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New Theory Suggests Dinosaurs Were Already Dying When Asteroid Hit (phys.org)
The new "biotic revenge hypothesis" suggests that dinosaurs were killed off by toxic plants. (And an inability to recognize the taste of a toxic plant.) the gmr summarizes a new paper reported at Phys.org:
The dinosaur population had been drastically decreasing before the asteroid impact, [and] the appearance of the first flowering plants -- angiosperms -- in the fossil record coincides with the gradual disappearance of the dinosaurs... The scientists concluded that though the asteroid played a role in the extinction of dinosaurs, the "plants had already placed severe strain on the species."
Crocodiles (believed to be descended from dinosaurs) also can't recognize the taste of toxic plants -- the researchers tested 10 different species. And they point out that not only did dinosaurs start to disappear before the asteroid impact -- they continued to "gradually disappear for millions of years afterward."
Crocodiles (believed to be descended from dinosaurs) also can't recognize the taste of toxic plants -- the researchers tested 10 different species. And they point out that not only did dinosaurs start to disappear before the asteroid impact -- they continued to "gradually disappear for millions of years afterward."
A quick quote from Wikipedia,
As such, birds were the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event 66 million years ago.
Crocodiles are not decedents of dinosaurs - they are reptiles. If this paper can not even see this then I can not put much weight into their theory.
I wonder if birds can taste the toxins then, since they're descended from dinosaurs and survived, though apparently at their worst they were down to a fairly small population on a remote island somewhere. (Can't remember where I read that...)
"I have never let my schooling interfere with my education." - Mark Twain
WOW! Someone made up more stupid RANDOM TRASH
Indeed. The paper is published by a psychologist, who is trying to psychoanalyse dinosaurs that lived 70 million years ago, when there is little evidence that psychoanalysis even works on living humans.
TFA contains some serious scientific illiteracy:
1. Dinosaurs are not "a species".
2. Crocodiles did not "descend from dinosaurs"
3. Plants would have no reason to evolve tasteless toxins, and there is no evidence whatsoever that they did.
Also, dinosaurs didn't go extinct. Some species died out, but other species survived. I have four small dinosaurs in my backyard, and they are very much alive. I keep them in my chicken coop, and their eggs are delicious. Much better than store-bought dinosaur eggs.
This may (although it doesn't, really) explain the decline of dinosaurs, but it says nothing about why thousands of other species (including all the ammonites) went extinct at the same time.
And the theory that dinosaurs were already dying off before the K/Pg boundary is hardly new. Part of that is an artifact of how fossils are formed and found. A species could have lasted several million years after its latest-known fossil, it just didn't happen to leave any fossils that have yet been found. (Conversely, the last surviving member of a species could have been fossilized. Unlikely though, except in the case of a mass extinction event.)
-- Alastair
And they point out that not only did dinosaurs start to disappear before the asteroid impact -- they continued to "gradually disappear for millions of years afterward."
If dinosaurs survived for millions of years after the asteroid impact, then very clearly the impact did not kill them. The asteroid didn't kill the dinosaurs any more than the Black Death killed humanity. No, Trump will kill humanity. Trump will kill us dead. Trump!
There's zero evidence that dinosaurs existed after the asteroid. The article referred to by Slashdot, the Biotic Revenge Hypotheses has this citation for their "continued to survive" claim:
Sakamoto, M., Benton, M.J., and C. Venditti. 2016. Dinosaurs in decline tens of millions of years before their final extinction. Proceedings of the National Academy of Sciences 113(18):5036–5040
But the Sakamoto article says this about that: "The fossil record shows that dinosaurs existed to the K-Pg boundary but did not survive into the Cenozoic"
So, bzzzzt wrong answer.
see here. Haven't you ever seen a dog eat grass?
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Anyone know if florists will deliver to Congress?
It must have been something you assimilated. . . .
First the Earth cooled. And then the dinosaurs came, but they got too big and fat, so they all died and they turned into oil. And then the Arabs came and they bought Mercedes Benzes. [McCroskey walks off] And Prince Charles started wearing all of Lady Di's clothes. I couldn't believe it- [Jacobs turns and starts to walk away, continuing to speak, trailing off as he gets further from the camera] he took her best summer dress and he put it on and went to town...
I'm guessing that the problem here is something called "the gmr." That's the first link in the Slashdot article. It looks to be a badly garbled summary of the paper which is accessible as a pdf from the second link.
I'm not going to waste time deconstructing the gmr material. It's kind of a shambles.
What the paper actually says if one tracks it down is that dinosaurs MAY have been in decline at the end of the Cretaceous -- true, but hardly proven. The sampling is so non-random that it's hard to tell. The paper itself seems to argue that caimans (a variety of crocodilian) don't reject a foodstuff just because it made them sick the last time they ate it. Birds OTOH, do. They then hypothesize that the dinosaurs might have been more like caimans than birds and that they poisoned themselves because, unlike, birds, they couldn't/didn''t avoid plants that made them sick.
That's not stupid, but if you ask me, it's rather a lot of conjecture based on a pretty limited factual foundation.
You can't see ANYTHING from a car, You've got to get out of the goddamned contraption and walk...Edward Abbey
Except there's this one. I had forgotten about it due to the thought that a single bone is more likely to be a re-buried bone, and also because I forget a lot of stuff lately. Decide for yourself.
http://palaeo-electronica.org/...
https://gsa.confex.com/gsa/201...
"There's zero evidence that dinosaurs existed after the asteroid"
Not zero. There's rather a lot of dinosaur material in early Paleocene strata in North America. The issue is whether it is (all) reworked from underlying cretaceous strata. In particular, a lot a folks think the saurian remains in the Ojo Alamo Formation in New Mexico are Paleocene . However, to my knowledge, no one has yet found an articulated Paleocene dinosaur skeleton. If articulated material is ever found, that'll probably settle the argument.
You can't see ANYTHING from a car, You've got to get out of the goddamned contraption and walk...Edward Abbey
Well, that's one of the most entertainingly batshit ideas I've heard this week. Thanks!
SJW n. One who posts facts.
I missed something when reading that ... how would an electrical discharge alter the Earth's gravity?
First time I've heard anybody claim crocodiles are dinosaurs.
Because they are not. Dinosaurs and crocodiles are both archosaurs. But to claim one group is descended from the other is incorrect in much the same way as I am not descended from my brother.
Crocodiles are also not lizards. Lizards split with archosaurs before dinosaurs and crocodiles split. So crocodiles are not lizards in the same way as I am not descended from my cousin.
All I want is a secure system where it's easy to do anything I want. Is that too much to ask ~~ Randall Munroe
Random mutations happen, some stick around, and a new equilibrium is established.
Toxins require energy to produce, and often are stressful for the plant, since they are ... toxic. So the genes for them aren't going to "stick around" unless they provide some countervailing benefit. If they are tasteless, they will not prevent consumption by herbivores, and will have no adaptive benefit.
It is possible that the toxin was directed at a different predator, such as insects, and just killed the dinosaurs as collateral damage. But that is just conjecture. There is no evidence that such toxins existed.
The very first answer in the first link you posted answers the question:
<quote>Dinosaurs do not violate the square cube law.
Take the known strengths of bone and muscle, assume an animal shaped like the largest dinosaurs, apply the square cube law, and you get the maximum possible size and mass for an animal of that shape.
And, wait for it...
It turns out that maximum possible size and mass is just a tiny bit BIGGER than the biggest known dinosaurs!</quote>
Dinosaurs are a different shape to mammals.
The herbivore won't be back to eat the plants siblings, who share a lot of the same genes.
https://en.wikipedia.org/wiki/Inverted_totalitarianism
This includes 1.5 tonne monstrosities like Yutyrannus Huali, (related to Tyranosaurous Rex) https://news.nationalgeographi...
Discoveries and detailed analysis of recent dinosaur fossils indicate that they were covered with feathers long before flight evolved. And they are now believed to have been warm-blooded. this is confirmed by CT scans of well-preserved fossils (e.g. 600 pound herbivore) showing a 4-chambered heart with *ONE* aorta http://contenidopatrocinado.cn... This is a physiological sign of a warm blooded animal.
So dinosaurs had feathers and were warm blooded. Birds have feathers and are warm blooded. Birds are one group of dinosaurs that survived the asteroid. This was probably due to small size and being able to scavenge scarce food right after the impact.
I'm not repeating myself
I'm an X window user; I'm an ex-Windows user
Airplanes are not bound by Galileo's square-cube law.
What I notice about the Quora claim is that the person did not include their algebra. He is making a claim about algebra, but fails to go through the math.
By contrast, others have indeed gone through the math, like here in the 2nd and 3rd bubbles and the answer of ~21,000 lbs would seem to be very far shy of the largest dinosaur weights. It seems very unlikely that fiddling with bone and muscle densities (etc) is going to make up the difference to the 176,000 pounds that the sauropod is claimed to have weighed.
The weight of the largest land-walking dinosaurs is a paradox.
The largest flying creatures from these times are also a paradox. 8 meters was thought to be the theoretical wingspan limit for any airborne creature -- at least until Quetzalcoatlus specimens were found.
What we see in these scientific disciplines are theorists fiddling with the numbers and behaviors in order to satisfy the paradox that they cannot exist in our current gravity. For instance, it has been claimed that the Pteranodon did not actually fly -- but rather could only glide. Yet, in some cases, the remains of these creatures are found with fish fossils and the bird had a throat pouch like a pelican. So, the creature goes down to scoop up some fish, and then what? How does it get back up to its nest? It doesn't seem that people think much about these problems these days.
Regardless, the largest flying creatures were a paradox.
Then, there are the problematic necks of the largest-necked creatures. Giraffes require an extraordinary blood pressure to get blood to their necks 20 feet up. But, the sauropod had a neck of about 50-60 feet in length! This raises issues related to not just blood pressure, but also torque.
Do the math on this blood pressure and torque, and the largest-necked creatures were a paradox.
Theorists will typically try to address just one of these problems at a time (by suggesting that the sauropod did not elevate its neck, reducing bone density or proposing that the air must have been thicker, for example), but it would seem that the only way to resolve all three problems at once is to alter gravity, no?
Indeed. Crocodilians are the closest living relatives to dinosaurs that are not themselves dinosaurs (the closest living relatives are, of course, the avian dinosaurs that are still around - a particularly cute variety of which is is currently trying to preen my fingers while I type ;) )
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