Lots of seeds pass through mammals and then germinate in a nice rich pile of mammal poop. More than in bird poop, i think, although there is some tree that was threatened with extinction due to not having dodos to eat their fruit. I vaguely recall there was an effort to get turkeys or something to “process” the seeds?
Did primitive mammals have more advanced homeostasis than their contemporary feathered dinosaurs, though?
Tambalacoque, although the dodo connection is not favoured any longer. Might have been giant tortoises, or a parrot, or something else.
If we didn’t cultivate them, avocados would also probably be extinct, because their megafaunal dispersers died out/were killed off. They’re not the only plants with that kind of relationship.. Lots of plants were once dispersed by megafauna that are no longer around, and if we don’t have a use for them, they can be in severe decline.
I agree for the most part.
Recent research seems to place dinosaur metabolism as neither ectothermic, (cold blooded) or endothermic (warm blooded), but somewhere in between: mesothermic. So, I believe dinosaurs may have endured ice ages (and other stressors) better than reptiles and other cold-blooded creatures, but mammals would have eventually out-competed them. I envision parity between mammals and small to medium sized dinos for some time, with mammals coming out on top at some point in the past.
So, maybe instead of @Stranger_On_A_Train ‘s Kentucky Fried Rat-eating dinos wearing seersucker suits, we’d have Kentucky Fried Velociraptor-eating humanoids wearing leisure suits.
And even though the Jurassic park movies are now historical dramas, they still use dinosaurs from the Cretaceous period.
It’s more that dinosaurs likely had a wide range of thermoregulation strategies. Birds are certainly true endotherms, and they’re dinosaurs. Non-avian dinosaurs were what the term mesothermic was coined for, but there are even some mesothermic mammals.
Yeah that is interesting as well - with plate tectonics and the shifting of the ocean currents distributing warm/cold water changing over time, and the emergence of ice ages, that may have given some mammals a distinct advantage over dinos in some regions. Weren’t the continents all bunched together during most of the dinosaur era?
Thinking about it that way, it makes it more possible for mammals to expand. However, since humans evolved in presumably warmer climates, where dinosaurs would have also been present, I am still not sure we would all be here today if the meteor missed Earth or landed somewhere else.
Pangaea was only around during the Triassic part of that. For most of it, it had broken up and while the landmasses were closer, sea levels also tended to be higher and so there were a lot of seaways.
Well, probably not us, but some intelligent mammalian specie (s) would most likely come out on top, and they would be intelligent. One day perhaps more intelligent than us.
Look at all of Earth’s top predators. I wouldn’t call any of them stupid (not to their face anyway). They are pretty danged smart in the ways they need to be. And as their prey get scarcer, faster, or craftier, they’d need to get smarter still, or perish.
Intelligence is metabolically expensive, but it appears to be naturally selected for quite frequently to different degrees. Imagine a jaguar with opposable thumbs, or an orca with opposable flippers, then give them a few additional million years to evolve. Heck, they’d probably have dark matter and energy figured out by now.
Maybe at first, when the earth started to cool and enter glaciation periods in the first place. But then the dinos would have millions of years to diversify again, and the feathered dinos could grow big while keeping the feathers.
Dinosaurs of the Avian lineage are common today on every continent, including the arctic circle and Antarctica; they can be found in every biome, including aquatic ones. We know that modern birds all descend from a handful of Cretaceous survivors, so my guess would be that avian dinosaurs would be even more successful and diverse in this hypothetical world.
In our world, birds had replaced pterosaurs in the small flying niches, and pterosaurs in the late cretaceous may have grown so large in response, filling niches at larger sizes than birds, while small pterosaur diversity fell. Without the KT extinction, I think larger pterosaurs survive longer, but not until today; I doubt they’d survive the cooling events. A potential exception could be the large bodied azhdarchid species that may have been terrestrial hunters; if they continue down this path, even becoming flightless, I could see them survive bird diversification.
In the oceans, we already saw pliosaurs decline and be replaced by mosasaurs (who are lizards). As I understand it, the ocean ecosystem suffered what was basically a total collapse when dust from the impact and ash from the ensuing fires stopped photosynthesis for a long time, and top predators like pliosaurs and mosasaurs died because their food chains died. If that’s the case, marine reptiles would probably stay dominant for a while. How they’d fare when oceans cooled is up for debate; according to this paper, they migrated into high and low latitudes during summers in the Cretaceous. Would this mean they could survive in equatorial waters during glaciation events? I won’t pretend to know.
If not marine reptiles, then who might live in the sea? Avian penguins are already most of the way there, and I could certainly imagine larger aquatic avian lineages develop during cooling periods, especially since some of the bird lineages that died in the KT event may have been aquatic. Mammals and their relatives did manage to colonize aquatic habitats during the Mesozoic (eg Castorocauda) so it wouldn’t surprise me to see creatures resembling our otters, seals, or even dolphins or whales. It all depends on how well the marine reptiles can handle cooling waters (although as we saw with mosasaurs, a new lineage can colonize and even dominate the oceanic food chain while existing groups are still present, and groups can disappear even without a mass extinction, like the Ichthyosaurs who even had a last burst of diversification in the early Cretaceous before dying out 90 million years ago).
On land, while many dinosaur groups were in decline, others were not. I think the end of the Cretaceous was coming anyways, and a reshuffling of dinosaur groups would follow; but that happened many times throughout the mesozoic without them all dying out.
Dinosaurs (and not just small feathered ones) lived absolutely everywhere, including the arctic and antarctic; they lived in regions with long period of darkness, and where it apparently snowed. So I don’t think the glaciation would have killed them. They’d have adapted. Could they have survived Antarctica freezing over 35 million years ago? No, but then, neither did any mammals. Only a handful of semiaquatic mammals (and semiaquatic avian dinosaurs) live there today, and that’d probably be how things go in our KT-less world.
I think Earth today would mostly be populated by dinosaur groups, but only a handful of the ones we know about would still be atound. Pterosaurs, if they’re around, would be very rare. Avian dinosaurs would be even more diverse and common than they are today. Non-avian dinosaur groups would undoubtedly have shuffled around a few times, but I doubt they’re going anywhere.
Mammals may or may not have colonized the oceans, and in polar regions, they would be the main competitors for birds, likely growing larger than they did in the Mesozoic.
I realized I didn’t mention intelligence. That’s because I think the “dinosauroid” idea is patently ridiculous, and assumes that evolution is naturally geared towards building US. That is ridiculously conceited. I think there’s no reason at all to think that intelligence would arise in the 66 million years after the extinction event.
Could some other lineage, maybe Avian, maybe Mammalian, develop intelligence eventually? It’s certainly possible, but I don’t think there’s any evidence for this. Rare intelligence is likely a Great Filter from a Fermi Paradox perspective; whether it is the Great Filter remains to be seen.
Oh, yes, sorry, I meant the feathered dinos who were mid-sized at the time of impact. I agree that lineage could subsequently also produce megafaunal descendants.
I would. At least, relative to omnivores, they’re dumb as dirt. Pure carnivores, I mean. Bears and wolves not included.
Cats? Orcas? Not intelligent? I’m not including non-mammalian predators. Indeed a lot of those are dumb opportunists.
I do find it interesting that a mollusk (octopus) evolved high intelligence. Makes me think the pathway to intelligence may not be such a Great Filter in the universe.
I meant as a whole group. Sure, dolphins and felines are smart. Chimps and orangutans are smarter. And 8 billion humans skew that even more.
I don’t think it’s a Great Filter, myself, but all of those non-hominid intelligences seem to have capped out at levels way below what I understand to be meant when someone says “more intelligent than us”. It’s not a given that any species will continually involve to be more intelligent.
Something becomes as intelligent as it needs to be to thrive in its environment.
I think it requires some special circumstances for that to require advanced things like reading, writing and arithmetic before such traits are selected for.
Not that it could never happen, obviously it did at least once (or maybe a bit more, depending on how far back in our hominid ancestors we want to go), but it is not something that is inevitable to happen.
Why our ancestors started selecting for a more general intelligence, rather than just what is necessary to catch prey or avoid predators, is an active field of study, one that is currently still based more on speculation than on evidence.
I have read a little about this, and one conjecture is that human brains began to grow and have the ability to work through more complex problems once humans started eating cooked foods. Not necessarily when humans began to control and use fire, but some time prior to that, e.g. after a wild fire they would seek out animals killed by the fire but not burned to ash, to use as food (early hominid BBQ - maybe cooked food tastes better, too). Cooked food, both animal and vegetable, can release more nutrition than raw in some instances, and a steady supply of cooked as well as raw foods (basically, the same diet diversity we should be eating today) is what led to the evolution of our brains getting larger and able to think and plan for the future.
Not that dinosaurs could not have developed intelligence the same way, but given they have had ~3x the amount of time to do so, and presuming wild fire-killed animals existed during the dino era, they did not for some reason.
I suspect our big brains are like the Irish elk’s antlers, or the peacock’s trail. Our ancestors found it sexy.
Sure I agree that intelligence isn’t a given and that a species only needs to be as intelligent as it needs to be to survive, thrive, and continue to have offspring. I was joking about Jaguars and Orcas one day figuring out dark matter/energy, but I think we agree that once intelligence emerges in a species, it may very well give it a competitive edge to evolve a bit more intelligence, and then a bit more…
Of course, this increased brainpower doesn’t come without a metabolic price. Perhaps species A found it beneficial to evolve more brainpower, while species B found it best to put more of its metabolic eggs into more speed, or venom, or something else (not a conscious decision of course). Do I believe any/all species are destined to evolve into intelligent tech species? No, of course not. There’s no destination or direction with evolution. On Earth, I’m confident that it was just a long-shot coincidence that hominids evolved to become technological.
We’re probably the only species that would have, or will be technological on planet Earth. But, basic intelligence is present in many species, and even higher intelligence is present in many others, including our avian dinosaurs (birds). If more intelligence gives them a competitive edge, there’s no reason to believe they won’t evolve more intelligence in the future. I don’t believe the non-avian dinosaurs, if they survived, had the same potential because they (apparently) were mesotherms.
And, while I don’t believe our galaxy (or the universe at large) is peppered with technological civilizations, I believe there must be some out there, only because of the vast potential number of M-class planets involved. Odds favor it, I believe.
And cooking food helps to preserve it for later. Leading to planning for the future, something that humans seem to be much better at.
But how much is chicken and how much is egg is still very much unknown. There are conjectures that more or less fit with what we know of pre-history, but there are no definitive answers, not even close.
Yeah, it seems they were well fit to thrive in their environment, and there were no selective pressures to further develop intelligence.
Whether those factors would have changed in the intervening tens of millions of years and created a favorable situation to develop larger brains with more general intelligence is a matter of even further evidence free speculation than our own development.
Not that it’s not fun to think about, and productive in its own way of developing our ability to engage in abstract thought, but there are going to be no answers found without a time machine or a portal that opens upon parallel universes.