blooded creature turning cold blooded.

I was so excited to read about this, but it turns out further research found that all ruminants possess these structures:

https://www.nature.com/articles/nature11264

> Our study supplies the strongest evidence so far that homeothermic endotherms arrest growth seasonally, which precludes the use of lines of arrested growth as an argument in support of ectothermy.

The neat thing about this goat is how it now is part of a body of evidence that dinosaurs were endotherms.

This is also neat. Thanks for sharing :).

Warmbloodedness and homeostasis are slightly different things. There are mammals that can radically drop their body temperatures (hibernation) as there are a few fish that can raise them (great white sharks).

What lends credibility to the cold blooded theory is that the island is located just south of Spain. Climate wise it simply never gets super cold there.

But certainly it's not proven. These goats went extinct at something like 1000 BCE

Not every gap. The temperature range is rather small, say about 200c. Anything much above boiling water, or below hard freezing, and the life we know stops. Some critters can survive, but they do not thrive outside that range.

I agree.

Just pointing out strange fact of accelerated evolution after mass extinction. There are limits to what earth chemistry will allow for in life, and likely earth's climate and temperatures have been particularly hospitable to life forming and propagating.

Fundamentally we're limited by two things- the boiling point of water, and the fact that biological macromolecules are very complex and fall apart or crumple up at high temperatures. Deep sea creatures can bypass the first one due to the intense pressure in the deep ocean, but you're still going to have to deal with the fact that atoms bounce around and move more at higher temperatures, and that isn't good for the precision molecular machinery that life relies on.

On the low end, we're pretty much limited by the same things, but in reverse- the freezing point of water, and the fact that chemistry slows down at low temperatures.

So that puts us with a fundamental limit of 0-100 C for any system that relies liquid water at atmospheric pressure, and only a little bit beyond that for extremophiles. There is another fundamental limit beyond 100 for high temp when any organic molecule will start to burn or pyrolyze, but the boiling point is already a huge evolutionary hurdle on its own for most places on Earth.

"Life, uh, finds a way"

The problem comes when the niche something fills happens to line up with "this one small pond where someone wants to put an infrastructure project".

If what ecologists tend to want to say is accurate, long term this will lead to a gap in suitability, where humans find themselves in a progressively less suitable environment.

In a similar way to how the solution to inflation is higher prices, it may turn out to be a self righting process.

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