what killed off dinosaurs?

[tedkaw]

I guess this can be considered an ancient topic. It doesn't get any more ancient than dinosaurs. Popular theories say the dinosaurs went extinct because of an asteroid hit on earth. Other people say Volcanic eruptions or earthquakes or whatever. All I can picture is an Armageddon type atmosphere..

What do you think killed the dinosaurs?

[Commander]

I've heard that scientists think a huge asteroid crashed near the Yucatan Penninsula in Mexico near the Gulf of Mexico... and that impact could have been large enough to kick a lot of dirt into the atmosphere. This would cause the earths temperature to change and vegetation would die from a lack of sunlight. It all had a chain effect and eventually killed off the dinosaurs..

[Obelia]

I know it doesn't seem like it, but we're in the middle of another great extinction event. This one is caused mainly by foreign travel. For example, grey squirrels are introduced into Britain where they kill off the native reds. Or rats are carried by ships to where the ground-nesting dodos lived, and eat their eggs. Rabbits in Australia is another example.

A lot of species are dying out because they can't compete with recently introduced aliens. The most damaging of these alien species is man, but we're not the only one.

I think the dinosaurs had a similar problem, for different reasons. Obviously they didn't have boats and planes to contend with, but they did have shifting landmasses. I believe the pass between America and Siberia opened up. That would have introduced a lot of new species, some of which would have killed off less dinosaurs that were not as well adapted as they were.

[kahn]

so maybe if the land masses are still shifting, then in a million years time when North America crashes into Asia, we will all fight each other off and become extinct

[murph]

I do agree with the scientists in that i believe it was an asteroid. It does make sense, what with the theory of perpetual darkness caused by the dirt in the atmosphere. Although, why it didn't kill off all life is another question...

[Fredto]

An asteroid make sense if you don't dig too deep.

Yes, all dinosaurs have been killed by an asteroid but left all other life forms intact?

What about the crocodiles? They are almost direct descendants of the dinosaurs.

I think the migration of new species, the ice age and the shifting of landmasses are the most plausible explanations.

[Commander]

Haven't roaches been around since the time of the dinosaurs? man nothing kills them but a can of raid.

[tjadams]

I think the migration of new species, the ice age and the shifting of landmasses are the most plausible explanations.


I think an asteroid did strike the earth, but, it wasn't the fait accompli wound. Coupled with that strike, plate tectonics & atmospheric changes were the Hell broth that did them in.

[duckmom7]

I agree, adams...it was a combination of things, many of them atmospheric...
also, we have to think about the great ice melts that could have cut off various species from their migratory grounds, or even drowned out many species. Those who survived were the ones who learned to adapt.

[Richard Stanbery]

I think back to all those drawings of Romans and other ancient men/hunters fighting dinos (surprisingly well drawn and accurately) and the cave drawings, dragon stories, etc...and I wonder if the dinos all really did dies off in some kind of mass extinction. I just have the mixed idea that they died off slowly and gradually for some reason. Maybe the dragons of the middle ages were dinos remnants.

I just find it strange that every ancient culture had dragon legends. I also find it strange that Herodotus, the father of modern history, claimed that he personally went to Arabia to see the winged serpent. He commented that it is well that they dont breed well, else humanity could not withstand them.

Conventional science tells us that this is impossible, but who listens to that anyway?...>

[duckmom7]

Good Answer, Richard!

[tjadams]

I think back to all those drawings of Romans and other ancient men/hunters fighting dinos (surprisingly well drawn and accurately) and the cave drawings, dragon stories, etc...and I wonder if the dinos all really did dies off in some kind of mass extinction. I just have the mixed idea that they died off slowly and gradually for some reason. Maybe the dragons of the middle ages were dinos remnants....>

Be reminded about dinosaurs living into 'modern' times, they couldn't have. The atmosphere was a lot richer with oxygen in their times which aided some of the big ones to grow as large as they did and the big ones to fly as they did.

[Lucius]

The animals that survived the atmospheric consequences of a giant meteor strike would have been those which can survive by eating rotted vegetation and carcasses, like crocs and possums and such.

[Richard Stanbery]

I have a buddy that owns a pet rabbit that his kids call "Mr. Bun-Bun". He feeds it rabbit feed, but it also eats meat, like hamburger and chicken. That's strange in my book, but so it does (and likes it). I also know of coyotes in the wild that eat watermelons and fruit. I don't know how that applies to this thread, I just tossed it in as an aside.

[Heidi XX]

I guess this can be considered an ancient topic. It doesn't get any more ancient than dinosaurs. Popular theories say the dinosaurs went extinct because of an asteroid hit on earth. Other people say Volcanic eruptions or earthquakes or whatever. All I can picture is an Armageddon type atmosphere..

What do you think killed the dinosaurs?

Actually,the Dinosaurs are not all extinct! Crocadiles and huge gohannas and turles are all part of the Dinosaurs family.

What killed the rest of the Dinosaurs,i have only three theoires or opinions.
One that an astrunoid hit the earth or the Dinosaurs ate them selfs out.
The other one is that the other Dinosaurs could not change there bodies to match the earth changing times.

[Edratman]

[quote=Richard Stanbery;69259]
I just find it strange that every ancient culture had dragon legends. I also find it strange that Herodotus, the father of modern history, claimed that he personally went to Arabia to see the winged serpent. He commented that it is well that they dont breed well, else humanity could not withstand them.

[/ quote]

In some article I read a long time ago the author forwarded the opinon that the universal dragon legend was attributable to dinosaur fossils. While there is no way to verify or refute this theory, it made a lot of sense to me.

[tjadams]

[quote=Richard Stanbery;69259]
I just find it strange that every ancient culture had dragon legends. I also find it strange that Herodotus, the father of modern history, claimed that he personally went to Arabia to see the winged serpent. He commented that it is well that they dont breed well, else humanity could not withstand them.

[/ quote]

In some article I read a long time ago the author forwarded the opinon that the universal dragon legend was attributable to dinosaur fossils. While there is no way to verify or refute this theory, it made a lot of sense to me.


I heard of the same theory which makes perfect sense to people who thought a shooting star was something more than it was.

[snow]

Sometimes I wonder if people naturally assume that something big had to happen to wipe out the dinosaurs.

So we have a whole group of animals who are as long as some buses. How much food does it take to feed an animal this size? At what point is all of the food gone? So if there is no food for the small animals and they die out, this means there is no food for the meat eaters because the small animals have died out.

Could it just be that they got too big for their own good?

[PADDYBOY]

Some dinosaurs were very large, but we don't really know how numerous they were at any given time ? So they may have sacrificed large population for large inividual size, this would make them very vulnerable to a changeing enviroment.
On the the other hand, cold blooded animals eat less than warm blooded animals, so who knows ? I don't.

[Heidi XX]

I guess this can be considered an ancient topic. It doesn't get any more ancient than dinosaurs. Popular theories say the dinosaurs went extinct because of an asteroid hit on earth. Other people say Volcanic eruptions or earthquakes or whatever. All I can picture is an Armageddon type atmosphere..

What do you think killed the dinosaurs?
Not all species of dinosaurs all died out!
The Austrailan Croc and the American alligator are from dinosaurs spieces,so is the bird/bat species and the lizard species.
There all from the dinosaur spieces!

The real question is,what killed all the Huge popualar dinosaurs?
In space there was a mixture of dust and chemicals in the air caused a huge explosion causing rocks to be deployed in the space atphoshire.
Unfortunatly for the dinosaurs,one huge rock was deployed straight for earth,when the rock hit,every bit of the earth was destroyed.

Huge dinosaurs had no where to go, as for the flying dinosaurs (birds/bats) and small like dinosaurs (crocs/alligators/lizards)had one place to escape.

So we do have dinosaours still with us living with us right now.

[PADDYBOY]

There weren't many mammal species around at the time of the dinosaurs, probably due to large carnivorous reptiles eating them :eek:
It was assumed for a long time that mammals were no larger than shrews, although, I believe some fossils have recently been found of a beaver-like aquatic creature (about the size of a beaver :D )
Anyway, it is generally believed, that had dinosaurs not been wiped out by whatever ? We wouldn't be here.

[Serena]

An asteroid is a plausible suspect for a significant number of deaths within a certain diameter, but I don't think it was the dominant terminator. Others theories point to climate change, suffocation from low oxygen levels, meteor showers and viral infections which all have their hints of possibilities.

Failure of adaption due to climate change is like to be a more probable cause according to a number of researchers, thus ending in a gradual extinction. I think I find this a bit more credible, I'm just not sure if one asteroid can eradicate an entire earthly population with one blow despite the conditions. It would have to be a multitude causes.

[DesertPilot]

The Yukatan asteroid impact is well established. And by wiping out the food supply, it was pretty much guaranteed to knock out Big Things With High Metabolisms That Need Lots Of Food (e.g., dinosaurs) while leaving Tiny Things (shrews) and Cold-Blooded Things (alligators and talk-show hosts) That Don't Need As Much Food in reasonable shape. And the modern consensus seems to be that the Cretacious Extinction happened in a snap, which is pretty much what you'd expect if it was caused by an impact.

The big question is: was anything else going on before that? Barney and his pals had survived major environmental stresses before, why did they pack it in after that one whimpy little asteroid? Well, maybe it wasn't so whimpy. Or little. But you know what I mean.

It's possible that some other factor was at work -- some large-scale global climate shift, increase in the number of talk-show hosts, or that like -- to put dinosaurs under pressure, and what might otherwise have been an unnoticed asteroid impact ("WHAM!" "Did you notice that?" "How could I? I'm a dinosaur! I have a brain the size of a walnut!") delivered the finishing touch.

[Heidi XX]

Err...everyones missing the point! Some dinosours are living right now! Just not the huge cool ones like The T- Rex and ect....

[Rosicrucian]

The Austrailan Croc and the American alligator are from dinosaurs spieces

No not really, the crocodilians and the dinosaurs do have common ancestors but the two species branched out from this ancestor about the same time and developed simultaneously. So the crocs are more like the cousins of the dinosaurs, rather than having descended from them. :)

[Rosicrucian]

There weren't many mammal species around at the time of the dinosaurs, probably due to large carnivorous reptiles eating them :eek:
It was assumed for a long time that mammals were no larger than shrews, although, I believe some fossils have recently been found of a beaver-like aquatic creature (about the size of a beaver :D )
Anyway, it is generally believed, that had dinosaurs not been wiped out by whatever ? We wouldn't be here.

I agree, mammals got to grow only after the big dinosaurs were wiped out.

[Rosicrucian]

Sometimes I wonder if people naturally assume that something big had to happen to wipe out the dinosaurs.

So we have a whole group of animals who are as long as some buses. How much food does it take to feed an animal this size? At what point is all of the food gone? So if there is no food for the small animals and they die out, this means there is no food for the meat eaters because the small animals have died out.

Could it just be that they got too big for their own good?

There is plenty of evidence that the big dinosaurs' extinction was abrupt rather than a long drawn out process. Reptiles keep growing in size as long as they live and hence some dinosaurs got to be so big. Also, most of the big dinosaurs were herbivores and the earth was one continent back then, mostly tropical with lots of vegetation. T-Rexes were scavengers so shouldn't have had problems surviving to the extent that they got so big. So there was never a case of "all the food gone" even with all those biggies, though there were (as there are bound to be) famines from time to time.

[Toltec]

I would like to say it very definately wasn't me. Contrarary to what Patheya says.

[tjadams]

Don't forget, the planet's oxygen was much different than today's.

[Heidi XX]

No not really, the crocodilians and the dinosaurs do have common ancestors but the two species branched out from this ancestor about the same time and developed simultaneously. So the crocs are more like the cousins of the dinosaurs, rather than having descended from them. :)
Of cause,but every animal changes there body desighns to match the earth's climite over millions of years.

[DesertPilot]

I agree, mammals got to grow only after the big dinosaurs were wiped out.

Don't forget, there was a brief period after the dinos were gone but before the mammals ramped up their world dominance operation when giant birds ruled the earth. Gigantic flightless predatory birds that weighed more than a ton. That must have been... so cool! And we missed it! Darn!

[tjadams]

Of cause,but every animal changes there body desighns to match the earth's climite over millions of years.

But what about the people who emphatically state the world is only six thousand years old? :D :rolleyes: :cool:

[Gracchus]

There were probably several factors that contributed to the KT extinction.

Pangaea was breaking up, disrupting the annual migrations. Big vegetarian dinosaurs moving in herds would have to follow the food supply through seasonal migrations. The opening of rifts due to plate tectonics would have stopped not only the those that could not swim or fly, but the whole moving ecosystem that followed the migration. The continental drift would also have affected climate. Highly adapted species do not do well in a changing climate.

There was extensive vulcanism, which also would have contributed to changing climate and vegetation.

And of course, the great impact would have had huge immediate effects, splashing away part of the atmosphere, thinning the air, and by darkening, killing plant life on a world-wide scale.

The loss of vegetation would have further reduced the oxygen content of the atmosphere, and I suspect that those dinosaurs with inefficient respiratory systems, suffocated. Note that birds have hollow bones that connect to the respiratory system. So birds survived, while their larger cousins perished.

Finally, in his book "The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive?", P. Ward argues that life itself is a destabilizing influence, that invevitably leads to great extincions events.

:)


.

[Rosicrucian]

Of cause,but every animal changes there body desighns to match the earth's climite over millions of years.

Yes but the crocodiles havent changed over the millions of years, have they? That's why they, along with the sharks and horse shoe crabs, are known as living fossils. The crocs of today are the same as those during the times of the dinosaurs except for their sizes; modern day crocs are somewhat smaller.

[snow]

Some things I have always wondered is:

1) At what point did the west and southwest become desert?
2) Where were the dinosaurs concentrated? I can't picture them living say in the Rockies.
3) How slow can an abrupt extinction have to be?
4) How big was the largest herbivore? How much food did it need?


There is plenty of evidence that the big dinosaurs' extinction was abrupt rather than a long drawn out process. Reptiles keep growing in size as long as they live and hence some dinosaurs got to be so big. Also, most of the big dinosaurs were herbivores and the earth was one continent back then, mostly tropical with lots of vegetation. T-Rexes were scavengers so shouldn't have had problems surviving to the extent that they got so big. So there was never a case of "all the food gone" even with all those biggies, though there were (as there are bound to be) famines from time to time.

[Wobomagonda]

The Yucatan Meteorite impact is widely accepted as the event that caused the extinction of the dinosaurs. It did not kill them in one fell swoop, rather, the extinction rate is believe to be slower than extinction rates of animals today.

Source: Juniper, Tony. Saving Planet Earth, Harper-Collins Publishers, Published by permission from the BBC, 2007, pp. 13.

I included that in case you're interested, it's a fascinating book, and has some nice pictures.



oh almost forgot to add, further along it mentions that the meteorite didn't kill them itself, but it caused a shift in tectonic plates which caused earthquakes, and tsunamis and whatnot that lead to the gradual extinction due to habitat destruction as well as biological destruction of the dinosaurs themselves.

[Rosicrucian]

Some things I have always wondered is:

1) At what point did the west and southwest become desert?
2) Where were the dinosaurs concentrated? I can't picture them living say in the Rockies.
3) How slow can an abrupt extinction have to be?
4) How big was the largest herbivore? How much food did it need?

1. Not sure what part of the world you're referring to? Bear in mind the landscape of the earth was a lot different back then when the planet was basically just one continent. Antarctica was tropical, and the landmass known as India today was attached to it. As the tectonic shifts began to take place this landmass broke away from Antarctica and headed towards what's known as China today, crashing into it and creating the mountain range of Himalayas.

2. While I don't know how old the Rockies are, I doubt if they were around back in those days. The dinosaurs were spread all over, hence we have found their fossils in different continents.

3. One school of thought has been presented by Wobomagonda above. Another one states the "abrupt extinction" happened over a month as the air got extremely poisonous to breathe following the asteroid impact and the resultant geological chaos (like a spurt in the number of volcanoes erupting here and there, etc.).

4. Off the top of my head, I think the biggest dinosaur was teh Argentinosaurus (the last time I checked, which was a few years ago). Palaeontologists have discovered only the fossil of its head though. It is supposed to be a herbivore, about 28 ft long. Apart from that, the sauropods (those walking on four legs) are considered the biggest dinosaurs -- 14-18 ft long. This was primarily as their necks were really long, for the same reason a giraffe's neck is what it is.

[galteeman]

28 Metres long Rosi not feet.
The birds are the only surviving dinosaurs.

[Rosicrucian]

28 Metres long Rosi not feet.
Thanks for the correction then.
The birds are the only surviving dinosaurs.
Sadly yes. F*cking birds! :mad:

[Heidi XX]

28 Metres long Rosi not feet.
The birds are the only surviving dinosaurs.Yep ,Birds are dinosaurs,which i mention earlier!
Crocs and alligators have been prove that they belong to the Dinosaurs speices.
Not sure about tutouse and turtles,they been here just as long as the crocs and alligators have,so there is a possablity but i don't know for sure!

[Serena]

Much of the formation of the Rocky Mountains dates back to the Precambrian era and the Cretaceous era for younger realms of the mountains. Dinosaurs that would roam these areas of America would include Allosaurus, Stegasaurus, Apatosaurus, Brachiosaurus and Dryosaurus. Amphicoelias fragillimus, possibly the largest dinosaur discovered (and herbivore), measured about 170 ft and also ranged in these areas. The amount of food they consumed per day are sort of obscure because studies are still quite preliminary.

Theories of sudden extinctions for various taxa have been noted to take place periodically on a cycle of about 26 million years, many of these extinctions occurring in the later portion of each era. Some suggest that the solar system or the "ultimate forcing agent" may have produced meteor showers when the solar system oscillates vertically above and below the plane of the galaxy every 33 million years. But as more theories of extinction continue to surface, the rate extinction is more indecisive.

[garzan37]

A weird old man told me his theory one time its kinda funny. He said "Aries rock in Australia was a huge space rock (asteroid) hit the earth and split all the continents apart and all the female dinosaurs fell into the cracks. All the males became sexually frustrated and killed each other pretty quick but everything else survived becuase they were hermaphrodites at the time". I guess its a weird theory but a theory none the less. I think a Super Volcanoe could have been another possibility.

[Gracchus]

A weird old man told me his theory one time its kinda funny. He said "Aries rock in Australia was a huge space rock (asteroid) hit the earth and split all the continents apart and all the female dinosaurs fell into the cracks. All the males became sexually frustrated and killed each other pretty quick but everything else survived becuase they were hermaphrodites at the time". I guess its a weird theory but a theory none the less.

That's not a theory. It's a fanciful flight of imagination.

:rolleyes:

I think a Super Volcanoe could have been another possibility.

There was extensive vulcanism, probably related plate tectonics.

See for instance: http://en.wikipedia.org/wiki/Deccan_Traps (http://en.wikipedia.org/wiki/Deccan_Traps)

[galteeman]

Crocs and alligators have been prove that they belong to the Dinosaurs speices.

Don't think so.

[Chubz]

There were probably several factors that contributed to the KT extinction.

Pangaea was breaking up, disrupting the annual migrations. Big vegetarian dinosaurs moving in herds would have to follow the food supply through seasonal migrations. The opening of rifts due to plate tectonics would have stopped not only the those that could not swim or fly, but the whole moving ecosystem that followed the migration. The continental drift would also have affected climate. Highly adapted species do not do well in a changing climate.

There was extensive vulcanism, which also would have contributed to changing climate and vegetation.

And of course, the great impact would have had huge immediate effects, splashing away part of the atmosphere, thinning the air, and by darkening, killing plant life on a world-wide scale.

The loss of vegetation would have further reduced the oxygen content of the atmosphere, and I suspect that those dinosaurs with inefficient respiratory systems, suffocated. Note that birds have hollow bones that connect to the respiratory system. So birds survived, while their larger cousins perished.

Finally, in his book "The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive?", P. Ward argues that life itself is a destabilizing influence, that invevitably leads to great extincions events.

:)


.

This is a good post. :)

[Heidi XX]

Don't think so.
Crocs/Alligators/Birds and Dinosaurs are members of the reptile group "Archosauia"
Although the Dinosaurs were warm blooded and the Crocs and Alligators are cold blooded,so there is a missing link between these two species.

[Fluffybunny]

What do you think killed the dinosaurs?

I did :cool:

[PADDYBOY]

Crocs/Alligators/Birds and Dinosaurs are members of the reptile group "Archosauia"
Although the Dinosaurs were warm blooded and the Crocs and Alligators are cold blooded,so there is a missing link between these two species.


Sort of ?

Crocodiles, birds and dinosaurs are all descended from archosaurs (lizards) Crocodiles after birds, are the closest living relatives of dinosaurs.

Bear in mind Heidi, that the internal mechanisms of extinct beasties are unknowable ? So, although dinosaurs may have been warm blooded ? We don't really know. :confused:

[Gracchus]

Just to clear things up, the Sauria include:
The Tuatara
Mosasaurs, lizards and snakes
The Archosauria

The Archosauria include:
The Crocodilians
The Pterosaurs
The Dinosaurs

The Dinosaurs include:
The Ornithischians
The Sauropods
The Theropods (which include birds)

Prothero, Donald R. "Evolution:What the Fossils Say and Why It Matters,
(c) 2007 Columbia University Press

:)

[Heidi XX]

I did :cool:

Sort of ?

Crocodiles, birds and dinosaurs are all descended from archosaurs (lizards) Crocodiles after birds, are the closest living relatives of dinosaurs.

Bear in mind Heidi, that the internal mechanisms of extinct beasties are unknowable ? So, although dinosaurs may have been warm blooded ? We don't really know. :confused:

Just to clear things up, the Sauria include:
The Tuatara
Mosasaurs, lizards and snakes
The Archosauria

The Archosauria include:
The Crocodilians
The Pterosaurs
The Dinosaurs

The Dinosaurs include:
The Ornithischians
The Sauropods
The Theropods (which include birds)

Prothero, Donald R. "Evolution:What the Fossils Say and Why It Matters,
(c) 2007 Columbia University Press

:)
That's funny Fluffy Bunny! A little fluffy bunny destroying all the huge dinosaurs.Im laughing out loud.:D

Paddyboy,That's the case,which i believe my self,why arn;t the living animals not actually class as dinosaurs?
Its either you are apart of that group or you're not,but in this case,they are ralitives of dinosaurs but not actually dinosaurs them selfs.:confused: :)

Gracchus.
Great post,i did not know half of that.;)

[Serena]

Yes, rabbits are vicious creatures you know. ;)

http://www.pythonline.com/files/pythonline/images/MontyPythonKillerRabbit1.jpg

[PADDYBOY]

Paddyboy,That's the case,which i believe my self,why arn;t the living animals not actually class as dinosaurs?
Its either you are apart of that group or you're not,but in this case,they are ralitives of dinosaurs but not actually dinosaurs them selfs.:confused: :)


For the same reason we don't refer to ourselves as theropsids (synapsids) which is the reptilian group that mammals evolved from. Sometimes a species evolves or changes so much, that it hardly bears any similarity to what it used to be.
Birds used to be dinosaurs, dinosaurs used to be archosaurs and people used to be little nocturnal shrew like creatures, and so on.......

[PADDYBOY]

Okay, let's start of with the reptiles known as Anapsids. These beasties had solid skulls with openings for the spinal cord, nose and eyes.This type of skull still exists in Testutines (turtles, tortoise and terrapins) which may mean that turtles are descended from (living survivors) of Anapsids ? On the other hand, they may have reverted back to this state for the purpose of improving their armour (shells) It can be argued both ways so I won't commit.
Soon after the arrival of the first reptiles, they split into two branches. Synapsidia and Diapsidia.
Synapsidia, the mammal like reptiles ? or stem mammals ? had two holes in their skull, placed behind the eyes.
Diapsidia, also had two holes behind their eyes and another two higher up the skull. These holes lightened the skull and allowed for more flexible jaw muscles with extra strength, resulting in a more powerful bite.
Diapsids and the later Anapsids are classed as true reptiles....The Sauropsida, a group of Amniotes ( lay eggs on land) which includes all existing reptiles, Dinosaurs and birds.

The perminan is a geological period and system characterised by the diversity of evolving life forms about 299-251 million years ago.
With the ending of the Carboniferous period, reptiles became the dominant Tetrapod (four-footed, quadrapeds) while reptilmorphs labrynthodonts (amphibians) still existed.
The mammal like reptiles evolved the first large/ish beasties such as Pelycasaurs, Edaphosaurus and the carnivorous Dimetroden. They looked like big lizards with sails along their backs :cool:
In the mid permian, the climate turned dryer causing an adjustment in animal dominance. The primitive Pelycosuars were ousted by the more advanced therapsids, a group of synapsids which included mammals.
(other than mammals....all linages of the synapsids are now extinct )
The Anapsid reptiles with their huge skulls continued and flourished throughout the permian.The Pareisaurs grew huge in the late permian and, eventually disappeared by the end of the period. Testutines maybe their survivors as I mentioned earlier, maybe ?
Early in the period the diapsid reptiles split into two lineages, the Lepidaurs (ancestors of lizards,snakes) and Tuatarus.

Archosaurs and Dinosaurs later.......

[PADDYBOY]

The end of the permian period resulted in the greatest mass extinction known to us (the permian triassic mass extinction event) with most of the anapsids and synapsids dying out and being replaced by the Archosauromorph diapsids. The Archosaurs ! with their elongated hind legs and upright pose. The earlier varieties looking a bit like long legged crocodiles. Archosaurs became the dominant group during the triassic period (251-199 million years ago )
Many experts have classified Archosaurs by their ankles ? The earliest archosaurs had primitive ankles with the joint bending above the foot. Later, during the early triassic, the ankles formed into a proper joint which could rotate. So, from walking with sprawling limbs, they evolved into being able to walk with erect limbs.
(crocodiles can walk with sprawling or erect limbs depending on how much of a hurry they are in )
Ankle joints probably don't sound all that important but, believe me, they are.
Carrier constraint is the trouble reptiles have when they flex their bodies sideways during locomotion. It is very difficult to move and breathe simultaneously due to sideways flexing expanding one lung and compressing the other. This shunts stale air from one lung to the other instead of expelling it and making room for fresh air.

Archosaurs developed into dinosaurs , pterosaurs (flying reptiles) crocodiles and phytosaurs (similar to cocodiles but different, don't ask !)
Some dinosaurs grew into the largest land animals ever to have existed and giving the mesozoic period the title of Age Of The Reptiles.
Dinosaurs also developed into smaller critters including the theropds in the mid jurassic and of course, later becoming what we now know as birds.
The lepidosarosmorph diapsids (more similar to to lizards than archosaurs) may have been ancestors to sea reptiles developing into ichthyosaurs (giant marine lizards) and sauropterygians (similar to Nessie) who came to dominate the mesozoic seas.
The therapsids came under extreme pressure from the archosaurs in the mesozoic period and grew increasingly smaller and more nocturnal to avoid predation . The first mammals being the only survivors by the late jurassic.

[Bobby]

I know it doesn't seem like it, but we're in the middle of another great extinction event. This one is caused mainly by foreign travel. For example, grey squirrels are introduced into Britain where they kill off the native reds. Or rats are carried by ships to where the ground-nesting dodos lived, and eat their eggs. Rabbits in Australia is another example.

A lot of species are dying out because they can't compete with recently introduced aliens. The most damaging of these alien species is man, but we're not the only one.

I think the dinosaurs had a similar problem, for different reasons. Obviously they didn't have boats and planes to contend with, but they did have shifting landmasses. I believe the pass between America and Siberia opened up. That would have introduced a lot of new species, some of which would have killed off less dinosaurs that were not as well adapted as they were.

Interesting. Bakker, formerly of Yale University paleontolgy would agree with you to a degree. He believes it was the migrations of Old World Dinosaurs into the New World via the Bering land bridge. He asserts that the isolation of these two groups made each vulnerable to the pathogens of the other. It is a theory not favored by most but it is interesting, especially given the fact that somewhere around 20-40 percent of native Americans died of introduced diseases of the Europeans. Still, why didn't the Europeans die off in masses for the same reasons? I don't know.

[galteeman]

Jared Diamond tries to answer this question in 'Guns, Germs and Steel'.
He gives a number of possible answers which may all contribute.
1. The rise of dense human populations began later in the New World than the Old World.
2. The 3 most densely populated American areas, Andes, Mesoamerica and the Missippi valley never were connected enough to make one huge breeding ground for microbes to be exchanged, wheras Europe, North Africa, India and China were connected by Roman times.
3. Eurasian crowd diseases evolved out of diseases of domesticated herd animals such as cows and pigs, while there were very few domesticated animals in the Americas in comparison to Eurasia and they had no cows or pigs.

[PADDYBOY]

I think you guys should watch the movie...Aliens vs Predator...
Anyway, the dinosaurs were wiped out by predators from another planet ;)

[DesertPilot]

OK, here's food for thought. Suppose that towards the end of the Cretaceous Era, intelligent dinosaurs evolved who developed an advanced technological civilization, discovered atomic energy, and proceeded to wipe themselves out with a nuclear war. How would we ever know? Any radiation would have long since decayed, and the fossil record is sufficiently spotty that it could well have missed the few brief millenia during which these hypothetical Dino Sapiens built cities, freeways, shopping malls, history web sites, and the like.

[PADDYBOY]

Good thinking DesertPilot.
I'm thinkink to myself, if the dinosaurs develeped nuclear technology ? who's to say they didn't also develop rocket technology and space travel ?
Maybe they f*cked the planet up and decided to abandon it, leaving it to those furry little things called mammals to rebuild it ? whilst they (the dinosaurs) found themselves a nice pristine planet to colonise.
Oops. I've just had a horrible after thought. What if they f*ck up their new planet and decide to come bak to good ol Earth, and they're much more advanced than we are :eek:

[Belisarius]

Good thinking DesertPilot.
I'm thinkink to myself, if the dinosaurs develeped nuclear technology ? who's to say they didn't also develop rocket technology and space travel ?
Maybe they f*cked the planet up and decided to abandon it, leaving it to those furry little things called mammals to rebuild it ? whilst they (the dinosaurs) found themselves a nice pristine planet to colonise.
Oops. I've just had a horrible after thought. What if they f*ck up their new planet and decide to come bak to good ol Earth, and they're much more advanced than we are :eek:

You've been listening to David Icke haven't you? Stop it now. Step away from the computer, go have a beer and it'll all become clearer to you. :rolleyes::D

[DesertPilot]

Good thinking DesertPilot.
I'm thinkink to myself, if the dinosaurs develeped nuclear technology ? who's to say they didn't also develop rocket technology and space travel ?
Maybe they f*cked the planet up and decided to abandon it, leaving it to those furry little things called mammals to rebuild it ? whilst they (the dinosaurs) found themselves a nice pristine planet to colonise.
Oops. I've just had a horrible after thought. What if they f*ck up their new planet and decide to come bak to good ol Earth, and they're much more advanced than we are :eek:

Maybe they created mammals for use as servants and we rebelled and there was this big war during which we wiped out all twelve of their colonies and all their navy except for this one surviving warship which lead a rag-tag fleet of refugee ships to the lost Thirteenth Dinosaur Colony on... wait... I think somebody used this idea already... :)

[Bobby]

Anything Diamond says must be taken with a grain of salt. I don't consider this man a natural scientist at all, a social scientist maybe. His book Guns, Germs and Steel is a social commentary lacking in scientific credibility. No offense but I hold Diamond in very low regard.

[Lucius]

Anything Diamond says must be taken with a grain of salt. I don't consider this man a natural scientist at all, a social scientist maybe. His book Guns, Germs and Steel is a social commentary lacking in scientific credibility. No offense but I hold Diamond in very low regard.

Bobby,

Can you give an example or two of incredible things he wrote in that book?

[Bobby]

Bobby,

Can you give an example or two of incredible things he wrote in that book?

It's been many years since I read the book so I am going on memory here. I did write a 20 page critique of this book which floated around the internet for a while but I cannot find it anymore.

Diamond rationalizes the lack of animal husbandry in Africa and Native America by saying the animals native to those reasons were non-domesticable. He cites Wildebeests and Buffalo as being 'fierce' creatures and cites the difficulty of 'taming' them like the docile beasts of the fertile crescent and then Europe. This is bunk of the highest order. All animals are 'fierce' when in the wild and will resist control by humans. The pig is a perfect example. It has become a staple food for many regions of the world and yet in the wild the Boar is one of the most aggressive animals on earth. And yet SOME societies managed to tame them and breed them. The same is true of Buffalo today, there are many such farms.

Diamond also gives the Maori a free pass. There were two cultures competing in New Guinea, the Maori survived by obliterating the other. Diamond contends that the extinct tribe went that way because the food supply, the pith of a type of coconut ran out. But why did it run out? Becuase the native ate all the trees and didn't think to replant any. The will for present gratification won out over future gratification in my view. Had this other tribe ( i forget their name) thought to replant the trees after they ate them they would have insured their staple crop. Diamond refuses to blame peoples for bad ideas, he always answers 'it was the environment.

Diamond also states that 'geniuses' are born randomly and that the areas of the underdeveloped world didn't get their share by chance. I disagree strongly. I'm quite sure the Zulus, Cherokees, and other peoples had their geniuses. The difference is recognition of such exceptions and ordering the society to use such talent for the benefit of that society. It is far more likely that these societies shunned and maybe even killed such exceptional people because their ideas were 'new' and these societies did not embrace change of any sort.

Diamonds book is an attack on Western Civilization, nothing more. He basically states Western success is by 'luck' of the environment. He is an environmental determinist leaving out all the other factors that lead to the success or failure of a society. The Mayans were the only native Americans to employ the wheel, but they only used it for toys. They never used the wheel for anything further. Is this a result of the environment? The North American Indians never developed writing, Diamond has some environmental excuse for this but it is lame. The development of a written language has proven key to a societies success. It was not the environment that prevented this.

The southeastern united states had a staple similar to soy, and yet the native Americans never developed it and farmed it. It would have allowed them to stay put and thrive. Diamond states that the food source in question is related to ragweed and 'stinks' excusing the use of it on 'allergies' (which is impossible to ascertain) and the foul odor of it. Of course many cultures have foods that 'stink' to other people, another lame excuse.

While the environment plays a role in a societies success IDEAS also play a role, and of course ideas in the human sense are the movers and shakers of societies. Diamond gives short shrift to such a notion and devolves to environmental conditions as the end all and be all of all societies. Western man was just lucky he says. Luck, in my view, has very little to do with it.

[Lucius]

Bobby,

Thank-you for your considered reply.

It's been a long time for me too, and I might be conflating Diamond's theses with another's, but as I remember, his contention was that a "suite" of domestic plants and animals conferred an advantage on the civilizations of the Eurasian land-mass vis-a-vis the rest of the planet. That is, the number and variety of these is what made the difference. Over time, this "head-start" (such as draft animals) continued to lengthen as the peoples of Eurasia continued to emulate each other's successful innovations(like coins, eventually).

I think that saying that Diamond's book is nothing more than an attack on Western Civilization is a little over the top. As you say, ideas and attitudes played a role in the development of societies around the world. How could they not? But at the same time, having the advantages conferred by a large number of domestic plants and animals would have also played a role.

I mean, one thing leads to another. If one group has an advantage from the get-go, then that same advantage naturally allows for an increase of advantage over the centuries, especially in regard to population size. Increasing the population size is how you get people like Theophrastus and Copernicus.

Now, other parts of Eurasia also had the same natural advantages as Europe. This brings us back to geography and Gibbon(I think it was Gibbon). The geography of Europe is highly indented with several large islands offshore. That is, Europe is conducive to the formation of many active rivals whose emulation of each other's successes serves as a spur to progress. So while ideas are the movers and shakers of societies, the idea has to occur to somebody located somewhere.

If I recall correctly, Diamond mentions this phenomenon in passing and didn't find it convincing since India was most always divided into many states and no one there, uh, invented the microscope or whatever. But this totally elides (yes!) the influence of the caste system in India (while there was something like a caste system in Europe, it wasn't wholly inter-generational). Also, I think the social standing of women was somewhat less degraded in Europe than elsewhere, and they're half of the total.

So, what was I saying. Oh yeah. I don't think it's a co-incidence that the descendants of the people who started out with very many domestic plants and animals ended up taking over the world(whatever that means).

What if Mesopotamia had started out with just dogs and squash?

[PADDYBOY]

The bit that boggles my mind is, why did it take people so long to realise that if you drop a seed, it will grow ? Whether that plant was easier to domesticate than someone elses, or not.
I'm pretty sure that people realised the mechanics of agriculture long before they started to practice it. So why did it take them so long to adopt the idea ?
I can't help feeling that there were other forces at play here other than, some plants are easier to domesticate than others...

Also, I can't figure out why a European wild boar would be less difficult to domesticate than a gnu. You take the young from their parents at a young age and then you breed from the more docile members and not from the more aggresive, less biddable members and eventually you get a domesticated stock. It just takes time....

[galteeman]

Well with the seeds they were probably gathering wild ones and bringing them back to wherever they lived and some probably fell there around their hut or whatever. Next thing you know someone notices that they have sprouted.
One reason it took so long to adopt agriculture is because they were doing fine without it. The life of the early farmers was actually harder in many ways and had a less varied and nutritious diet than the hunter gatherers. The hunters don't suffer from crowd diseases, famines or tyranny like the poor farmers who slave away all day. I'd guess that people became farmers because they were forced to, not by choice. One group would become farmers, the excess of food and larger population woul enable this group to develope societal structures including chiefs and soldiers. This would enable them to conquer new territory and drive off or enslave the hunter/gatherers in that area, forcing them to be farmers to supply the tyrants with tribute etc. etc.
Most wild animals are impossible to domesticate. Zebra for instance, can't be domesticated no matter what you do.
Have a read of this which covers animal domestication.
http://bruceowen.com/foundworld/h201-09s-11-AnimalsAxesGerms.pdf


To be domesticable, a wild animal must have all of the following characteristics

- herbivore or omnivore

- carnivores need more food, since they eat herbivores

- grow quickly

- breed in captivity

- can’t be too dangerous to people

- respond to threats by standing, not running

- live in herds

- have dominance hierarchy that humans can co-opt

- tolerate living in dense groups, even in mating season

- point: this is a lot of requirements

- only a handful of large wild animals meet them all

[galteeman]

The Mayans were the only native Americans to employ the wheel, but they only used it for toys. They never used the wheel for anything further. Is this a result of the environment?

I think it is because they didn't have any large animals to pull carts in that part of the world at that time.

[galteeman]

Diamonds book is an attack on Western Civilization, nothing more. He basically states Western success is by 'luck' of the environment.

Well I didn't really get that impression from his books. Anyway isn't Western success only a recent thing. They had the ascendency in other parts of the world at various times when the West was far behind. Perhaps in another 1000 years some other part of the world will be ahead and the West will be a backwater.

[PADDYBOY]

Most wild animals are impossible to domesticate. Zebra for instance, can't be domesticated no matter what you do.
Have a read of this which covers animal domestication.


Sorry galteeman, but zebras have been domesticated in the past (Lord Rothschild and captain Horrace Hayes to name two) The problem with zebra is they are more easily spooked than the dometicated horse, so why bother with years of selective breeding to counter this when the domesticated horse is already available.....

[King of Rome]

isnt this not related to history but pre-history?

[PADDYBOY]

isnt this not related to history but pre-history?

Where would you suggest we discuss pre-history and archaeology if not in the ancient history forum ?
Perhaps the mods could move it somwhere more suitable to you....

[galteeman]

Sorry galteeman, but zebras have been domesticated in the past (Lord Rothschild and captain Horrace Hayes to name two) The problem with zebra is they are more easily spooked than the dometicated horse, so why bother with years of selective breeding to counter this when the domesticated horse is already available.....

Paddyboy I think that training the odd zebra to pull a carraige or to be tame is different than the domestication of the species.
The people who lived in sub-Saharan Africa had no access to horses yet they never domesticated Zebra, why?, because it can't be done.

[PADDYBOY]

Paddyboy I think that training the odd zebra to pull a carraige or to be tame is different than the domestication of the species.
The people who lived in sub-Saharan Africa had no access to horses yet they never domesticated Zebra, why?, because it can't be done.


Hmmm. The thing is, the ancestors of domesticated horse and cattle are extinct, so how do we know how docile they were ?
Also, there is some evidence pointing towards domesticated pigs being descended from European wild boar which are anything but docile.
This suggests that it was the knowledge on how to domesticate animals that was passed from people to people and not necessarily the domesticated animals themselves, but who knows. It was an awful long time ago.

[Bobby]

You make interesting points and I largely agree. However 'determinism' is a messy business in my view. There are numerous factors that come into play for a civilization to succeed or not.

You ask what if Mesopotamia had only dogs and squash? Well then mankind would not have settled there, or if they did they would have fared poorer than those who lived in an area with dogs, squash, and hot dogs! But of course this begs the question as to how people got to Mesopotamia, and how and why the others found tha land of the hot dogs. Decisions were made!

It is generally accepted that man started in Africa. Now mankind is found globally, everywhere. Obviously some people stayed in Africa, and they are still there. Those who migrated north to the Fertile Crescent found a land of plenty relatively speaking, thise who stayed behind remained in an inhospitable climate that prevented much interchange of ideas and thus growth. What of the DECISIONS of those who left? Diamond never delves here. Somebody in Africa, or some tribe, said 'this place sucks! Let's look for someplace better.' Those intrepid peoples who left found the Tigris and Euphrates and the rest is history.

My point is that mankind is able to seek out the best environments. He fights other men to keep hold of them, and he stays so long as the environment is conducive to his growth and prosperity. One would be hard pressed to find any people anywhere who have been there for all time. This is more the story of civilization than environmental deterministic approaches. Diamond 'blames' Western Civilization for a lot of badness in the book, that much I remember. He seems to blame them for winning and calls their success 'lucky'.

And of course there is the fact that Babylonian civilization was destroyed by the Persians, Greek Civilization by the Romans (and themselves), Egyptian Civilization by Alexander and so on and on. many of the great civilizations of all time disapreared from view, not because the environment betrayed them, but because their actions bsaed on their beliefs and ideas left them vulnerable OR because other peoples were enabled to destroy/change them.

Of course environement plays a role, I don't deny that. The Viking onslaught in Europe may have been caused by a burgeoning population in a period when the earth warmed dramatically and thus food production in Scandinavia boomed. The Viking population boomed with it and they expanded their areas of influence in rather interesting fashion. But this is one reason only. I don't buy deterministic approaches as I have probably said repeatedly, sorry. Instead I believe in a dialectic approach where all factors are taken into consideration to get as clear a picture as possible. You don't get a yes no answer from this approach but I think you get a clearer understanding of the complexities of human civilization and all the processes that effect it.

[Lucius]

So why did it take them so long to adopt the idea ?

I think they had to hit on the significance of the fact that the seeds are not all exactly the same size. So then they strain them out through a sieve and what's left in the basket gets planted next season(or maybe they pick out the big ones by hand, or whatever). To my humble way of thinking, that is the technique which signifies the arrival of agriculture, as opposed to a sort of hobby.

The arid climate of the "Fertile Crescent" made it easier to store the surplus and the seeds for planting next season. The storage of the surplus then gives rise to the breeding of dogs and cats, selecting for smaller and smaller size so as to serve as ratters. Otherwise, the rodent population will rapidly increase to accommodate the size of your surplus and you might as well be a hobbyist again.

Then they start breeding sheep and goats and horses and cattle and chickens and the rest is history.

[PADDYBOY]

I think they had to hit on the significance of the fact that the seeds are not all exactly the same size. So then they strain them out through a sieve and what's left in the basket gets planted next season(or maybe they pick out the big ones by hand, or whatever). To my humble way of thinking, that is the technique which signifies the arrival of agriculture, as opposed to a sort of hobby.


Thanks Lucius. Now, at risk of showing my ignorance here :o (which won't be the first time) What is the significance of big seeds and little seeds ? Do the big ones grow better, faster, truer, bigger......?
I really don't know.

[DesertPilot]

There have been quite a few points raised in the last posts -- too many for me to give credit where credit is due. Several observations:

1) Of the thousands of mammals and bird species, it's noteworthy that after tens of thousands of years of trying, we've only managed to domesticate a dozen or so. The others probably can't be domesticated. Their brains probably lack that design flaw that lets us short-circuit the 'Obey the Dominant Alpha Male' program so that they conclude we humans are the Ones Who Must Be Obeyed.

2) Agriculture is hard to get started. Yields for the precursors of modern crops pretty much suck. And their seeds, fruits, etc., ripen in ways that make them hard to gather and process. it appears that true agriculture was preceded by thousands of years of 'wild gardening', where hunter gatherers tended patches of wild plants they used to supplement food they obtained by hunting. And gathering. Which is why the earliest permanent settlements tend to be, not down in plains that are good for modern crops, but up in the hills where their inhabitants had access to a wide range of foods in case their crops failed. Again.

For a weirdly-written but perversely entertaining book on the subject with information Jared Diamond has not yet had a chance to pirate and claim as his own, check out 'After The Ice: A Global Human History, 20,000-5000 BC', by Steven Mithen. It's a well-researched and well-documented trove of useful information about the transition from the 'Zog hurled his spear at the large dangerous animal' time period to the 'Gorg and Zarah slaved away at their barren patch of earth from dawn till dusk, trying to scratch out a pathetic existence at the edge of starvation, all the while wonbdering why agriculture had seemed like such a good idea' era of human existance. But be warned... the writing is... very strange.

[PADDYBOY]

There have been quite a few points raised in the last posts -- too many for me to give credit where credit is due. Several observations:

1) Of the thousands of mammals and bird species, it's noteworthy that after tens of thousands of years of trying, we've only managed to domesticate a dozen or so. The others probably can't be domesticated. Their brains probably lack that design flaw that lets us short-circuit the 'Obey the Dominant Alpha Male' program so that they conclude we humans are the Ones Who Must Be Obeyed.



There's a Russian scientist by the name of Dmitri Belyaev, you may have heard of him, but for those who haven't....Back in the late 50s he did some research on one of those species that hasn't been domesticated because it didn't fit the criteria for domestication?
He was actually trying to figure out how wolves had been domesticated ?

Anyway, the species he used was the red fox or a variety of red fox called the silver fox which was used by the fur trade.
Believe it or not, by using selective breeding and only selecting the most docile members to breed from, he succeeded whithin ten generations (that's fox generations)
He produced fox that wagged their tails, licked their masters hands and oddly enough, started developing into different varieties from the original breeding stock...a bit like domesticated dogs

I would just add here, that although species such as zebra could be domesticated by modern man (if he wanted to) It was probably beyond the means of early man...

Btw Good post DesertPilot

[Bobby]

Yes, maybe it is true that Zebras cannot be domisticated, at least in ancient times. but that is besides the point I think. How did man find the right beasts to domesticate? They found them by leaving the land they were in for the proverbial greener pastures. There is a reward for the pioneering spirit, there is a penalty for those who cling to the status quo.

Those civilizations that domesticated the cattle, dogs, and other beasts did so because they could, But the only reason they could is because they had the intrepid spirit to change, adapt, and move forward. The people's in the Fertile Crescent weren't blown from Africa, they walked thousands of miles. Again, not luck, but reasoned choice. Domestication of animals was accomplished by the same type of peoples who left one place for a better place. It is the belief, the recognition, that life can be better that leads to such successes. It is not the choice of the climate or environment, at least not as the prime mover.

[Bobby]

Is Western success recent? Depends on the defintion of recent doesn't it? Of course the world is somewhat westernized now with Democratic and Republican institutions dominating the world and free market economies everywhere. These of course are Western concepts. I don't see the West falling as other civilizations did only because the lines between us and them are so blurred. Japan runs a free market economy with Democratic/Republican political structures. China too is now embracing free markets, although their political institutions are quite different.

We are all hooked together now, all nations. A recession in America means a recession worldwide and a recession in America can be caused by actions of other nations. China holds much of our debt. To sell off such debt at lowered prices would cause America to have to pay more for capital, and thus supressing the economy. China by selling these assets low would achieve less money than they had previously because with massive selling they would reduce the value. No nation can do anything economically without affecting other nations. Of course America drives all this with a gigantic economy which effects and affects other nations economies dramatically. This is why the health of the American economy is so important to the world.

So when we look in the past at declining or declined civilizations we see them in isolation. Today things are a bit different. Isolation is no more. We are all connected. One goes down and all others pay a price. An interesting and I think beneficial development.

[PADDYBOY]

Yes, maybe it is true that Zebras cannot be domisticated, at least in ancient times. but that is besides the point I think. How did man find the right beasts to domesticate? They found them by leaving the land they were in for the proverbial greener pastures. There is a reward for the pioneering spirit, there is a penalty for those who cling to the status quo.

Those civilizations that domesticated the cattle, dogs, and other beasts did so because they could, But the only reason they could is because they had the intrepid spirit to change, adapt, and move forward. The people's in the Fertile Crescent weren't blown from Africa, they walked thousands of miles. Again, not luck, but reasoned choice. Domestication of animals was accomplished by the same type of peoples who left one place for a better place. It is the belief, the recognition, that life can be better that leads to such successes. It is not the choice of the climate or environment, at least not as the prime mover.

Beside the point...Perhaps ? But so far, I've seen no evidence to support the idea that some animals were easier to domesticate than similar animals in other areas. Other than assumptions that if one group of people could do it and another group couldn't ? Then it must have been easy in one area and impossible in the other.
We don't know what temperament the ancestors of domesticated horse had coz they're extinct, cattle, the same, sheep ? well it seems they don't fit the criteria for domestication coz they spook easily, but, they flock, so that's alright ? We know that some domesticated pigs are descended from European wild boar, who don't fit the list. I've used Dmitri Belyaev's work to show how difficult it would have been to domesticate wolves. Ancient man wouldn't have had the large numbers held in captiviy that Dmitri had for his selection process.
I'm inclined to take the view that if one group of people went the extra mile and another group didn't ? It's probably because they had to rather than because they could. Why they had to is the bit I don't know.....

[Lucius]

Thanks Lucius. Now, at risk of showing my ignorance here :o (which won't be the first time) What is the significance of big seeds and little seeds ? Do the big ones grow better, faster, truer, bigger......?
I really don't know.

That's a very good question. I had assumed that planting only larger seeds would result in a greater percentage of large seeds in those plants which grew from only them. If I were a neo-lithic farmer, that's how I would reckon it out.

So I got on the google and came up with this (http://www.bioone.org/doi/abs/10.1614/WT-05-152R.1) -

"At the same time, wheat yield and economic returns were greater for wheat plants derived from large seed compared to those derived from small seed."

I think the size of the seed would also affect the success of germination in the first place.

I'm just a tree-skinner, not an agronomist, but I think if the first neolithic field were replanted every season with only the largest 3% of seed harvested, after a century one would notice an increase in yield per acre.

[DesertPilot]

There's a Russian scientist by the name of Dmitri Belyaev, you may have heard of him, but for those who haven't....

Thanks for the reference, Paddyboy. I vaguely remember hearing something about his research -- perhaps in some essay by Stephen J Gould or the like -- but I'd entirely forgotten his name. That is way useful information! I'll start tracking it down.

[Bobby]

Beside the point...Perhaps ? But so far, I've seen no evidence to support the idea that some animals were easier to domesticate than similar animals in other areas. Other than assumptions that if one group of people could do it and another group couldn't ? Then it must have been easy in one area and impossible in the other.
We don't know what temperament the ancestors of domesticated horse had coz they're extinct, cattle, the same, sheep ? well it seems they don't fit the criteria for domestication coz they spook easily, but, they flock, so that's alright ? We know that some domesticated pigs are descended from European wild boar, who don't fit the list. I've used Dmitri Belyaev's work to show how difficult it would have been to domesticate wolves. Ancient man wouldn't have had the large numbers held in captiviy that Dmitri had for his selection process.
I'm inclined to take the view that if one group of people went the extra mile and another group didn't ? It's probably because they had to rather than because they could. Why they had to is the bit I don't know.....

I don't mean to belittle the domestication point, in fact I agree with your analysis. I remember distinctly Diamond saying that BUffalo was non-domesticable for native Americans but of course this is not true. I believe with selective breeding and intensive training many, if not most animals can be domesticated. I've had a raccon as a pet, a vicious animal in nature. And how about Ferets? The pet du jour. In teh wild the feret, weasel families, are amongst the most vicious animals on earth. Bears are trained to ride motorcycles, elephants were ridden roughshod over the Romans by Hannibal, and on and on it goes.

I don't know that I would say those who domesticated 'had to', but I would say those who did prospered as a result.

[Wobomagonda]

paddy boy is right, domestication relies very little on locale, except in plants.

All animals can be domesticated, don't believe me? I've beed breeding spiders for about 5 years now, and I've bred the trapping instinct out of a common Brown Recluse Spider, he now eats lettuce and dead prey (spiders in the wild will never do this, they will die sooner), if that isn't domestication idk what is.

[Bobby]

That's a very good question. I had assumed that planting only larger seeds would result in a greater percentage of large seeds in those plants which grew from only them. If I were a neo-lithic farmer, that's how I would reckon it out.

So I got on the google and came up with this (http://www.bioone.org/doi/abs/10.1614/WT-05-152R.1) -

"At the same time, wheat yield and economic returns were greater for wheat plants derived from large seed compared to those derived from small seed."

I think the size of the seed would also affect the success of germination in the first place.

I'm just a tree-skinner, not an agronomist, but I think if the first neolithic field were replanted every season with only the largest 3% of seed harvested, after a century one would notice an increase in yield per acre.

Selective breeding of plants is what you are saying and it makes sense to me. I save my seeds from my veggie garden every fall, but I only save the seeds from the best fruit, the best plants. It's what my grandad taught me. Ignore the smaller fruits and plants and concentrate on the most productive. Over the years I have ended up with some extraordinary plants using this method. Those in antiquity that figued this out ran up the ladder of progress, those who didn't were left behind, or disapeared. It's Darwinist as hell!

[Wobomagonda]

yes, selective breeding in plants works well, provided you have enough healthy plants to harvest seeds from.

survival of the fittest doesn't really apply in humans, we have created our own rules for us. We put those who wouldn't normally survive in places like hospitals, wards, asylums, etc.

[DesertPilot]

yes, selective breeding in plants works well, provided you have enough healthy plants to harvest seeds from.

survival of the fittest doesn't really apply in humans, we have created our own rules for us. We put those who wouldn't normally survive in places like hospitals, wards, asylums, etc.

Very true, but fitness is a relative term. Perhaps they're fitter because they've more capable of winning the competition to get into a hospital, ward, asylum, or the like :)

Actually, this is a serious observation. What is fitness? Surely it depends on context. Early amphibians obviously lost the competition to survive in the ocean -- that's why they were forced to move onto the land. And some fat slob who lazes around the couch all day watching TV may well be more 'fit' to survive in modern civilization than some lean, agile, intelligent, and athletic hunter-gatherer who lacks the genetically-endowed skills to get a job to buy that couch and TV.

The biggest reason why evolution may have stopped for humans is that we interbreed so enthusiastically. It's been suggested that new species only develop when some small population is reproductively isolated after moving to a new environment. And modern humans are too randy to do that 'reproductively isolated' thing very well

[Wobomagonda]

my thoughts exactly

[PADDYBOY]

We've had one of those isolated breeding colonies here in Britain for quite a while now. They are so revered by the rest of the pouplation, that they are treated like Royalty....Actually they are Royalty....Did DesertPilot say "interbreeding" or "inbreeding" ?

[DesertPilot]

We've had one of those isolated breeding colonies here in Britain for quite a while now. They are so revered by the rest of the pouplation, that they are treated like Royalty....Actually they are Royalty....Did DesertPilot say "interbreeding" or "inbreeding" ?

It could be worse, Paddyboy! Think of those Hapsburgs. I've always imagined the noble families of late Medieval Europe as a bunch of wargammers playing some complicated strategic game. Some invested in armies. Others invested in economic development. But the Hapsburgs read the entire rulebook from cover to cover and noticed something the others had missed -- i.e. "Hey cool, check out Rule 247.113! If I sleep with someone, I get to keep their country!"

Like dinosaurs, they ruled the world. But like dinosaurs, they became extinct when their last surviving member, Maria Theresa of Austria, was killed by a giant asteroid in 1780...

[Gracchus]

survival of the fittest doesn't really apply in humans, we have created our own rules for us. We put those who wouldn't normally survive in places like hospitals, wards, asylums, etc.
Survival, in the evolutionary context, means more than long life. Survival means having descendents. Of course we've kicked most of the inmates out of the mental hospitals and asylums where very few if any had a chance to breed, but they usually have trouble finding sexual partners anyway.

:rolleyes:

[PADDYBOY]

Like dinosaurs, they ruled the world. But like dinosaurs, they became extinct when their last surviving member, Maria Theresa of Austria, was killed by a giant asteroid in 1780...

Nice ! :D

[AndrewRayGorman]

Too many posts for me to read over here. I am no scientist, as awesome as that would be. My guess is Darwin's theory of "Natural Selection" played at least some part in the death of these dinosaurs, if gradually.