27:12 Actually except the Mesosaurs, there were marine Temnospondil amphibians and with new finds from Spitsbergen it appears that the Ichthyosaurs had their start in the late Permian, survived the End Permian extinction and diversified into the Triassic, so there were secondary aquatic tetrapods even back then.
As someone who has been doing a series of videos on prehistoric life I do agree that this trope does seem overplayed. I do wonder given your videos if you would ever consider doing a video on trilobites. I think it could be interesting to discuss the assumption that earlier life must inherently be inferior, ie trilobites were doomed to extinction while other arthropods prospered. And if that's really true. Plus could be cool to talk about some of the tropes associated with them both in spec evo and paleoart I know this is an older video so you might not see this comment but your videos are very thoughtful
One big problem(perhaps several) I have with this idea is that birds have small heads. It's been ingrained in them for a long time and with a small head therefore it'll be hard for them to develop the proper jaw size to compete in the sea. Birds have also evolved to be light creatures, hollow bones, wings, small heads, thin sharp beaks for most of them. They'd have to radically change to truly fill that niche which I don't think they'd be able to do honestly. I also like your view on this, marine mammals are in fact that best terrestrial tetropods to have evolved yet, should they all go extinct for some reason, i don't see why birds specifically rather than reptiles or other mammals evolving towards the sea, or perhaps fishes or cethlopods might lock that niche away from theropods. Marine mammals(especially cetaceans) are in their place of the dominance in the sea for a reason. Ig they only thing that'll truly eliminate them is either a KT level or perhaps a Permian level event, or if we want to do it easily and quickly just make humans do it, they're far more dangerous than any volcano or meteorite.
Can't believe you didn't address the fact that cephalopods cannot become terrestrial since they'd have to go through a freshwater phase, which they are incapable of.
Would the presence of humans really prevent biodiversity (including megafauna diversity) from bouncing back? Prehaps humanity can develop a society that can coexist with nature.
The attitude of pushing the blame onto humans for future mass extinctions kinda makes it seem like the author is dropping nuance and the potential humanity has to right our wrongs in order to present a narrative. Like, I understand if you're just interpreting it through a fictional lens, but as far as science goes, conditions are subject to change, so why is humanity getting its act together any less strange as birds replacing marine mammals for said authors?
Nice video and for me It seems that the only for birds to frill the niches of marine mammals is a seedworld like Serina as their won't be any competition for the niche.
22:04 I’m not sure this is a good argument. You could have said the same thing about mammals evolving to fill bird niches, if you lived before bats evolved. About anything, really, before they evolved to fill a new niche for the first time. Regardless, I’m sure it’s not unimportant that birds have never evolved precocious ovoviviparity, which would seem to be required for any of them to become fully aquatic. That would probably have to happen first, before any new niches open up for them.
What if fully aquatic oviviviparous sea bird or water bird decendents evolve in other places besides the oceans like in lakes, rivers or some seas independently and then, for a while, coexist with future cetaceans, pinnipeds, or any future mammal competing for the aquatic niche?
Fantastic video. There's been a strange "backlash" against mammals in Spec Evo that part of me blames on the desire for projects not be be seen as "mundane" while another part of me sees it as a backlash against the older idea of mammals being superior to "less evolved" animals like dinosaurs.
I think another part is that people often overlook smaller animals just because sea birds aren’t marine mega fauna doesn’t mean there not successful given how diverse they are today
I think its the backlash to the idea that mammals are the "most advanced" compared to dinosaurs @@troutinspace5427 all animals that are alive are successful honestly. Life is hard.
I never knew that the babookaris were meant to be the last of the primates? The Future is Wild was originally gonna be a prequal/sequal to After Man, which had multiple primate species.
Honestly great video! I do wanna ponder fully aquatic birds in a speculative context. But on another question that you may have gotten before, given your knowledge on the topic. If your cool to respond despite it being a little unrelated. What is your thoughts on certain big spec evo projects if your knowledgable on much of them. Like Kaimere, Serina, or maybe even some of the many startups popping up. Though to get a bit more out there and general with the question. What is your thoughts on a speculative evo sonario of Mesozoic fauna [66 million years ago pre asteroid] vs Cenozoic fauna [about 1 million ish years ago. Modern but before our current extiction/the expansion of man]. As time examples as those tend to be the most common rough times where the two worlds speculatively butt heads. Either case sorry for the somewhat possibly loaded question but still loved the video, and it was quite informative in how I may go about things.
The penguin whale was one of the two creatures from After Man I had major issues with (the other being the parachute gliding shrew). With the penguin whale you have two issues. The first being that no birds give live birth. The second being that penguins hatch covered with down and grow waterproof feathers as they mature. This two facts made the penguin whale seen especially unbelievable,
Also, competiton between mammals and large seabirds doesn't mean they can't co-exist. Giant penguins and plotoprrids co-existed with whales for several tens of million years
3 other extinction events larger than 4 of the big 5 occurred as far as extinction rates go, but no one mentions them. ~ 520 MYA, ~ 500MYA and ~260MYA. What is the reason(s)?
Thank you for the excellent breakdown of this complex and interesting topic. I always viewed this trope as lazy and unrealistic. Some may argue that certain sea birds already compete with whales for krill and schooling fish, they just do it in their own way: they are numerous and small, often finding the bait balls and krill swarms faster then the whales. I wonder if biomass of the seabirds is actually greater than that of the whales feeding on similar foods (I believe Darren Naish mentioned something like this on his podcast). In any case, even when birds feed on the same food as whales, they do not evolve similar features. There is also the viviparity thing. It is unprecedented in birds, and I think it will take them an unreasonably strong selection to gain it. Mammals are simply “preadapted” to becoming fully aquatic with their preexisting viviparity. Finally, I wonder how viable modern bony fishes for replacing cetaceans, especially when taken into account ability to breath air and limited endothermy in some of the modern groups.
@@pumaconcolor2855 but they haven't taken over from cetaceans as megafauna per se. Sea turtles occupy completely different niches to marine mammals with the closest convergence being with sea cows.
Honestly, i think it's far more likely for loons to evolve into a fully-aquatic form than penguins, in fact, they are already kind of becoming one, since they literally cannot walk with their legs, and besides that, i think that their buoyancy and their flexible necks would help them fill a niche distinct from cetaceans and pinnipeds.
They can't walk because their legs have shifted horizontally in order to be better swimmers. Penguins are more marine than them, and it seems wing propelled divers get better at reaching larger sizes, like extinct penguins and plotopterids
@@Carlos-bz5oo Yes, but since penguins can still walk and stay on land, while loons are just as clumsy as a seal, i believe they have a better shot at eventually becoming >fully aquatic<.
@@Carlos-bz5ooThey lay their eggs on buoyant nests, meanwhile penguins have to lay their eggs on dry land. In a way, loons are ahead of penguins when it comes to aquatic reproduction. Also, animals like mosasaurs, plesiosaurs and ichtyosaurs descended from egg-laying reptiles, and have each evolved live birth independently from each other, so there's nothing stopping birds from evolving the same.
@@darkonyx6995 Birds and turtles have hard-shelled eggs; they cannot get rid of them, because they rely on the shell's calcium deposits for the embryo to develop a skeleton. Remember, aquatic birds have had since the Cretaceous to produce viviparous forms, yet none did.
What do you think of the possibility of crocodiles or monitor lizards to evolve to be semi or fully aquatic marine animals which would locally outcompete marine mammals in areas of very low ocean productivity and warm water, due to their lower metabolisms?
In tropical areas reptiles are more prominent but mammals are still dominant. But if we look to the past marine mammals did share the oceans with some pretty large marine reptiles like rhamphosuchus and paleophis colosseus so while I don't think a warmer climate would eliminate marine mammals I do think some giant marine reptiles could find their place in the seas.
@@wolfpackastrobiology3690 Yeah that is true. Are there currently large amounts of pinniped colonies on Australian and Oceania coastlines tho? We do notice that pinnipeds, when presented with limited amounts of food, evolve to be smaller, as with the Caspian, monk and nerpa seal, tho this mainly applies to closed bodies of water. In the case of the Caspian and black seas, the beluga sturgeon l, due to its lower metabolism, came to be the most massive macropredator (reaching up to 7m) in those bodies of water instead of a marine mammal, until humans caused it to be doomed to certain extinction(tho seals in the black sea and Caspian also bece nearly extirpated. I could imagine such a case happening on other areas of the globe assuming pinnipeds continue to suffer due to overpopulation and global warming destroying their nursing habitats
Honestly sea snakes are really slept on in these discussions. They're doing super well right now and never leave the water for anything(Hydrophiines, not sea kraits).
The explanation for humans becoming extinct in the end would be due to mass starvation due to collapse mass desertification, urbanization and collapse in marine food resources, and mass infertility caused by microplastics and industrial pollutants, which accumulate generationally and damage the genome. Since the human reproductive system is relatively vulnerable to pollutants compared to other animals, these other animals would survive. Another plausible possibility of human extinction cause would be particularly infectious prions(such as a human equivalent to scrapies), due to to medical research being unlikely to ever be able to treat prion diseases.
I think the main thought processes behind the belief that anthropogenic climate change will cause mass extinction among all marine megafauna are: -its not only climate change but pollution and overexploitation of marine resources. The thinking is that within 200 years, the oceans will become so polluted with things such as microplastics and fertilizers, that whales and their prey species won't have enough time to adapt to them since the ocean got concentrated so rapidly with them. -overfishing of animals like sardines, herring, krill, anchovy, assuming it continues at the current rate, will cause a complete collapse in their population, due to current estimates that up to now, they have lost 40-95% of their original biomass due to human harvesting. Thus, from there comes the thinking that all whales will become extinct due to not only environmental changes but competition with humans. We see how overfishing has caused starvation among otherwise cosmpolitan whale populations, such as orcas around puget sound, due to the local extinction of salmon there. -if humans in alternate history continued industrially hunting all whales at rates of the 1930s-1940s(like 170000 humpback whales killed per year for example) for their oil and meat, one can assume, that within a century the vast majority of whales would become extinct, with the possible exception of porpoises and dolphins(though they were industrially hunted for meat too), and t6his would open niches for other animals once humans go extinct. -most whale species evolved in cooling climate(which cooled slower than the planet is warming now), so it would be hard for them to evolve in the reverse. Ocean acidication and disruption of ocean currents would cause nutrient upwelling to drastically reduce, thus dooming most baleen whales. What do you think of these factors?
As for overfishing, while it would have posed a serious problem to the population of great whales 200 years ago, now their population is so low they can easily sustain themselves on what's left. Not to mention that many of the large baleen whales nominally hunt krill which is hardly a staple seafood. But as for pollution, yeah it's a problem to pretty much all marine animals high on the trophic level but seabirds aren't exempt in that regard. Not only that, some populations of Dolphins have fairly low trophic levels (down to 3.25) so while pollution can and indeed does take a heavy toll on marine mammals, I can't see it wiping them out: www.int-res.com/articles/meps_oa/m699p167.pdf As for having evolved in a cooling climate, so did everything else since the Paleocene-Eocene Thermal Maximum but that doesn't mean that they're doomed if the weather gets warmer. On top of that, many modern marine mammals like spinner dolphins live in the tropics so I doubt a warming climate would doom them.
@@wolfpackastrobiology3690 Arent staple foods of both baleen whales and toothed whales, such as herring, salmon, mackerel, albacore, sardines, still crashing due to unsustainable fishing practices due to ever increasing demand in developing countries?
Honestly there’s quite a few spec Evo tropes “bird whales, predatory rodents or primates, domesticated animals dominate” that are probably better off as seed worlds
40:27 Was this video a whole powerpoint presentation?! On a more serious note I love videos like these talking more in depth about specevo tropes! Much like the Unnatural History Channel you both have a number of points on how to do animal biology more accurately. Instead of following previous works like gospel (AfterMan/FisW), criticizing them is important as well. Videos like this may slow down my own specevo project, but at the same time I'm grateful for the information within them! All in all great video, I hope you get more subs, and why weren't Mosasaurs mentioned?
Nice review. I am no fan of GH's ideas. They aren't original. In the last thirty years all fields of science have advanced and many things that were once believed have been shown to be different. During this same period Hancock's claims, despite all that has been discovered, have remained largely unchanged.
Also, we can utilise neuromuscular stimulation to minimize atrophy (and even then they will have to deal with less gravity than they would hear on earth). pubmed.ncbi.nlm.nih.gov/25296344/#:~:text=Neuromuscular%20electrical%20stimulation%20prevents%20muscle%20wasting%20in%20critically%20ill%20comatose%20patients
lol Don't expect NASA to ever make that happen. they can't even get samples back from the dog turd maker they have roving dropping samples all over like dog turds. mission to collets them in a few decades? no we have wars to fund. we will never collect them. Don't worry China is bring samples back in 5 years. But you pretend we are gonna change the planet? And can't get a sample back or ever test for life after all those missions? seriously? Fools!
Shaped charge just entered the comment section. All tanks just left the comment section. Tanks these days have made up numbers for armour thickness against shoulder mounted shape charge stuff. I have heard of claims like 1000-1400mm. Yet all of these armour sections get taken out by 750mm penetrating rounds. I reckon modern tank armour is at its best about 400mm at most against a shoulder mounted weapon.
Always thought the best place for a colony with some work would be to mine down into the top of Olympus mons...it would be a natural bowl to hold in the atmosphere and water u produce...if there's residual volcanic activity u should find warmer rocks and possible gas emissions for pressuring a enviroment admittedly the gases would need processing to be safe. Also if there are precius and rare metals that would be useful for industry the cone of a volcano would be a likely source
I don't understand the argument that humans cann't handle some Months in a tiny space capsule on the voyage to Mars. Valeri Polyakov spend 437 consecutive day in space, that's almost 15 months and he didn't go crazy. He went on to live till 80 and died just recently 2022
Well they would have to go through psychiatric screening to know they'd be able to endure the voyage. This would omit many people who had more useful expertise for exploring Mars itself.
