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Evidence that the evolution of mammals began in the Southern Hemisphere
- JoeAltmaier 4y agoIsn't it possible to compare dna between marsupials, mammals and monotremes and figure out which is 'earlier'? The paper described depends entirely on fossils which is good but not a smoking gun.
- masklinn 4y agoSure is, that's the principle of a (time-scaled) phylogenetic tree. But it does not tell you anything about where they came from.
- adrian_b 4y agoMarsupials and placentals are more closely related than any of them is related to monotremes. This is what has been determined from the DNA comparison. Neither marsupials nor placentals are "earlier", they both have a common ancestor. This paper is about that common ancestor, more precisely about the continent where it lived, which now appears to have been Gondwana, in contradiction with earlier suppositions. Gondwana is the former union of Africa, South America, Antarctica, Australia, Madagascar and India. The evolution of mammals has been influenced much more by the breaking and fusion of the continents than the evolution of other animals, because for mammals travel across seas was much less likely to be successful.
- hinkley 4y agoI assume you mean compared to birds? Ferns, wasps and slugs don’t like ocean voyages much, either. Coconuts are adapted to them (and yet the Polynesians had to bring them along to many places they now exist).
- JoeAltmaier 4y agoAfter hurricanes, frequently giant rafts of detritus can travel across the ocean. These sometimes have all sorts of life on them. It is conceivable that would include all of those creatures?
- dotancohen 4y ago> Ferns, wasps and slugs don’t like ocean voyages much, either. Coconuts are adapted to them Are you suggesting that coconuts are migratory?
- hinkley 4y agoOh but they are. They just don’t migrate to central England.
- kuhewa 4y agoMigration is a recurring movement behaviour or pattern, coconuts don't do that. You are probably thinking of dispersal, which is movement that results in gene flow, e.g. into a new place, permanently. That certainly occurs but it seems likely it isn't all that common, coconuts really only needed to disperse as far as the next coral atoll or island, which tends to be as far as a planktonic coral larvae can disperse. Really remote islands probably had coconuts introduced relatively recently by early settlers. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3936586/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3936586/
- dotancohen 4y agoA swallow could grip it by the husk. Will you tell your lord and master that Arthur from the Court of Camelot is here?
- greggsy 4y agoI have a lot of respect for Professor Tim Flannery - he’s a great science communicator and hosted a heap of shows in the early 2000’s. He fronted a parliamentary hearing on climate change some time around 2010, where a heroic Liberal minister stated something along the lines of ‘you’re a palaeontologist, not a climate scientist, so you’re argument is invalid’. It was pretty sad to see. Even being a climate scientist back then was cause for your credentials to be brought into question, let alone one from a cognate field.
- mistrial9 4y agofirst mistake - you take the words of a politician, at one stroke, against a lifetime of disciplined study and speaking.
- poulpy123 4y ago> Liberal minister Not being familiar with Australian politics, is it liberal in the US meaning or the european meaning ?
- erklik 4y agoLiberal party in Australia is the centre-right party. I am guessing they'd still be left of the US right-wing but that's beside the point.
- tw1984 4y agoI personally won't label the Liberal party as a centre-right party or left of the US right wing when it is currently led by Peter Dutton who is a typical far right element in modern politics. I also struggle to categorize its recent former leader Tony Abbott and his close mate Joe Hockey who was the Treasurer as "centre-right". We are talking about a priest who was famously & accurately labelled by the only female Australian Prime Minister as a misogyny - that speech was voted for the No.1 moment in Australian TV history! These two are the people who want everyone to believe that it is a life style choice when people don't buy & drive ferrari. Oh, let's also don't forget what happened to Liberal's actual centre-right leader Malcolm Turnbull. He was replaced by a bulldozer PM who is responsible for the use of automated machines to force the most vulnerable people to fork out billions of $ to cover their non-exist debts so his federal budget can look better to his supporters. Is this centre-right?
- personjerry 4y agoI hate how the article asserts the new theory as fact
- sesm 4y agoKurzgesagt recent video was about quasi-stars, a very exotic hypothetical object described in just couple of papers with 0 proofs of existence. It’s so marginal, that even Wikipedia has a ‘no recent papers on subject’ badge on corresponding article. Still, an entire video was made, as if they were describing an established scientific concept.
- russdill 4y agoThe video made it clear that they are hypothetical, with a lot of, "if they exist"
- marmetio 4y agoFrom the video about 45 seconds in: "but if they existed, they would solve one of the largest mysteries of cosmology" Is that not enough?
- xenotize 4y agoThis video might give you some insight on why they use the research that they use, or rather, the lack of research they use. https://www.youtube.com/watch?v=HjHMoNGqQTI https://www.youtube.com/watch?v=HjHMoNGqQTI
- Dylan16807 4y agoOkay, what billionaires want propaganda about weird star objects? This kind of thing is important with relation to some of their video topics, but what's the connection here?
- whatshisface 4y agoUnless he said they were real in the video I don't see the problem.
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- masklinn 4y agoHasn't that been pretty well established for a while? I thought it well grounded that mammals had evolved on Gondwana (the southern part of Pangea) during the process of it splitting away from Laurasia, and had settled Laurasia from Gondwana Gondwana was composed of now South America, Africa, India, and Australia.
- ttyprintk 4y agoNational Geographic covered it about a year ago: https://archive.vn/YHs1H https://archive.vn/YHs1H
- WelcomeShorty 4y agoFascinating article. "Many paleontologists angrily reject the DNA findings, arguing there must be something wrong with the molecular clocks the geneticists use to date their findings. The geneticists counter that paleontologists just haven't found the right fossils yet." And that should make clear it is not that clear cut as I (with ZERO background knowledge in either area) thought it was.
- brightball 4y agoI think there are certain things that we're simply never going to be able to know with certainty, but it sure it fun to talk about. That Ancient Apocalypse show in Netflix is really interesting along those lines.
- JoeAltmaier 4y agoHm; I thought that Ancient Apocalypse had been debunked here, as a collection of old myths that had been thoroughly discredited, but now presented as current issues. Just an invented-content money grab kind of thing?
- rhodorhoades 4y agoWell… the whole ‘ancient apocalypse theory’ might be discredited, but the sites they visit date back extremely far into our ancient history. It also shows that pockets of architectural knowledge rapidly advanced and then receded all across the known world. One thing is for sure, the human story is far from a ladder, with periods of around 1000 years of advancements and then everything collapses for a couple generations. I think it goes back to the OP’s original point… there are some things we cannot ever know for sure but they are fun to learn and talk about.
- aaron695 4y agoMap of the Earth - https://dinosaurpictures.org/ancient-earth#120 https://dinosaurpictures.org/ancient-earth#120 (Display Options -> "equator" for better context) DOI - https://doi.org/10.1080/03115518.2022.2132288 https://doi.org/10.1080/03115518.2022.2132288
- barbazoo 4y agoThis is fascinating.
- justinator 4y agoAmazing. I wish the dropdown menu was sorted in chronological order.
- kubanczyk 4y ago> Use the ← and → keys to step through time
- psychphysic 4y ago
- legostormtroopr 4y ago> You like lock them up, sterilise them, use them for experiments. Not withstanding that your commentary has nothing to do with the article, as an Australian I am going to request some more information on this. Australia is by no means a perfect country, but your phrasing suggests that First Nations people are currently sterilised or used for experiments. That may have been the case, but hasn't been for many decades. Additionally, First Nations people have access to substantial government programs, including free higher education, welfare and housing programs, and specialised medical support. So please, with less inflamatory rhetoric and more fact, how can you possibly compare Australia with District9 (which was itself more accurately a reflection of apartheid South Africa, not Australia)?
- psychphysic 4y agoI'll abstain from engaging as the original comment was flagged. Guess not a topic for HN.
- Nifty3929 4y ago"Currently taking it with a massive heap of salt as potential biased source" You probably mean a tiny grain of salt. As in: "There is very little meat here, so I'll only need [to take it with] a tiny bit (a pinch) of salt."
- delecti 4y agoMy understanding of that idiom (and how I see it most commonly used) is that the skepticism is proportional to the salt. Slightly suspect things only get a bit of salt and skepticism, hugely unproven things get a lot of salt and skepticism. Given that, an unproven but large claim would need a lot of salt and skepticism Based on the supposed origin of the idiom, I think salt and skepticism being proportional is a bit closer to the original meaning, than them being inversely proportional, though neither is especially close. https://en.wikipedia.org/wiki/Grain_of_salt https://en.wikipedia.org/wiki/Grain_of_salt
- guerrilla 4y agoSo then, all the invasive species are actually indigenous there* ;) * This is a joke; I know how it works.
- permo-w 4y agothis article takes a spectacularly long time to get to the point of what the actual discovery was
- AlbertCory 4y ago(Disclosure: been to Oz three times & I love it) I hate to get all ad hominem here, but the fact that it comes from an Australian journal is just a tad bit self-interested. It reminds me of the Chinese scientists who keep insisting that humans evolved in China, not Africa: https://www.news.com.au/technology/science/evolution/chinese-academics-point-to-fossil-finds-as-evidence-modern-humans-evolved-in-southeast-asia/news-story/759392de611a3c7ffb5e57f97a2d4c1a https://www.news.com.au/technology/science/evolution/chinese...
- somishere 4y agoPoint taken, but where would you expect Australians to publish re a fossil found in southern Australia? In a North American Journal?
- AlbertCory 4y agoAre there not international journals? Peer review by non-Australians?
- twobitshifter 4y agoI got the same feeling, the critical fossil is a type of tooth discovered by the author many years ago.
- MichaelDickens 4y agoI don't know anything about the subject itself, but I don't like that the article makes hyperbolic claims like > Together this weighty band of experts has just published a paper in the scientific literature that’s likely to be seen as landmark in our understanding of life on Earth.
- Konohamaru 4y agoNo wonder mammals are afraid everything's trying to kill them and think everything's poisonous.
- nomel 4y agoThere's a theory that snakes pushed the evolution of our visual cortex: https://en.wikipedia.org/wiki/Snake_detection_theory https://en.wikipedia.org/wiki/Snake_detection_theory
- munificent 4y agoTangential: I spent a lot of my youth wanting to be a herpetologist and traipsing around swamps catching snakes. Many many many hours hunting for snakes hiding in the underbrush. I noticed over time that my visual system would get into this weird state where it was like I wasn't actively focusing on anything, but I could pick up any tiny motion or snake-like shape anywhere in my visual field. It's a really strange but gratifying feeling.
- nomel 4y agoYeah, same here, along with the sound of them rustling through the grass! There were many times where we would be walking on a trail, I would stop, and say "there's a snake over here" and pull a snake out from the cover of grass! Its always made me wonder how members of indigenous tribes, that hunt and gather, perceive the world.
- munificent 4y ago> I would stop, and say "there's a snake over here" and pull a snake out from the cover of grass! Same! It's always weird when I know there's a snake there even before I have consciously recognized that I've seen it.
- aussiesnack 4y agoOur biggest animal dangers here are humans, horses, and cows. In that order.
- MichaelDickens 4y agoThis article talks about something called the "Sherwin-Williams Effect", but DuckDuckGo doesn't turn up any relevant results. Does anyone know what it is?
- kthejoker2 4y agoI think it's just an in joke about the Sherwin Williams paint company logo, which shows paint running down the Earth from the Northern Hemisphere. http://penguinology.blogspot.com/2011/01/fossil-hunt-in-antarctica.html?m=1 http://penguinology.blogspot.com/2011/01/fossil-hunt-in-anta...
- vouaobrasil 4y agoThere is strong evidence that a lot of bird evolution occurred in Gondwana as well. A good book for that is Tim Low's "Where Song Began".
- AlbertCory 4y agoAside from the truth or falsity of this theory: Why is it a matter of regional pride whether mammals (or humans) originated in your region? Usually there was no nation or culture there at the time, and in this case, not even any humans.
- zoklet-enjoyer 4y agoPeople are proud of all kinds of things that they have no control over/didn't do. Race, nation, sports teams, etc
- AlbertCory 4y agoMost of those date from the last 50,000 years, at the very latest.
- andrewflnr 4y agoThat's far enough back to be functionally indistinguishable from 50mya. The same level of personal choice is involved. And yet... People are always looking for a reason to be special, they'll take whatever they can get.
- AlbertCory 4y ago> functionally indistinguishable from 50mya not quite. In the former, there were homo sapiens while in the latter, not.
- andrewflnr 4y agoDo you think people take into account the timeline of homo sapiens in their region when they decide whether to have "regional pride"? I suspect not. You're looking for sense where there is none to be found.
- escapecharacter 4y agoI need to know when we start the Mammals vs Birds game in the World Cup who to cheer for
- Melatonic 4y agoThe megafauna of south america and north america are particularly fascinating - the big predators were all marsupials. Marsupial Saber Tooth Tigers.
- kuhewa 4y agoDefinitely not all. Thylacosmilus was, Smilodon was not nor was Homotherium.