That's starting from a point almost at the finish line, with intelligent social dexterous tool-using fire-making apes. Really it took our species about 4 billion years. Every other living species has had just as long, and hasn't developed civilisation. There's every reason to think that the extinct dinosaurs, given 66 million more years, would be like every other non-human species.

That got me wondering how long it took social insects to evolve. Did we have massive colonies 66 million years ago? Appears so. [0]

[0] https://academic.oup.com/mbe/article/32/2/406/1054064

I'd listen to this thread as a podcast

Is it inevitable that given enough time, the dominant life form in a sufficiently hospitable environment will develop higher intelligence and civilization? I'm not sure we know whether that's the case or not.

Life has existed on Earth for at least 4 billion years --- it seems to have emerged within 500 million years of the planet's initial formation.

Complex life --- multicellular life with differentiated structures --- took another 3.4 billion years to form, emerging only about 600 million years ago.

Much of the biological hardware and processes for intelligence seems to have emerged with the first mammals (~200 million years ago), particularly emotional-hormonal systems that seem broadly common. It still took most of the intervening time for clever apes to emerge (about 2 million years ago), with anatomically modern humans showing up 200,000 years ago. When language developed isn't clear, but likely by degrees somewhere between 2 million and 50,000 years ago.

(There's a great presentation on the anthropological evidence of complex thinking in this 2012 presentation by Sander van der Leeuw: https://yewtu.be/watch?v=pOyQqPi28ug 69 minutes, most of the meat is in the first 20--30 minutes, high-density information.)

And modern technological society is really about 200 years old, with "peak invention" being variously defined, but the 50 to 100 years beginning about 1875 would be a good choice.

So: over 4.6 billion years, life has existed for over 4 billion, and developed complex and technological intelligence only within the past 1 million years, and quite possibly substantially less. That's 0.02% of the total time.

Earth itself will remain generally habitable for only about another 800 million years. If humans or other intelligent species survive over that period, they'll still account for less than 15% of the history of life on Earth.

Considering intelligence to be inevitable is ... somewhat poorly supported, at least based on that timeline.

(Related, see the Drake Equation, and yes, we're working with a single sample study and numerous unknowns.)

Just wanted to say that comments like this are what makes me return to hacker news every once in a while. Thanks!

“Dominant life form” is not really a well defined concept.

I assume you would say humans are the dominant life form of the present day earth, and many would agree with that. Ants are more numerous, cattle and antarctic krill are heavier by biomass so clearly such simple metrics are not what we are after.

And clearly back when humans started developing “higher inteligence” they were just funny monkeys running around the savana harased by jackals left and right. Very much not a “dominant life form” in any sense of the word. One could attribute any special significance to them only in hindsight by what they become, rather than what they were.

True, more a matter of the intelligence resulting in dominance than the reverse. I think you could define dominant as, basically, top of the food chain - able to kill any other animal it wishes to, and able to defend itself from all others. It would certainly be possible to be dominant without high intelligence, but it seems unlikely it would be possible to be dominant over a competitor that has a significant intelligence advantage, assuming the competitor survives long enough to exploit it.

But the question is, does that mean that if such an evolutionary path is possible in a given environment, it will always eventually occur? My guess would be yes, but I'm certainly not 100% confident. ('Eventually' meaning, say, within a hundred million years. Presumably given infinite time, everything possible would occur, so that's not really interesting.)

This is true. Even though some species excel in certain areas (beavers are good at building, dolphins can communicate), no other species come close to human intelligence.

We don't know if there's some special sauce that makes humans unique.

Dinosaurs were the dominant species (including the sea), unlike sharks.

Also worth considering that humans became the dominant species after developing civilization or maybe by developing civilization.

Even pre-civilisation humans were having substantial impacts on local landscapes and ecosystems, particularly in terms of out-competing other top predators.

"Civilisation" defined as "having established cities". Arguably much of North America and Australia would be pre-civilisation by this definition. There are some exceptions among Native Americans in North America, but most cultures seem to have been tribal and reasonably nomadic or based in small villages lacking the complex social and economic structures, as well as trade and diplomatic relations associated with cities. Pueblo culture would be the obvious exception, possibly also mound culture (Illinois / Mississippi Valley). This is not an area of expertise for me.

And my point remains that even without signifificant cities or intensive capital, these cultures had profound iimpacts on their landscapes and were clearly an apex species.

I thought dinosaurs were not adapted to aquatic environments? Marine reptiles like mosasaurs, plesiosaurs and ichthyosaurs were not dinosaurs. Spinosaurus, though, was semiaquatic.

I mean, Dinosaurs weren't a species.

This is a pedantic dismissal of the comment above. We all understood what he meant.

If your intent is to educate HN on the difference between species, genus, family, order, ..., perhaps do so more constructively?

I guess I just felt that there was quite a large number of dinosaur species for civilization to arise in, not to mention they were on land, so it might be weird to say sharks didn't develop civilization over a long period of time given the differences compared.

But I suppose you didn't understand what I meant.

I don't think any of that was conveyed by the phrase "Dinosaurs weren't a species" :)

I guess I do have a tendency to not specify everything but to just leave some things as implied, that said I think the amount of dinosaur species vs. the amount of shark species is strongly implied when saying dinosaurs is not a species in context.

The land thing was not as strongly implied but again one might consider it when thinking yeah dinosaurs aren't a species, neither are sharks but the numbers don't align...hmm,hmm oh yeah and also the dinosaur species covered many more possible environments.

Haha I do that too sometimes. But for perspective, it's quite a leap for me (and it seems most others reading this too), and not at all "strongly implied" by your statement, even in context. I'm sure that chain of inference might be natural and automatic with your style of thinking, but my mind naturally goes down a completely different path when confronted with your initial statement, so it's probably best to elaborate what you're actually implying to avoid miscommunication :)

To be entirely fair, neither is "shark" a single species...

But yes -- my point was that no shark species formed a civilization over that vast period, so it's hard to say whether any dinosaur species would have.

ok, fair enough.

But the plural of "species" is "species". When you are talking about one species, you say "species". When you are talking about multiple species, like all the species of dinosaurs, you say "species". "Dinosaurs were the dominant species" is correct, talking about multiple species. "Humans are the dominant species" is correct, talking about one species.

ok well I had to upvote that, despite it pointing out I'm an idiot.