Neil said in a topic a while back that an African Lion would stand no chance against one of the big Theropod carnivores.
This got me thinking; are mammals really all we kind of naturally assume we are? For the sake of argument, let's remove our own freakish species from the equation, and instead of Dinosaurs, let's talk about Archosaurs (including Pterosaurs and Crocodiles and things close to Crocodiles), and maybe even diapsid reptiles in general (which includes lizards and all non-turtle reptiles).
Now, the dinosaurs got a lot bigger, and it is probably fair to say that the greatest Dinosaur carnivore (say, Spinosaurus or T-Rex) would pretty easily make a lunch out of Andrewsarchus. But I think the more interesting comparison is between the greatest Dinosaur predator and the greatest Mammal herbivore, which would probably be either the Giant Sloth, Indricotherium or the greatest of the Mammoths. I don't see the T-Rex winning without a hell of a fight.
The more interesting argument is more general though.
Mammals-Advantages:
Relatively large brain
Better sense of hearing
I think better heat management, but probably not totally fair
Specialized teeth
We chew
I think live birth is generally preferable
TITTIES!
Arguably more adaptable
Disadvantages:
Huge heads
Wasteful waste process
4 legs (?)
Archosaurs-Advantages:
Much more efficient breathing
Much more efficient waste
Lighter skull, I think generally a lighter frame, I don't know if mammals have the same type of air sacs
Two-legs
Disadvantages:
Generally speaking, smaller brains
So, let's say I were to introduce a bunch of foxes, rabbits, deer, rats and chimps in to a mid Cretaceous forest. What happens? Does the age of Mammals come a lot sooner, or would they be totally out of their class even if we put them in a comparable environment with sufficient numbers? Were archosaurs simply *better* at doing their things back then than we are now? The dinosaurs definetely kicked our Therapsid ancestor's butts during the Triassic, but then again we gave the big Birds (basically retconned dinosaurs) a good clobbering at the end of the Eocene, and during the Great American Interchange the big cats pretty rapidly took over top predator position from the big South American birds, though IIRC the big birds were one of the few species to travel north.
Damn good question Squeelus.
Mutton is physical incapable of sarcasm.
Quote from: Queequeg on January 02, 2010, 11:57:03 PM
Neil said in a topic a while back that an African Lion would stand no chance against one of the big Theropod carnivores.
This got me thinking; are mammals really all we kind of naturally assume we are? For the sake of argument, let's remove our own freakish species from the equation, and instead of Dinosaurs, let's talk about Archosaurs (including Pterosaurs and Crocodiles and things close to Crocodiles), and maybe even diapsid reptiles in general (which includes lizards and all non-turtle reptiles).
Now, the dinosaurs got a lot bigger, and it is probably fair to say that the greatest Dinosaur carnivore (say, Spinosaurus or T-Rex) would pretty easily make a lunch out of Andrewsarchus. But I think the more interesting comparison is between the greatest Dinosaur predator and the greatest Mammal herbivore, which would probably be either the Giant Sloth, Indricotherium or the greatest of the Mammoths. I don't see the T-Rex winning without a hell of a fight.
The more interesting argument is more general though.
Mammals-Advantages:
Relatively large brain
Better sense of hearing
I think better heat management, but probably not totally fair
Specialized teeth
We chew
I think live birth is generally preferable
TITTIES!
Arguably more adaptable
Disadvantages:
Huge heads
Wasteful waste process
4 legs (?)
Archosaurs-Advantages:
Much more efficient breathing
Much more efficient waste
Lighter skull, I think generally a lighter frame, I don't know if mammals have the same type of air sacs
Two-legs
Disadvantages:
Generally speaking, smaller brains
So, let's say I were to introduce a bunch of foxes, rabbits, deer, rats and chimps in to a mid Cretaceous forest. What happens? Does the age of Mammals come a lot sooner, or would they be totally out of their class even if we put them in a comparable environment with sufficient numbers? Were archosaurs simply *better* at doing their things back then than we are now? The dinosaurs definetely kicked our Therapsid ancestor's butts during the Triassic, but then again we gave the big Birds (basically retconned dinosaurs) a good clobbering at the end of the Eocene, and during the Great American Interchange the big cats pretty rapidly took over top predator position from the big South American birds, though IIRC the big birds were one of the few species to travel north.
(https://languish.org/forums/proxy.php?request=http%3A%2F%2Fimg340.imageshack.us%2Fimg340%2F4479%2Fjohnstewartfacepalm.gif&hash=95a315ace7745288843ebeb7986a0f8044f99004)
Edit: Turns out that the oxygen content of the atmosphere was lower in the Mesozoic. With that in mind, I think that modern mammals would have serious issues competing until they adapted, assuming they survived that long.
Dinosaurs vs Mammals? Sounds like something you'd find on the History Channel
I've seen this porno.
I saw this in King Kong...
But you are comparing animals separated by 50 million years in time. But if you want to compare like with like.
Indricotherum K-T + 37M to 51M years.
Compare that with hunters 37M years into the Jurassic 162M years ago.
Indricotherum ~ 10,000 kg - 20,000 kg
Andrewsarchus ~700 kg - 1,000 kg
Brachiosaurus ~ 25,000 kg
Allosaurus ~ 1,400 kg - 2,000 kg
Didn't mammals survive in real history at the time of the dinosaurs by being little rodent/rabbity things?
I'd think our modern swarm creatures would do very well assuming they can eat the food and breath the air (handwavium ftw).
In the colder regions I'd imagine mammals do a lot better too....not that there was much in the way of 'cold' regions back then.
http://www.bobheffner.com/dinosaursattack/indexfront.htm (http://www.bobheffner.com/dinosaursattack/indexfront.htm)
Remember the old Dinosaurs Attack cards. There is a few when the dinosaurs attack a zoo. See the mighty Pterodactyl attacking a gorilla.
Witness the tricerotops raid a wedding.
And come face to face with the Ultimate Evil who engineered the whole thing.
Dun dun DUUUUUUUUUN.
Quote from: Tyr on January 03, 2010, 08:24:34 AM
Didn't mammals survive in real history at the time of the dinosaurs by being little rodent/rabbity things?
I'd think our modern swarm creatures would do very well assuming they can eat the food and breath the air (handwavium ftw).
In the colder regions I'd imagine mammals do a lot better too....not that there was much in the way of 'cold' regions back then.
Don't forget that the mammal like reptiles dominated the world before the Jurassic.
Quote from: Darth Wagtaros on January 03, 2010, 08:31:56 AM
http://www.bobheffner.com/dinosaursattack/indexfront.htm (http://www.bobheffner.com/dinosaursattack/indexfront.htm)
Remember the old Dinosaurs Attack cards. There is a few when the dinosaurs attack a zoo. See the mighty Pterodactyl attacking a gorilla.
Witness the tricerotops raid a wedding.
And come face to face with the Ultimate Evil who engineered the whole thing.
Dun dun DUUUUUUUUUN.
Love the kid strikes back one, lol.
Quote from: Syt on January 03, 2010, 01:37:16 AM
(https://languish.org/forums/proxy.php?request=http%3A%2F%2Fimg340.imageshack.us%2Fimg340%2F4479%2Fjohnstewartfacepalm.gif&hash=95a315ace7745288843ebeb7986a0f8044f99004)
Normally I despise Jon Stewart, but this covers my reaction as well.
Quote from: Queequeg on January 02, 2010, 11:57:03 PM
Archosaurs-Advantages:
Much more efficient breathing
This is precisely the opposite of what I recall from my bio classes. Mammals, as I recall, are something like 10 times as efficient at breathing as reptiles.
Edit: http://books.google.com/books?id=p7rRLryz2cgC&pg=PA145&lpg=PA145&dq=reptile+%22breathing+efficiency%22&source=bl&ots=_Wa8_ubCon&sig=FCRE6JGRsljAOMW0PLkkuSbxJGk&hl=en&ei=4qpAS-mxHsfRlAfU6eCjBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBIQ6AEwAg#v=onepage&q=&f=false (http://books.google.com/books?id=p7rRLryz2cgC&pg=PA145&lpg=PA145&dq=reptile+%22breathing+efficiency%22&source=bl&ots=_Wa8_ubCon&sig=FCRE6JGRsljAOMW0PLkkuSbxJGk&hl=en&ei=4qpAS-mxHsfRlAfU6eCjBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBIQ6AEwAg#v=onepage&q=&f=false)
seems to bear this out: "...the relative cost of ventilation for all three classes of lower vertebrates is an order of magnitude greater for all three species of lower vertebrate compared to the mammals."
You're biased.
I would imagine that deer would get eaten in relatively short order, although that would depend on their ability to maintain their high activity levels. The other, smaller animals would essentially be occupying the sort of niches that mammals were already in around that time. By the late Cretaceous, the changes in the biosphere had forced the dinosaurs out of the small end of the scale. They'd be competing with their own ancestors, not with dinosaurs.
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
Quote from: grumbler on January 03, 2010, 09:41:53 AM
Quote from: Queequeg on January 02, 2010, 11:57:03 PM
Archosaurs-Advantages:
Much more efficient breathing
This is precisely the opposite of what I recall from my bio classes. Mammals, as I recall, are something like 10 times as efficient at breathing as reptiles.
Edit: http://books.google.com/books?id=p7rRLryz2cgC&pg=PA145&lpg=PA145&dq=reptile+%22breathing+efficiency%22&source=bl&ots=_Wa8_ubCon&sig=FCRE6JGRsljAOMW0PLkkuSbxJGk&hl=en&ei=4qpAS-mxHsfRlAfU6eCjBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBIQ6AEwAg#v=onepage&q=&f=false (http://books.google.com/books?id=p7rRLryz2cgC&pg=PA145&lpg=PA145&dq=reptile+%22breathing+efficiency%22&source=bl&ots=_Wa8_ubCon&sig=FCRE6JGRsljAOMW0PLkkuSbxJGk&hl=en&ei=4qpAS-mxHsfRlAfU6eCjBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBIQ6AEwAg#v=onepage&q=&f=false)
seems to bear this out: "...the relative cost of ventilation for all three classes of lower vertebrates is an order of magnitude greater for all three species of lower vertebrate compared to the mammals."
There's something of a debate on that. Older sources take it for granted that dinosaurs are essentially scaled up lizards, whereas these days it's popular to assign them features more similar to birds. Clearly, the dinosaurs could not have been the same as reptiles, because otherwise the Jurassic atmosphere would have required oxygen levels of around 40% to support observed activity levels on large sauropods. At levels like that, the biosphere would spontaneously combust. The question is, how bird-or-mammal-like were they?
Actually, I own a boardgame about this, which no one wants to play.
Quote from: Tamas on January 03, 2010, 09:57:45 AM
Actually, I own a boardgame about this, which no one wants to play.
You smell like cabbage.
Quote from: grumbler on January 03, 2010, 09:41:53 AM
Quote from: Queequeg on January 02, 2010, 11:57:03 PM
Archosaurs-Advantages:
Much more efficient breathing
This is precisely the opposite of what I recall from my bio classes. Mammals, as I recall, are something like 10 times as efficient at breathing as reptiles.
Edit: http://books.google.com/books?id=p7rRLryz2cgC&pg=PA145&lpg=PA145&dq=reptile+%22breathing+efficiency%22&source=bl&ots=_Wa8_ubCon&sig=FCRE6JGRsljAOMW0PLkkuSbxJGk&hl=en&ei=4qpAS-mxHsfRlAfU6eCjBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBIQ6AEwAg#v=onepage&q=&f=false (http://books.google.com/books?id=p7rRLryz2cgC&pg=PA145&lpg=PA145&dq=reptile+%22breathing+efficiency%22&source=bl&ots=_Wa8_ubCon&sig=FCRE6JGRsljAOMW0PLkkuSbxJGk&hl=en&ei=4qpAS-mxHsfRlAfU6eCjBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBIQ6AEwAg#v=onepage&q=&f=false)
seems to bear this out: "...the relative cost of ventilation for all three classes of lower vertebrates is an order of magnitude greater for all three species of lower vertebrate compared to the mammals."
I could be mistaken, but if I recall correctly, dinosaur's breathing was as efficient as birds, which is more efficent than mammals.
(https://languish.org/forums/proxy.php?request=http%3A%2F%2Fwww.ottens.co.uk%2Fgatehouse%2Fimages%2Fcolonial%2Fhunter%2520by%2520Dr%2520Grordbort.jpg&hash=a9cfe8038e63da83b2c5b7c5a811d688ee28f5d6)
Mammals vs Dinosaurs
Quote from: jimmy olsen on January 03, 2010, 10:05:10 AM
I could be mistaken, but if I recall correctly, dinosaur's breathing was as efficient as birds, which is more efficent than mammals.
The flying dinosaurs had air sacs in their bones, which gave them great efficiency at the cost of great fragility. I doubt that this was true of the larger saurians.
In any case, we are talking archosaurs here, and only aviary species appear to have evolved the efficient-but-fragile breathing system. Crocodiles certainly don't have it, and they are archosaurs as well.
Quote from: grumbler on January 03, 2010, 10:26:42 AM
Quote from: jimmy olsen on January 03, 2010, 10:05:10 AM
I could be mistaken, but if I recall correctly, dinosaur's breathing was as efficient as birds, which is more efficent than mammals.
The flying dinosaurs had air sacs in their bones, which gave them great efficiency at the cost of great fragility. I doubt that this was true of the larger saurians.
In any case, we are talking archosaurs here, and only aviary species appear to have evolved the efficient-but-fragile breathing system. Crocodiles certainly don't have it, and they are archosaurs as well.
It seems that Theropods at least breathed like birds.
Not a great article, though, I'll look for a better one.
http://www.livescience.com/animals/050713_dino_bird.html
QuoteDinosaurs Breathed Like Birds
By Robert Roy Britt, LiveScience Senior Writer
posted: 13 July 2005 01:04 pm ET
Birds evolved from dinosaurs, most paleontologists agree. But there are big questions about just how similar the large dinosaurs really were to today's eagles and hawks.
Experts still argue whether dinosaurs were hot-blooded, agile and active like the cunning predators in "Jurassic Park" or, as scientists at U.C. Berkeley phrase the old conventional view, "sluggish and stupid."
A new study finds an important bird trait embedded in dinosaur bones that argues for the more nimble view.
Big meat-eating dinosaurs had a complex system of air sacs similar to the setup in today's birds, according to an investigation led by Patrick O'Connor of Ohio University. The lungs of theropod dinosaurs -- carnivores that walked on two legs and had bird-like feet -- likely pumped air into hollow sacs in their skeletons, as is the case in birds.
"What was once formally considered unique to birds was present in some form in the ancestors of birds," O'Connor said.
The study, funded in part by the National Science Foundation, is detailed in the July 14 issue of the journal Nature.
Theory takes flight
For more than three decades, scientists have seriously pondered the idea that birds are today's dinosaurs. The theory was put on solid footing in 1996 with the discovery of a well preserved, small and feathered dinosaur named sinosauropterx.
Other studies have since suggested that while an adult T. rex likely had scales, its young may have been covered in downy feathers.
Yet paleontologists had long thought that dinosaurs were cold-blooded, like reptiles. A reptile's simple heart puts only low amounts of oxygen in its blood -- not the right mix in the recipe of flight.
Modern computerized tomography (CT) scans of dinosaur chest cavities five years ago found the apparent remnants of complex, four-chambered hearts more like mammals and birds.
Earlier this year, rare soft tissue of a T. rex showed its blood vessels were similar to those of an ostrich.
Meanwhile, sketchy evidence in recent years had suggested dinosaur bones might contain air cavities. Still, some experts contended dinosaurs breathed more like crocodiles.
In the new study, O'Connor and his colleague, Leon Claessens of Harvard University, examined Majungatholus atopus, a recently discovered primitive theropod that is several yards long. They found cavities in its vertebral bones similar to those found in birds.
They found that "the pulmonary system of meat-eating dinosaurs such as T. rex in fact shares many structural similarities with that of modern birds," Claessens said.
Warm or cold?
A bird's air sacs are distributed throughout its body. The lungs never change shape, Claessens explained. Instead, fresh air is constantly being drawn from the air sacs through the lungs, in both directions, creating a very efficient respiration system.
There is also evidence that the dinosaur's rib cage was adapted for this type of system, Claessens told LiveScience.
The superior breathing apparatus, along with their complex hearts, increases bird metabolism and makes them warm-blooded, meaning they generate internal heat that controls their body temperature.
Reptiles are cold-blooded, relying on the environment and their behavior to regulate body temperature.
Though the dinosaur breathing system was not likely identical to living birds, "it's nothing like the crocodile system as we know it," O'Connor said.
The newfound similarities do not necessarily mean dinosaurs were warm-blooded, however. While that debate continues, O'Connor speculates that the blood of the long-gone beasts was probably somewhere between warm and cold.
These articles seem better.
http://www.bioedonline.org/news/news.cfm?art=680
http://www.ns.umich.edu/htdocs/releases/story.php?id=6758
Interesting. I would have thought these kinds of dinosaurs would have suffered more from the fragility/brittleness of the bones than gained from the forced-pump breathing system, but obviously not.
However, this doesn't say that all dinos had this system. OTOH, every one whose heart shapes have been fossilized appear to have had four-chamber hearts, so maybe they all had the breathing system as well.
In any case, i withdraw my objection; my info was out of date, it seems.
Quote from: Viking on January 03, 2010, 08:32:51 AM
Quote from: Tyr on January 03, 2010, 08:24:34 AM
Didn't mammals survive in real history at the time of the dinosaurs by being little rodent/rabbity things?
I'd think our modern swarm creatures would do very well assuming they can eat the food and breath the air (handwavium ftw).
In the colder regions I'd imagine mammals do a lot better too....not that there was much in the way of 'cold' regions back then.
Don't forget that the mammal like reptiles dominated the world before the Jurassic.
I'm not old enough to remember that.
Quote from: Ed Anger on January 03, 2010, 09:56:01 AM
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
OH
FUCK
YEAH!!!! KEEEP GOIN!
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
Quote from: dps on January 03, 2010, 01:54:55 PM
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
How would that solve anything?
Quote from: Darth Wagtaros on January 03, 2010, 01:35:50 PM
Quote from: Ed Anger on January 03, 2010, 09:56:01 AM
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
OH FUCK
YEAH!!!! KEEEP GOIN!
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
Quote from: Neil on January 03, 2010, 02:24:40 PM
Quote from: dps on January 03, 2010, 01:54:55 PM
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
How would that solve anything?
We could televise it and sell it on Pay-per-view.
$$
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
Speaking of free-market insanity, I found a magazine called 'Newsmax' in my lobby this morning.
Quote from: Ed Anger on January 03, 2010, 02:28:42 PM
Quote from: Neil on January 03, 2010, 02:24:40 PM
Quote from: dps on January 03, 2010, 01:54:55 PM
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
How would that solve anything?
We could televise it and sell it on Pay-per-view.
$$
I rather doubt that'd be legal.
Quote from: Neil on January 03, 2010, 02:31:37 PM
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
Speaking of free-market insanity, I found a magazine called 'Newsmax' in my lobby this morning.
:lol:
Free copy of palin's book with subscription.
Quote from: Neil on January 03, 2010, 02:32:16 PM
Quote from: Ed Anger on January 03, 2010, 02:28:42 PM
Quote from: Neil on January 03, 2010, 02:24:40 PM
Quote from: dps on January 03, 2010, 01:54:55 PM
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
How would that solve anything?
We could televise it and sell it on Pay-per-view.
$$
I rather doubt that'd be legal.
In a perfect world, feeding Spellus to animals would be.
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
Quote from: Darth Wagtaros on January 03, 2010, 01:35:50 PM
Quote from: Ed Anger on January 03, 2010, 09:56:01 AM
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
OH FUCK
YEAH!!!! KEEEP GOIN!
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
You must be one of those fanfiction writers they hire on to do filler.
Quote from: Darth Wagtaros on January 03, 2010, 02:40:18 PM
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
Quote from: Darth Wagtaros on January 03, 2010, 01:35:50 PM
Quote from: Ed Anger on January 03, 2010, 09:56:01 AM
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
OH FUCK
YEAH!!!! KEEEP GOIN!
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
You must be one of those fanfiction writers they hire on to do filler.
I'm Tom Kratman.
Quote from: Ed Anger on January 03, 2010, 02:36:59 PM
Quote from: Neil on January 03, 2010, 02:31:37 PM
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
Speaking of free-market insanity, I found a magazine called 'Newsmax' in my lobby this morning.
:lol:
Free copy of palin's book with subscription.
They recommend that I invest in gold.
Quote from: Ed Anger on January 03, 2010, 02:42:33 PM
Quote from: Darth Wagtaros on January 03, 2010, 02:40:18 PM
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
Quote from: Darth Wagtaros on January 03, 2010, 01:35:50 PM
Quote from: Ed Anger on January 03, 2010, 09:56:01 AM
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
OH FUCK
YEAH!!!! KEEEP GOIN!
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
You must be one of those fanfiction writers they hire on to do filler.
I'm Tom Kratman.
He ruined the Legacy of the Aldenata series with his inane SS fanboism. :(
Quote from: Darth Wagtaros on January 03, 2010, 03:08:06 PM
Quote from: Ed Anger on January 03, 2010, 02:42:33 PM
Quote from: Darth Wagtaros on January 03, 2010, 02:40:18 PM
Quote from: Ed Anger on January 03, 2010, 02:27:56 PM
Quote from: Darth Wagtaros on January 03, 2010, 01:35:50 PM
Quote from: Ed Anger on January 03, 2010, 09:56:01 AM
Then the Count Belisarius comes through a rip in the space time continuum, kills all the dinosaurs, forms an alliance with Neanderthals and conquers the world with his Neo-roman greek speaking empire.
bork! bork! bork!
OH FUCK
YEAH!!!! KEEEP GOIN!
I'll fire up the Baen book generator. The cro-magnons must be crushed because their socialist form of economy is abhorrent and is offensive to the author.
You must be one of those fanfiction writers they hire on to do filler.
I'm Tom Kratman.
He ruined the Legacy of the Aldenata series with his inane SS fanboism. :(
It was so bad it was good.
Quote from: Neil on January 03, 2010, 02:24:40 PM
Quote from: dps on January 03, 2010, 01:54:55 PM
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
How would that solve anything?
Prevent future threads like this?
Quote from: Razgovory on January 03, 2010, 08:28:20 PM
Quote from: Neil on January 03, 2010, 02:24:40 PM
Quote from: dps on January 03, 2010, 01:54:55 PM
I suggest that we conduct an experiment on this issue by throwing Spellus to the crocodiles.
How would that solve anything?
Prevent future threads like this?
I'm interested in threads like this. Natural history is fascinating.
What part of natural history is Dinosaurs vs mammals?
Quote from: Razgovory on January 03, 2010, 08:33:58 PM
What part of natural history is Dinosaurs vs mammals?
Both dinosaurs and mammals are components of Earth's rich natural history.
Quote from: grumbler on January 03, 2010, 12:13:22 PM
Interesting. I would have thought these kinds of dinosaurs would have suffered more from the fragility/brittleness of the bones than gained from the forced-pump breathing system, but obviously not.
However, this doesn't say that all dinos had this system. OTOH, every one whose heart shapes have been fossilized appear to have had four-chamber hearts, so maybe they all had the breathing system as well.
In any case, i withdraw my objection; my info was out of date, it seems.
One of the arguments that dinosaurs had bird like respitory systems is the long necks many of the larger ones had. The problem being that mammalian respitory systems have limits on neck length because when we inhale the first air to enter our lungs is the air in the trachea that we have already used (the longer the neck-->the longer the trachea-->the higher the percentage of used air in our lungs). There was a group that analyzed this a few years ago and came to the conclusion that sauropods never could have been so large with a mammalian respitory system (and a reptilian would have been even worse) and it seems likely they had an avian system.
If sauropods had that type of breathing system, it would be good evidence that it was common if not universal in dinosaurs, as birds actually evolved from the theropods.
Although the sauropods were actually more closely related to the theropods than they were any other group of dinosaurs.
Do giraffes have problems with respiratory stress?
Quote from: Neil on January 03, 2010, 09:10:23 PM
Although the sauropods were actually more closely related to the theropods than they were any other group of dinosaurs.
There are two orders of dinosaurs, and theropods and sauropods are in one. What is interesting is that their group was named for lizards, and the other was named for birds, as early on a relationship with birds was noticed in the other group. However, birds actually came from the order with the lizard name.
Quote
Do giraffes have problems with respiratory stress?
Obviously they work out okay, but they are much smaller than the larger dinosaurs.
That would help to explain why even the big mammals, like the Indricothere, didn't have the same kind of long necks as the Sauropods.
Interestingly, do we know when/why Dinosaurs developed such a massively superior breathing apparatus? Clearly lizards don't, and I don't think Crocodiles do either, and it seems like a fair guess that Pterosaurs didn't, making that a probable advantage birds had.
Quote from: Queequeg on January 03, 2010, 09:36:34 PM
That would help to explain why even the big mammals, like the Indricothere, didn't have the same kind of long necks as the Sauropods.
Interestingly, do we know when/why Dinosaurs developed such a massively superior breathing apparatus? Clearly lizards don't, and I don't think Crocodiles do either, and it seems like a fair guess that Pterosaurs didn't, making that a probable advantage birds had.
There are three basic respitory systems for breathing air (ignoring those of amphibians and some fish): reptilian, mammalian, and avian. The most efficient (in terms of extracting oxygen from inhaled air) is the avian, and the least is reptilian. The avian system isn't necessarily ideal, though, because it requires the most space within the body (and the mammalian requires more than the reptilian).
I don't know why you would guess that pterosaurs wouldn't have an avian system. It seems more and more likely that an avian system was present in most dinosaurs, and an avian system tends to be both more efficient and lighter (which is important for flight). Although bats show flight is possible with a mammalian system, they are smaller than the larger pterasaurs and I don't know of any diapsids that have a mammalian system (which doesn't mean there aren't any). I don't know of anything that flies with a reptilian system.
Still doesn't really answer my original question. How did the Avian-Dinosaur system come about? Crocodiles, Pterosaurs and Dinosaurs aren't that that distant of relations; I'd think that modern crocodiles would at least have some remnants of the prototype avian respiratory system.
Quote from: Queequeg on January 03, 2010, 10:03:41 PM
Still doesn't really answer my original question. How did the Avian-Dinosaur system come about? Crocodiles, Pterosaurs and Dinosaurs aren't that that distant of relations; I'd think that modern crocodiles would at least have some remnants of the prototype avian respiratory system.
There was a much lower amount of oxygen in the mesozoic period, so a more efficient breathing mechanism was selected for.
Quote from: Queequeg on January 03, 2010, 10:03:41 PM
Still doesn't really answer my original question. How did the Avian-Dinosaur system come about? Crocodiles, Pterosaurs and Dinosaurs aren't that that distant of relations; I'd think that modern crocodiles would at least have some remnants of the prototype avian respiratory system.
Two comments: first, we don't really know what aspects of a respiratory system any long extinct animal had. Respiratory systems consist of soft tissue that isn't preserved, so we have to make a lot of guesses. Some dinosaurs show evidence of avian like structures, and physiologically we think that other extant systems wouldn't work for some of them, so we guess that these had an avian like system. But ~200 million years of evolution separate the sauropods from the systems we see today.
Second, it is possible that the prototype avian respiratory system emerged after the divergence of crocodiles and dinosaurs/pterosaurs.
Quote from: Razgovory on January 03, 2010, 08:33:58 PM
What part of natural history is Dinosaurs vs mammals?
I was wrong, it was on the Science Channel, not History
http://www.youtube.com/watch?v=YIKlplx11n4
Quote from: alfred russel on January 03, 2010, 09:29:22 PM
There are two orders of dinosaurs, and theropods and sauropods are in one. What is interesting is that their group was named for lizards, and the other was named for birds, as early on a relationship with birds was noticed in the other group. However, birds actually came from the order with the lizard name.
Yeah. At some point, the pubic boot turned itself back.
QuoteObviously they work out okay, but they are much smaller than the larger dinosaurs.
Their necks are terribly long though. I wonder what the upper limit is.
Quote from: alfred russel on January 03, 2010, 10:13:07 PM
Two comments: first, we don't really know what aspects of a respiratory system any long extinct animal had. Respiratory systems consist of soft tissue that isn't preserved, so we have to make a lot of guesses. Some dinosaurs show evidence of avian like structures, and physiologically we think that other extant systems wouldn't work for some of them, so we guess that these had an avian like system. But ~200 million years of evolution separate the sauropods from the systems we see today.
Second, it is possible that the prototype avian respiratory system emerged after the divergence of crocodiles and dinosaurs/pterosaurs.
However, paleontologist have made found soft tissue remains in the last ten years that have lead to great breakthroughs.
Quote
T. Rex Soft Tissue Found Preserved
Hillary Mayell
for National Geographic News
March 24, 2005
A Tyrannosaurus rex fossil has yielded what appear to be the only preserved soft tissues ever recovered from a dinosaur. Taken from a 70-million-year-old thighbone, the structures look like the blood vessels, cells, and proteins involved in bone formation.
Most fossils preserve an organism's hard tissues, such as shell or bone. Finding preserved soft tissue is unheard of in a dinosaur-age specimen.
"To my knowledge, preservation to this extent—where you still have original flexibility and transparency—has not been noted in dinosaurs before, so we're pretty excited by the find," said Mary H. Schweitzer, a paleontologist at North Carolina State University in Raleigh.
The findings may provide new insights into dinosaur evolution, physiology, and biochemistry. They could also increase our understanding of extinct life and change how scientists think about the fossilization process.
"Finding these tissues in dinosaurs changes the way we think about fossilization, because our theories of how fossils are preserved don't allow for this [soft-tissue preservation]," Schweitzer said.
Uncovering T. Rex
For three years scientists from the Museum of the Rockies in Bozeman, Montana, excavated the T. rex from sandstone at the base of the nearby Hell Creek formation. The dinosaur was relatively small and around 18 years old when it died.
"The dinosaur was under an incredible amount of rock," said Jack Horner, a curator of paleontology at the museum. "When it was collected, the specimen was very far away from a road, and everything had to be done by helicopter.
"The team made a plaster jacket to get part of the fossil out, and it was too big for the helicopter to lift. And so we had to take the fossil apart.
"In so doing, we had to break a thighbone in two pieces. When we did that, it allowed [Schweitzer] to get samples out of the middle of the specimen. You don't see that in most excavations, because every effort is made to keep the fossil intact," said Horner, a co-author of the study.
A certain amount of serendipity lead to the discovery.
Because the leg bone was deliberately broken in the field, no preservatives were added. As a result, the soft tissues were not contaminated.
The museum, which is a part of Montana State University, has a laboratory that specializes in cellular and molecular paleontology (the study of prehistoric life through fossil remains).
The study authors also looked at several other dinosaur fossils to see whether there was something unique about this particular T. rex fossil.
"There's nothing unique about the specimen other than the fact that it's the first that's been examined really well," Horner concluded. Other dinosaurs, in other words, are probably similarly preserved.
Soft Tissues
Schweitzer's background is in biology, and she performed a number of tests on the fossils that are common medical practices today.
The paleontologist and her colleagues removed mineral fragments from the interior of the femur by soaking it in a weak acid. The fossil dissolved, exposing a flexible, stretchy material and transparent vessels.
The vessels resemble blood vessels, cells, and the protein matrix that bodies generate when bones are being formed.
"Bone is living tissue, is very active tissue, and has its own metabolism and has to have a very good blood supply," Schweitzer said.
"So bone is infiltrated with lots and lots of blood vessels in its basic structure. When bone is formed, it's formed by cells that are specific for bone, that secrete proteins like collagen and form a matrix."
Further chemical analysis might enable the scientists to answer long-standing questions about the physiology of dinosaurs. For instance, were they warm-blooded, cold-blooded, or somewhere in between?
If protein sequences can be identified, they can be compared to those of living animals. This might allow a better understanding of how different groups of animals are related.
The find may potentially change field practices, perhaps by encouraging more scientists to reserve parts of fossils for cellular and molecular testing.
And once tested, the proteins definitely seem similar to avian proteins.
http://news.nationalgeographic.com/news/2007/04/070412-dino-tissues.html
Quote
Dinosaur Soft Tissue Sequenced; Similar to Chicken Proteins
Scott Norris
for National Geographic News
April 12, 2007
Ancient collagen—the main protein component of bone—has been extracted from the remains of a 68-million-year-old Tyrannosaurus rex, according to two new reports.
The new studies provide strong support for the hotly debated claims that organic material previously extracted from the T. rex's leg bone is original dinosaur soft tissue that somehow escaped fossilization.
Now, for the first time, scientists have obtained partial protein sequences from the soft tissue remains.
"The sequences are clearly from T. rex," said John Asara of Harvard Medical School in Cambridge, Massachusetts, who led one of the studies.
In addition, both studies found similarities between the dino sample and the bone collagen of chickens, providing molecular support for the hypothesis that modern birds are descended from dinosaurs.
Until now the dino-bird connection has been entirely based on physical similarities in fossils' body structures (related: "Earliest Bird Had Feet Like Dinosaur, Fossil Shows" [December 1, 2005]).
In a related study, a team led by Mary Higby Schweitzer of North Carolina State University conducted tests that also revealed the presence of collagen in the T. rex remains.
In one experiment, antibodies that normally react in the presence of chicken collagen reacted strongly to the dinosaur protein, suggesting a similar molecular identity.
Multiple Tests
For the protein sequencing study, Asara's team isolated seven fragmentary chains of amino acids—the building blocks of proteins—from the T. rex specimen.
The results are by far the oldest such data ever recovered. Previously, the earliest protein sequence data came from a 300,000-year-old mammoth specimen.
Asara's team extracted the amino acids using a highly refined version of the analytical technique known as mass spectrometry.
They also used the technique to isolate more than 70 amino acid
sequences from a mastodon thought to be between 160,000 and 600,000 years old.
Comparing the dino and mastodon samples to data from modern animals allowed the team to identify sequences that link the ancient amino acids to modern collagen.
Schweitzer and colleagues independently used a variety of chemical and molecular tests to identify the preserved collagen.
Both of the new studies, which will appear in tomorrow's edition of the journal Science, were conducted using the same unusual T. rex remains Schweitzer and others first described in 2005.
In that report the researchers described the seemingly inexplicable preservation of soft tissues—including branching blood vessels and bone matrix—in a T. rex fossil from Wyoming.
Some experts were immediately skeptical, saying that preservation of organic material over such a vast period of time should not be possible.
"The accepted viewpoint is that collagen, like other organic molecules, will degrade relatively rapidly, so that after a maximum of about a hundred thousand years nothing will remain," Schweitzer acknowledged.
But when conditions for preservation are just right, she said, "degradation rates may differ from predictions. Data from both [new] papers suggest that original protein may be preserved."
Burden of Proof
Hendrik Poinar is an expert in fossil proteins and DNA at McMaster University in Ontario, Canada.
Like others in the field, he had questioned whether Schweitzer's 2005 report made a sufficiently strong case that the preserved tissues came from a T. rex and were not the result of more recent contamination.
The new studies have him more convinced.
"I'd have to say, I'm more optimistic about it than I was previously," Poinar said. "Now the burden of proof is on the skeptics."
One self-proclaimed skeptic is Christina Nielsen-Marsh, an expert on ancient bone proteins at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
"I would love it to be true," she said of the new T. rex findings. "But I do have serious doubts. I know of no other research group that has been able to extract—let alone sequence—indigenous proteins from fossils older than a million years.
"Based on what we presently understand, these T. rex sequences make no sense at all," Nielsen-Marsh said.
"That doesn't mean they are wrong. But if they are right, then we all need to rethink how molecules survive in the geological environment."
Schweitzer and her collaborators, including paleontologist John Horner of Montana State University, agree that their discovery should prompt such a rethinking, which could lead to changes in how fieldwork is conducted.
In a Wednesday teleconference, the researchers said several factors may help explain the unusual protein preservation in the T. rex fossil.
The size and density of some dinosaur bones, they said, may help shield internal structures from decay. And bones preserved in dry sandstone may resist degradation better than those trapped in moist soil layers.
Horner said that a central lesson is that paleontologists need to dig deeper to find exceptionally well-preserved fossils.
"If we spend time getting as deep into the sediment as we can, I think we're going to find that many specimens are like this," Horner said.
"This summer we're sending out a major expedition, going worldwide looking for exquisite preservation."
Extensive Sequences
On the laboratory side, Harvard's Asara said, researchers should expect further improvements in analytical techniques, facilitating the recovery of protein sequences from very old remains.
Previous beliefs that proteins rarely if ever survive beyond a few hundred thousand years have now been proven false, he said.
"The mastodon [analysis] revealed a lot of protein," Asara said. "We can now get extensive sequences from species half a million years old, if they are very well preserved."
The researchers said that obtaining more ancient sequences should lead to a powerful new synthesis of paleontology and molecular biology.
"We can now begin [to study] evolutionary relationships between modern and extinct organisms at the molecular level," Asara said.
Quote from: Queequeg on January 03, 2010, 10:03:41 PM
Still doesn't really answer my original question. How did the Avian-Dinosaur system come about? Crocodiles, Pterosaurs and Dinosaurs aren't that that distant of relations; I'd think that modern crocodiles would at least have some remnants of the prototype avian respiratory system.
Crocodilians are archosaurs, not dinosaurs. Only dinosaurs and their close relatives seem to have that adaptation.
Tim, that really isn't the same thing.
Quote from: alfred russel on January 03, 2010, 10:40:48 PM
Tim, that really isn't the same thing.
However it points to how similar the animals were biologically. If many of their proteins and blood cells/vessels were similar, it's not a huge step to say their breathing system was as well, especially when the physical bone structure points in that direction.
Also, I totally fucked up the posting of those articles, it's fixed now.
I like how a thread that Quee was mocked for is actually very interesting. :hug:
Quote from: Faeelin on January 03, 2010, 10:53:14 PM
I like how a thread that Quee was mocked for is actually very interesting. :hug:
A lot of his threads turn out that way, but without a doubt he deserved to be mocked for this opening post.
Quote from: jimmy olsen on January 03, 2010, 10:05:46 PM
There was a much lower amount of oxygen in the mesozoic period, so a more efficient breathing mechanism was selected for.
This is a good point--there is a concept that all large animals (basically anything much larger than a foot or two long) are essentially unsustainable and doomed to die out in a future extinction event. In extinction events, all species suffer, but larger animals almost vanish. So the future belongs to organ systems that compete best within smaller animals.
The disadvantage of an avian system is its requirement for a lot of space. This is accentuated in a small animal. In a time of low oxygen levels, the better efficiency of the system seems to have overcome this problem. But when oxygen levels rose, the age of mammals began.
Quote from: alfred russel on January 03, 2010, 11:18:45 PM
Quote from: jimmy olsen on January 03, 2010, 10:05:46 PM
There was a much lower amount of oxygen in the mesozoic period, so a more efficient breathing mechanism was selected for.
This is a good point--there is a concept that all large animals (basically anything much larger than a foot or two long) are essentially unsustainable and doomed to die out in a future extinction event. In extinction events, all species suffer, but larger animals almost vanish. So the future belongs to organ systems that compete best within smaller animals.
The disadvantage of an avian system is its requirement for a lot of space. This is accentuated in a small animal. In a time of low oxygen levels, the better efficiency of the system seems to have overcome this problem. But when oxygen levels rose, the age of mammals began.
Well, mammals only had the opportunity for their age to begin because of a cosmological fluke.
Quote from: jimmy olsen on January 03, 2010, 11:39:11 PM
Quote from: alfred russel on January 03, 2010, 11:18:45 PM
Quote from: jimmy olsen on January 03, 2010, 10:05:46 PM
There was a much lower amount of oxygen in the mesozoic period, so a more efficient breathing mechanism was selected for.
This is a good point--there is a concept that all large animals (basically anything much larger than a foot or two long) are essentially unsustainable and doomed to die out in a future extinction event. In extinction events, all species suffer, but larger animals almost vanish. So the future belongs to organ systems that compete best within smaller animals.
The disadvantage of an avian system is its requirement for a lot of space. This is accentuated in a small animal. In a time of low oxygen levels, the better efficiency of the system seems to have overcome this problem. But when oxygen levels rose, the age of mammals began.
Well, mammals only had the opportunity for their age to begin because of a cosmological fluke.
Arguably. I say arguably for two reasons: first, a mass extinction event at some future point was inevitable. Second, it seems as though mammal life began to explode in diversity 85 million years ago, as opposed to when the asteroid(s) hit 65 million years ago.
Quote from: alfred russel on January 03, 2010, 11:50:51 PM
Arguably. I say arguably for two reasons: first, a mass extinction event at some future point was inevitable. Second, it seems as though mammal life began to explode in diversity 85 million years ago, as opposed to when the asteroid(s) hit 65 million years ago.
Added to that, there were plenty of small dinos that could and did compete with primitive mammals, and yet the mammals won out. It's not so much that dinos were better then mammals, it's that they got to the niches first. it's hard to break into, and specialise, in niches already occupied.
Quote from: alfred russel on January 03, 2010, 11:01:15 PM
Quote from: Faeelin on January 03, 2010, 10:53:14 PM
I like how a thread that Quee was mocked for is actually very interesting. :hug:
A lot of his threads turn out that way, but without a doubt he deserved to be mocked for this opening post.
You may not believe it, but I kind of expected that. We have more than an interest in the topic, and I kind of like roleplaying here.
Quote from: HVC on January 04, 2010, 12:26:39 AM
Quote from: alfred russel on January 03, 2010, 11:50:51 PM
Arguably. I say arguably for two reasons: first, a mass extinction event at some future point was inevitable. Second, it seems as though mammal life began to explode in diversity 85 million years ago, as opposed to when the asteroid(s) hit 65 million years ago.
Added to that, there were plenty of small dinos that could and did compete with primitive mammals, and yet the mammals won out. It's not so much that dinos were better then mammals, it's that they got to the niches first. it's hard to break into, and specialise, in niches already occupied.
This is far more obviously the case after the KT extiction event than during the Triassic period, when therapsid/mammalform predators lost out first to general archosaurs and then to dinosaurs. It also is not so easily clear cut; huge bipedal almost entirely dromeaosaur or ornithoraptor like birds were among the top predators of the Eocene.
Quote from: alfred russel on January 03, 2010, 11:01:15 PM
A lot of his threads turn out that way, but without a doubt he deserved to be mocked for this opening post.
Whether he deserves it or not, he gets mocked for virtually every thread he starts here. It's part of his schtick, really.
Quote from: jimmy olsen on January 03, 2010, 11:39:11 PM
Well, mammals only had the opportunity for their age to begin because of a cosmological fluke.
Mammals were already stepping up in the late Cretaceous. For small animals, the Age of Dinosaurs ended in the middle Cretaceous.
Quote from: Neil on January 04, 2010, 08:11:40 AM
Quote from: jimmy olsen on January 03, 2010, 11:39:11 PM
Well, mammals only had the opportunity for their age to begin because of a cosmological fluke.
Mammals were already stepping up in the late Cretaceous. For small animals, the Age of Dinosaurs ended in the middle Cretaceous.
I thought this was one of the most interesting questions; why is it that we kind of took over the small terrestrial land niches in the mid-late Cretaceous, along with the birds? Why is it that the big birds had a wonderful Eocene, but can't seem to compete with modern quadrupedal mammals in most terrestrial niches, while the birds seem to have some manner of big advantage over bats? Why did our Therapsid ancestors loose out in the Triassic to come back stronger than ever after the Age of Dinosaurs?
Quote
The disadvantage of an avian system is its requirement for a lot of space. This is accentuated in a small animal. In a time of low oxygen levels, the better efficiency of the system seems to have overcome this problem. But when oxygen levels rose, the age of mammals began.
This is really interesting; it would explain why even the smallest bird often appears "puffy" when compared with the smallest bat, as the bird would no doubt need room for the superior Avian-style lungs. You'd think that the mammalian size advantage would mean quite a bit, but I suppose the birds have certain other advantages.
Quote
Crocodilians are archosaurs, not dinosaurs. Only dinosaurs and their close relatives seem to have that adaptation.
AR posited that the Pterosaurs had something similar to the Avian system, and I think that what we would see in the early, possibly warm blooded (there is a pretty persuasive argument that cold bloodedness was returned to in the Crocodillians, as their ancestors had the gait and build of fast animals, like some of the earlier dinosaurs and relatives of pterosaurs) crocodiles would be similar, and I'd *guess* that we would see something *descended from* and probably resembling at the early stages of fetus development to the Avian-Dinosaur-Pterosaur system. I doubt that a completely new, more efficient respiratory system somehow sprung up anew in the relatively small time between the Crocodiles and the Pterosaurs branched off from the Dinosaurs.
An interesting question that hasn't been broached yet; do marsupials and placental mammals have a more efficient, or at least somehow better reproductive system than the "reptiles" and birds?
Quote from: Queequeg on January 04, 2010, 09:15:41 AM
An interesting question that hasn't been broached yet; do marsupials and placental mammals have a more efficient, or at least somehow better reproductive system than the "reptiles" and birds?
Certainly more robust. Not tying the mother down to a single physical location is also very handy.
Quote from: Queequeg on January 04, 2010, 01:06:22 AM
This is far more obviously the case after the KT extiction event than during the Triassic period, when therapsid/mammalform predators lost out first to general archosaurs and then to dinosaurs. It also is not so easily clear cut; huge bipedal almost entirely dromeaosaur or ornithoraptor like birds were among the top predators of the Eocene.
I think the theory is that during the triassic the archosaurs took over because of the generally arid conditions where reptiles have certain advantages regarding water retention (all land was in one continent at the time and temperatures were supposedly higher). Tim pointed out that dinosaurs, many if not all of which had avian respiratory systems, would be further advantaged in low oxygen environment.
We still have birds that are large and flightless--the ostrich, flamingo, and pengiuns come to mind. There was never an era of absolutes--if dinosaurs had totally dominated the mesozoic we wouldn't have modern day reptiles or mammals.
Quote from: Neil on January 04, 2010, 08:11:40 AM
Quote from: jimmy olsen on January 03, 2010, 11:39:11 PM
Well, mammals only had the opportunity for their age to begin because of a cosmological fluke.
Mammals were already stepping up in the late Cretaceous. For small animals, the Age of Dinosaurs ended in the middle Cretaceous.
Don't birds count as small animals and as dinosaurs? There were a lot of them in the late Cretaceous.
Quote from: jimmy olsen on January 04, 2010, 09:42:01 AM
Quote from: Neil on January 04, 2010, 08:11:40 AM
Quote from: jimmy olsen on January 03, 2010, 11:39:11 PM
Well, mammals only had the opportunity for their age to begin because of a cosmological fluke.
Mammals were already stepping up in the late Cretaceous. For small animals, the Age of Dinosaurs ended in the middle Cretaceous.
Don't birds count as small animals and as dinosaurs? There were a lot of them in the late Cretaceous.
True, but birds mostly avoided being land animals, and dinosaurs never ruled the skies.
Quote from: Queequeg on January 04, 2010, 09:15:41 AM
An interesting question that hasn't been broached yet; do marsupials and placental mammals have a more efficient, or at least somehow better reproductive system than the "reptiles" and birds?
I buy into the argument that bacteria are actually more evolved than we are--just because they don't have structures that we consider advanced doesn't change that they evolve just like everything else. And their shorter generation times mean there has been much more opportunity for natural selection to take place.
Quote from: alfred russel on January 04, 2010, 09:48:54 AM
Quote from: Queequeg on January 04, 2010, 09:15:41 AM
An interesting question that hasn't been broached yet; do marsupials and placental mammals have a more efficient, or at least somehow better reproductive system than the "reptiles" and birds?
I buy into the argument that bacteria are actually more evolved than we are--just because they don't have structures that we consider advanced doesn't change that they evolve just like everything else. And their shorter generation times mean there has been much more opportunity for natural selection to take place.
Sure, but we have created war, New York and Harry Potter. Who is really superior?
Quote from: The Brain on January 04, 2010, 09:51:46 AM
Sure, but we have created war, New York and Harry Potter. Who is really superior?
I could repost a few Lettow classics to show that e. coli have the edge.
Quote from: alfred russel on January 04, 2010, 09:48:54 AM
Quote from: Queequeg on January 04, 2010, 09:15:41 AM
An interesting question that hasn't been broached yet; do marsupials and placental mammals have a more efficient, or at least somehow better reproductive system than the "reptiles" and birds?
I buy into the argument that bacteria are actually more evolved than we are--just because they don't have structures that we consider advanced doesn't change that they evolve just like everything else. And their shorter generation times mean there has been much more opportunity for natural selection to take place.
I don't accept the concept "more evolved". I can accept the concept "better suited to it's environment", but that is only determined when one species has gone extinct and the other hasn't.
Quote from: Viking on January 04, 2010, 10:14:29 AM
I don't accept the concept "more evolved". I can accept the concept "better suited to it's environment", but that is only determined when one species has gone extinct and the other hasn't.
This is true and it isn't. One of the earliest amphibians would probably not do all that well in a cenozoic swamp; it would be a total anachronism. Similarly, I think some of the earliest dinosaurs would not do so hot in the Cretaceous. But it is obviously difficult to be sure; I don't think Possums have changed that much in form the time of the Dinosaurs, but they are still resilient fuckers.
We probably shouldn't use the term "more evolved". "Basal", meaning conservative of form, is probably more accurate, and compare it to derived/advanced.
AR, have you seen the Field Museum's remodeled paleontology wing? Afraid that I haven't. I was a huge dinosaur nut as a little kid, and my parents got a ticket to the opening night of the last remodeling (when they had the old ABC Newscaster who now does A&E biography talking about events in the Paleozoic). One of the best nights of my childhood. Still remember how excited I was that I was able to make a sound like some kind of big ornithopod.
Quote from: Queequeg on January 04, 2010, 10:22:28 AM
Quote from: Viking on January 04, 2010, 10:14:29 AM
I don't accept the concept "more evolved". I can accept the concept "better suited to it's environment", but that is only determined when one species has gone extinct and the other hasn't.
This is true and it isn't. One of the earliest amphibians would probably not do all that well in a cenozoic swamp; it would be a total anachronism. Similarly, I think some of the earliest dinosaurs would not do so hot in the Cretaceous.
We probably shouldn't use the term "more evolved". "Basal", meaning conservative of form, is probably more accurate, and compare it to derived/advanced.
AR, have you seen the Field Museum's remodeled paleontology wing? Afraid that I haven't. I was a huge dinosaur nut as a little kid, and my parents got a ticket to the opening night of the last remodeling (when they had the old ABC Newscaster who now does A&E biography talking about events in the Paleozoic). One of the best nights of my childhood. Still remember how excited I was that I was able to make a sound like some kind of big ornithopod.
I haven't seen it.
"More evolved" might be a terrible phrase, but if evolve means "to undergo evolutionary change" then I'd say bacteria are "more evolved" than mammals. But that is arguable.
Quote from: Queequeg on January 04, 2010, 09:12:47 AM
I thought this was one of the most interesting questions; why is it that we kind of took over the small terrestrial land niches in the mid-late Cretaceous, along with the birds?
IIRC insect and the insect explosion brought about by flowering plants.
Quote from: alfred russel on January 04, 2010, 10:31:24 AM
"More evolved" might be a terrible phrase, but if evolve means "to undergo evolutionary change" then I'd say bacteria are "more evolved" than mammals. But that is arguable.
Considering that bacteria exist in symbiosis with all forms of multicellular life with which I am familiar, I'm inclined to think of these things as just in a different category. Like comparing orange chicken with a single orange.
Quote from: Viking on January 04, 2010, 11:17:08 AM
How is it not true?
A human being is a more complex organism than a Myllokunmingia. I don't think "more evolved" would be unfair.
Quote from: Queequeg on January 04, 2010, 05:10:21 PM
Quote from: Viking on January 04, 2010, 11:17:08 AM
How is it not true?
A human being is a more complex organism than a Myllokunmingia. I don't think "more evolved" would be unfair.
I think it would be.
Just reminded by this thread: over Christmas I had opportunity to visit the Beringia Centre in Whitehorse. There are some spectacular fossil finds in northern Yukon of Ice Age remains, since it was the center of the Beringia Land Bridge. The bones and models they had on display were very cool. :nerd:
Why am I not surprised that there is a Beria Centre in Whitehorse?
Quote from: The Brain on January 04, 2010, 08:07:14 PM
Why am I not surprised that there is a Beria Centre in Whitehorse?
:rolleyes:
http://www.beringia.com/
Quote from: Queequeg on January 04, 2010, 05:10:21 PM
Quote from: Viking on January 04, 2010, 11:17:08 AM
How is it not true?
A human being is a more complex organism than a Myllokunmingia. I don't think "more evolved" would be unfair.
If you look at it in terms of changes in DNA, I would think the rates of change would be much higher in a population of bacteria rather than humans (at least those with conjugation). That seems like one logical way to quantify evolutionary change.
If it was a Laventri Beria center, I'd get my tickets STAT.
My mere presence would swell the tourism dollars up there to 20 bucks for the year.
The thing with living organisms is that they've all share the same lineage. Since all organisms share the same line of decent all the lines of decent are the same age. All organisms would be at the same level of "evolved". Complexity is different issue but more complex organisms are not more evolved organisms.
Quote from: Queequeg on January 04, 2010, 05:10:21 PM
Quote from: Viking on January 04, 2010, 11:17:08 AM
How is it not true?
A human being is a more complex organism than a Myllokunmingia. I don't think "more evolved" would be unfair.
That's a bit subjective there defining a complex organism as "more evolved", simple organisms can be almost perfectly adapted to their environment. Furthermore you have many apparently simple organisms which have many times more genes than we do, sure they are more complex than us? Your anthropocentrism dissapoints me.
Quote from: Viking on January 05, 2010, 01:51:51 AM
Quote from: Queequeg on January 04, 2010, 05:10:21 PM
Quote from: Viking on January 04, 2010, 11:17:08 AM
How is it not true?
A human being is a more complex organism than a Myllokunmingia. I don't think "more evolved" would be unfair.
That's a bit subjective there defining a complex organism as "more evolved", simple organisms can be almost perfectly adapted to their environment. Furthermore you have many apparently simple organisms which have many times more genes than we do, sure they are more complex than us? Your anthropocentrism dissapoints me.
How do you evolve when you are perfectly adapted to your environment?
Quote from: Razgovory on January 04, 2010, 11:53:48 PM
The thing with living organisms is that they've all share the same lineage. Since all organisms share the same line of decent all the lines of decent are the same age. All organisms would be at the same level of "evolved". Complexity is different issue but more complex organisms are not more evolved organisms.
A lot of factors influence the rates of genetic change besides the passage of time: average generation time, population size, mutation rates (these are not the same as there are different environmental factors, as well as different intracelluar controls), sexual life cycles (typical diploid sexual such as us, haplodiploidity in many eusocial species, and the extent asexuality is present), and the extent genes can be integrated from the environment.
Raz, think about it this way: if we put a 20 year generation time period on humans and our recent ancestors, in the past 5 million years we've had 250,000 generations. It's possible for bacteria to cram that many generations into a human lifetime.