Antartican organisms (extinct)

[griffon502]

Antartica was part of the Southern landmass, Gondwana, which also contained present-day India, Africa, South america, Australia and New Zealand. It was located in the tropics and gradually shifted southwards, until it reached its current position.

So the question is, what was the life like in Antactica?

I know only two terresrial plant species survived to the present-day, which are Antarctic hair grass and Antarctic pearlwort. But before it reached its current position it's obvious the life was much more abundant.

The biggest problem I think, is the fossils are now buried under tens of meters of ice blanket, so compared with other continents we know a lot less.

But anyway, tell me what you know about the Antartica life (land plant and animals) AFTER the extinction of dinosaurs, and BEFORE it reached its present southpole location. Thanks.

[j_sum1]

tens of metres -- meh. The ice blanket is up to 3km thick.
And there's your problem if you are putting together your ideas based on fossil evidence.

[coremelt]

Two percent of Atartica is ice free, mostly in the dry valleys and the fossil record has been extensively studied.

There was lush tropical forests in Antartica even when it was very close to its present position, during a period of elevated co2 levels.
http://www.bbc.co.uk/news/science-environment-12378934

[j_sum1]

2% isolated to a few specific areas isn't much of a sample space.
Not saying it is worthless, but there is a whole lot that is unknown.

[coremelt]

Originally Posted by j_sum1

2% isolated to a few specific areas isn't much of a sample space.
Not saying it is worthless, but there is a whole lot that is unknown.

There's ice free areas on the Antartica peninsula and bare rock exposed on many mountains in Antartica as well as in the dry valleys. Some more finds listed here:
http://news.nationalgeographic.com/n...olardinos.html

Sure if the whole continent was exposed you'd find a lot more but considering it was joined to Australia not that long ago, we have a pretty good idea that before that the the flora and fauna was very similar to Australias fossil record.

[griffon502]

Originally Posted by coremelt

There's ice free areas on the Antartica peninsula and bare rock exposed on many mountains in Antartica as well as in the dry valleys. Some more finds listed here:
http://news.nationalgeographic.com/n...olardinos.html

Sure if the whole continent was exposed you'd find a lot more but considering it was joined to Australia not that long ago, we have a pretty good idea that before that the the flora and fauna was very similar to Australias fossil record.

Are you saying that the land mammals in Antarctica were all marsupials? How diverse were they? Any fossils?

[Blake]

Originally Posted by coremelt

Sure if the whole continent was exposed you'd find a lot more but considering it was joined to Australia not that long ago, we have a pretty good idea that before that the the flora and fauna was very similar to Australias fossil record.

Antarctica split from Australia well before it split from South America, which is why the Eocene fossil record of Antarctica is highly similar to that of South America, and utterly unlike that of Australia. That's also why marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica.

Originally Posted by griffon502

Are you saying that the land mammals in Antarctica were all marsupials? How diverse were they? Any fossils?

They weren't all marsupials by any stretch. There were several different groups of marsupials, including opossums and the ancestors of Australia's marsupials. But there were also relatives of the armadillos and a several of the more bizarre South American hoofed animals as well.

Basically Antarctica seems to have had the same mammal suite as South America, though a little less diverse in species terms because it was so damn cold.

[Kamrusepas]

Looks like I'll have to be the first to say the obvious:

Great Old Ones.

[griffon502]

Originally Posted by Blake

Antarctica split from Australia well before it split from South America, which is why the Eocene fossil record of Antarctica is highly similar to that of South America, and utterly unlike that of Australia. That's also why marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica.



They weren't all marsupials by any stretch. There were several different groups of marsupials, including opossums and the ancestors of Australia's marsupials. But there were also relatives of the armadillos and a several of the more bizarre South American hoofed animals as well.

Basically Antarctica seems to have had the same mammal suite as South America, though a little less diverse in species terms because it was so damn cold.

Shame that the placentals never made it to Australia before the human influence except some bats. Just a single semi-domesticted dog (dingo) caused mass extinction of marsupials, and made the Tasmanian tigers extinct on mainland, that's just an example on how inefficient the marsupials are when it comes to best-utilize the available resources.

Marsupials simply are not competitive compared to placentals. One example is how they utterly failed to effectively colonize the mountain ranges in Australia, while in other parts of the world where the condition on the mountain terrain is much harsher, the placentals still thrive (e.g. goat-antelope species, camellids, hyrax species, marmot species, carnivores such as puma and snow leopard).

From what you said though, it appears that the Southern Ungulates, are even less competitive, because they can't even compete against the marsupials in Australia and became extinct there. No wonder they got wiped out so quickly when the true ungulates from North America arrived with the land bridge.

[Blake]

Originally Posted by griffon502

Shame that the placentals never made it to Australia before the human influence except some bats.

1) Placentals arrived in Australia around 10 million years before the marsupials. They just didn't arrive from South America. They were never common and they later became extinct.

2) Before humans arrived Australia had equal numbers of of placental mammals andd marsupials, just as it does today. Far from "some bats" Australia had huge numbers of species of bats and rodents.

Just a single semi-domesticted dog (dingo) caused mass extinction of marsupials, and made the Tasmanian tigers extinct on mainland...

No, it didn't. Not only not a mass extinction, there is not a single species extinction that can be clearly attributed to the dingo. Maybe, just maybe, they contributed to the extinction of the Thylacine or Devil from the mainland, but the majority of ecologists accept that at worst they contributed to their demise by assisting human hunting.

So that's a grand total of two species at the most extreme. Not really amass extinction.

.. that's just an example on how inefficient the marsupials are when it comes to best-utilize the available resources.

No, it's an example of gross ignorance of the facts.

I know the Victorian idea that marsupials are somehow inferior has held on longer than the idea that Black people are somehow inferior, but the two ideas have exactly the same roots and they both have the exact same evidence: none.

Marsupials are objectively much more efficient than placentals when it comes to utilising resources. A kangaroo will live on about 75% of the amount of grass needed to feed an identically sized deer or antelope. A quoll will survive on just half the number of kills that would to feed a fox. An opossum needs about 2/3 the number of calories of a raccoon.

Placental mammals are profligate energy users and incredibly inefficient. They are essential animal weeds.

Marsupials simply are not competitive compared to placentals.

In the real world we have three natural experiments: Australia, South America./Antarctica and the rest of the planet. In Australia marsupials dominated and placentals became completely extinct extinct. In south America, marsupials completely dominated the carnivore/omnivore niches and placentals were restricted to herbivory. In the rest of the world placentals became completely extinct.

IOW we have seen the results of three natural experiments and the results are a perfect random spread.

In terms of artificial experiments, we simply have to consider that for over 100 years there were attempts to introduce over 700 placental mammals species to Australia. A grand total of 12 managed to survive in the face of competition form the native marsupials.

There is no justification of any sort for a claim that marsupials are not competitive with placentals.

One example is how they utterly failed to effectively colonize the mountain ranges in Australia, while in other parts of the world where the condition on the mountain terrain is much harsher, the placentals still thrive (e.g. goat-antelope species, camellids, hyrax species, marmot species, carnivores such as puma and snow leopard).

WTF?

Firstly, what mountain ranges in Australia?

Australia is the flattest continent on the planet. Mainland Australia only has one mountain range that is even detectable to the naked eye: the Great Divide. Even that disappears into a gentle slope for large parts of its length. There are a few isolated ranges of hills in the 400-1500m range, but they are insignificant geographically. Australia is incredibly flat.


Secondly, and probably because of this, Australia is home to the greatest diversity of mountain adapted mammals in the world. There are over 20 different species of rock wallabies alone, compared to the single species of Mountain goat found in North America or the ten species of mountain ungulate found in Asia.

I have no idea where you are getting this stuff from, but it is utterly incorrect. At best it is outdated by 50 years, but much of it has simply never been accepted by any ecologist anywhere

From what you said though, it appears that the Southern Ungulates, are even less competitive, because they can't even compete against the marsupials in Australia and became extinct there.

Ahh, no. What I said was (and I quote) "marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica". Ungulates could hardly become extinct in Australia when they never made it to Australia.

But that is rather beside the point, because your whole thesis that marsupials are somehow uncompetitive has no basis in reality.

[griffon502]

edited, retarded enter button

[Colibri]

Originally Posted by griffon502

From what you said though, it appears that the Southern Ungulates, are even less competitive, because they can't even compete against the marsupials in Australia and became extinct there. No wonder they got wiped out so quickly when the true ungulates from North America arrived with the land bridge.

The southern ungulates (toxodonts and liptoterns) were not "wiped out so quickly" after the Panama land bridge formed. At least some of them co-existed with the northern ungulates for three million years or more. Toxodonts moved north as far a Mexico. The last surviving litoptern, Macrauchenia, became extinct only about 10,000 years ago. Both may have fallen victim to paleoindian hunters rather than competition with northern ungulates.

It's not clear that the decline of the marsupial carnivores of South America was directly due to competition with placental carnivores; they were already extinct before most of the placentals arrived from the north. While they may have suffered from competition with members of the raccoon family that arrived before the land bridge was complete, they also had to compete with the phorusrhacids, large flightless carnivorous birds, as well as opossums, which were fellow marsupials. See here.

[griffon502]

Ok Blake, it seems the ecological myths, combined with a false sense of Australian nationalism, have clearly clouded your judgement and made you unable to make objective judgement. You are simply biased against placentals. I tell you what, I care about the truths and the truths only.

1) Placentals arrived in Australia around 10 million years before the marsupials. They just didn't arrive from South America. They were never common and they later became extinct.

All this "evidence", came from a SINGLE teeth. It is not substaintial.

2) Before humans arrived Australia had equal numbers of of placental mammals andd marsupials, just as it does today. Far from "some bats" Australia had huge numbers of species of bats and rodents.

Australia had only 2 genera of bats, that is hardly "huge number".

And what the heck is the "equal" number you talking about? Species? Quantity? Without defining what "number" you are refering to the discussion would be pointless. You don't seem to be able to talk in more scientific terms.

No, it didn't. Not only not a mass extinction, there is not a single species extinction that can be clearly attributed to the dingo. Maybe, just maybe, they contributed to the extinction of the Thylacine or Devil from the mainland, but the majority of ecologists accept that at worst they contributed to their demise by assisting human hunting.

So that's a grand total of two species at the most extreme. Not really amass extinction.

In your mind, the imaginary early placentals got extinct due to over-competition from early marsupials, where is YOUR evidence then? How can you clearly contribute their disappearence to the marsupials? NONE. It is so obvious that you are biased against placentals.

No, it's an example of gross ignorance of the facts.

I know the Victorian idea that marsupials are somehow inferior has held on longer than the idea that Black people are somehow inferior, but the two ideas have exactly the same roots and they both have the exact same evidence: none.

Typical liberal/socialist mindset. Turning every debate into some politcal-correctness issue. Ever heard of Reductio ad Hitlerum? That's excactly where your
"arguments" are coming to.

Marsupials are objectively much more efficient than placentals when it comes to utilising resources. A kangaroo will live on about 75% of the amount of grass needed to feed an identically sized deer or antelope. A quoll will survive on just half the number of kills that would to feed a fox. An opossum needs about 2/3 the number of calories of a raccoon.

Oh really. How come rabbits became so rampant. How come camels, water bufflos, dingos, foxes and so on became so widespread to the point the Australian government had to intentionally try to exterminate them?

I tell you what, it is well-known that ruminants are the most efficient herbivores due to their ability of ruminating.

And deers DON'T feed on grass like kangaroos. Deers are mostly BROWSERS, not grazers. but clearly you have no idea such distinction even exists, judging by the fact you lumped them together.

Placental mammals are profligate energy users and incredibly inefficient. They are essential animal weeds.

Totally laugable eco-bargage, fed by marxist-eco professors. Just because placental MIGHT tend to use more energy does not make them inefficient. By your logic reptiles are more efficient as they use even less energy. You clearly do not understand what "efficiency" is about.

And calling placentals "weeds"? How about you end your own life, you are placental yourself hence by definition you are weeds. And don't eat beef, pork, lamb, milk any more. They are weeds.

In the real world we have three natural experiments: Australia, South America./Antarctica and the rest of the planet. In Australia marsupials dominated and placentals became completely extinct extinct. In south America, marsupials completely dominated the carnivore/omnivore niches and placentals were restricted to herbivory. In the rest of the world placentals became completely extinct.

Totally wrong. You have absolutely NO IDEA about the natural world.

Seriously, since when did jaguar, mountain lion, tapir, racoon, coyote, deers, rodents and so on became marsupials? In SA, after the land bridge connected NA with SA, all marsupials got wiped out by placentals except the small-sized possum species.

That was what would happen to Australia, if a similair event happened.

In the rest of the world placentals became completely extinct

I assume you meant marsupials. Otherwise this would be the most stupid statement I've seen in this forum.

IOW we have seen the results of three natural experiments and the results are a perfect random spread.

Only in your imaginary marsupial utopia, is it a perfect random spread. It is obvious that on all landmasses where marsupials and placentals compete, the marsupials got nearly wiped out, and in case they survives they only occupy very limited niches.

In terms of artificial experiments, we simply have to consider that for over 100 years there were attempts to introduce over 700 placental mammals species to Australia. A grand total of 12 managed to survive in the face of competition form the native marsupials.

Non-sense. There have never been so much introductions, and even if there were, most were very small-scale done by common people with little skills, and most were just for destination such as zoos and carnivals, hardly an "introduction" intended to establish viable, long-term population in Australia.

And for the placentals that are present, they are remarkly successful. This is agreed upon by your fellow "ecologists" which is why they are so eager to exterminate them, because they think they out-compete and out-predate on the marsupials.

WTF?

Firstly, what mountain ranges in Australia?

Australia is the flattest continent on the planet. Mainland Australia only has one mountain range that is even detectable to the naked eye: the Great Divide. Even that disappears into a gentle slope for large parts of its length. There are a few isolated ranges of hills in the 400-1500m range, but they are insignificant geographically. Australia is incredibly flat.


Secondly, and probably because of this, Australia is home to the greatest diversity of mountain adapted mammals in the world. There are over 20 different species of rock wallabies alone, compared to the single species of Mountain goat found in North America or the ten species of mountain ungulate found in Asia.

The wallabies are hardly adapted to mountain life, compared to the mountain animals in other parts of the world. The environment they live in would be considered paradise for these mountain placentals in the outside world.

And rock-wallabies are now declining due to competion from goats, sheeps,and rabbbits. This tells you a lot.

I have no idea where you are getting this stuff from, but it is utterly incorrect. At best it is outdated by 50 years, but much of it has simply never been accepted by any ecologist anywhere

I reach my conclusion through independent and logical thinking, rather than taking whatever garbage from the eco-marxist professors. And I have just shown you how incorrect you are.

Ahh, no. What I said was (and I quote) "marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica". Ungulates could hardly become extinct in Australia when they never made it to Australia.

You have no idea what I was talking about, do you? First, this reply is irrevelant to my point, you are replying to something I never meant because you did not understand what I said. Second, you clearly have absolutely no idea what Southern Ungulates are, do some research before you speak.

[griffon502]

Originally Posted by Colibri

It's not clear that the decline of the marsupial carnivores of South America was directly due to competition with placental carnivores; they were already extinct before most of the placentals arrived from the north. While they may have suffered from competition with members of the raccoon family that arrived before the land bridge was complete, they also had to compete with the phorusrhacids, large flightless carnivorous birds, as well as opossums, which were fellow marsupials.

The presence of large flightly carnovorous birds might as well be an indicator of the inefficiency of the marsupial carnivores. They became extinct shortly after the arrival of plancetal carnivores such as the true sabre-toothed cats.

Gastornis, another genus of large, carnivorous birds, was apex predators in late Paleocene and Eocene in Europe and North America. But they went extinct when mamallians began to out-compete them.

Taking from wikipedia.

The mid-Eocene saw the rise of large creodont and mesonychid predators to ecological prominence in Eurasia and North America; the appearance of these new predators coincides with the decline of Gastornis and its relatives. This was possibly due to an increased tendency of mammalian predators to hunt together in packs (prevalent especially in hyaenodont creodonts). The fact that no birds appear to have ever weighed much more than half a metric ton suggests that they were restricted in their ability to evolve to larger and larger sizes, and thus in their ability to out-evolve apex predators by sheer bulk as mammals are often able to do (see Cope's Rule).

http://en.wikipedia.org/wiki/Gastornis

The conclusion is, placental carnovivores were able to evolve to out-compete the large carnivorous birds. They first managed to do that in Europe and NA, then when the land bridge is formed, they did the same to the SA carnivous birds. Only this time it was even quicker because the mammal carnivores did not have to co-evolve with the SA birds to out-compete them.

On the other hand, the marsupials failed to out-compete against the terror birds. The terror bird continued existence only proved that marsupials were inefficient, in-competent predators, compared with placentals.

[griffon502]

I just want to add a point. It's not just the mountain species, or the carnivores, even the ant-eating marsupials are inefficient compared to the placentals.

The numbats simply "suck" compared to the placental ant-eaters. They have the least skills when it comes to survival and ant-eating. They fail in almost EVERY category. Only "advantage" is maybe they look the cutest ant-eater so I would have no problem owning one as a pet.

1. ability of foraging
The numbats, according to wiki, do not have claws that are "strong enough to get at termites inside their concrete-like mound, and so must wait until the termites are active". Almost all other ant-eaters do.

Pangolins, aardvak, and Amercain ant-eaters, all powerful enough to do that.

2. protection against predator

Numbats are suffering because of RED FOXES, I mean, seriously, red foxes.... small-sized canine species have never been a problem for other ant-eaters.

In addition, numbats are UN-ARMORED, and cannot dig quickly.

Heck, even the Echidna got spines which protect them from predators, and they are mono-tremes.......

It's pathetic that numbats are only able to survive because of protection from human.

[Colibri]

Originally Posted by griffon502

The presence of large flightly carnovorous birds might as well be an indicator of the inefficiency of the marsupial carnivores. They became extinct shortly after the arrival of plancetal carnivores such as the true sabre-toothed cats.

Cite? The Borhyaenidae is generally considered to range to about 5 million years ago, that is, before the Panama land bridge became complete and before most placental carnivores reached South America. Smilodon originated about 2.5 million years ago. I am not aware that any other sabre-toothed genera reached South America.

Gastornis, another genus of large, carnivorous birds, was apex predators in late Paleocene and Eocene in Europe and North America. But they went extinct when mamallians began to out-compete them.

Some Phorusrhacids were able to compete with placental carnivores, for example Titanis of Florida, which coexisted with them for a good 3 million years.

The conclusion is, placental carnovivores were able to evolve to out-compete the large carnivorous birds. They first managed to do that in Europe and NA, then when the land bridge is formed, they did the same to the SA carnivous birds. Only this time it was even quicker because the mammal carnivores did not have to co-evolve with the SA birds to out-compete them.

On the other hand, the marsupials failed to out-compete against the terror birds. The terror bird continued existence only proved that marsupials were inefficient, in-competent predators, compared with placentals.

This is a very simplistic view. There is no real evidence that the South American carnivores became extinct because of competition by placentals. As I said, they declined long before major carnivore groups even reached South America.

[griffon502]

I found a related discussion here:

http://ask.metafilter.com/121362/Why-do-placentals-win

Here are some important posts supporting my opnion:

Every time bioenergy is converted to edible matter and then eaten and digested, there is a huge energy loss. For a given mass of plant matter- by the time it winds up as blood glucose in a first order consumer - perhaps 80% of the energy the plant had used is gone. When that herbivore winds up in the blood of its predator, there has been a similar energy loss.

The production of marsupial milk is bioenergetically costly, as is the digestion of it within the fetus' belly. Conversely, a placental mother wastes no energy passing nutrients to baby. All other things being exactly equal, placentals will displace marsupials in short order as has been demonstrated by all placental imports to Australia conducted by people.

YIFIAABE (yes, in fact I am a behavioral ecologist).

Ironmouth, while Chocolate Pickle did indeed use the term "superior", the original phrasing was "outcompete" - and it would be hard to argue that placental mammals didn't outcompete marsupials on 6/7 continents.

We do not know what would happen if large numbers of animals from each group were to compete with one another.

We do. It was during the Cenozoic/Pleistocene changeover. Marsupials were displaced from almost all ecological niches by placentals, everywhere they coexisted.

[griffon502]

Originally Posted by Colibri

This is a very simplistic view. There is no real evidence that the South American carnivores became extinct because of competition by placentals. As I said, they declined long before major carnivore groups even reached South America.

How do you know? Moreover, even if it did happen, the placentals did not seem to be affected much, which in turn would suggest they were more adaptable.

What I think is, marsupials and placentals lived alongside with each other for millions of years during the dinosaur age. But once the dinosaurs were gone, the mammals were able to diversify quickly, and the placental were simply superior to marsupials and replaced them everywhere except isolated places like SA and Australia, and the marsupials in SA got wiped out when the placentals arrived.

The earliest marsupial fossil is found in China. The second oldest is from Mongolia.
http://news.nationalgeographic.com/n...marsupial.html

[Colibri]

That last comment [in post #17] is incorrect. You can't consider that there are 7 independent "experiments," but as Blake says, only three. Europe/Asia/Africa/North America have been effectively one land mass for most of the Cenozoic (the "World Continent", while Australia and South America were isolated island continents. Placentals dominated the World Continent, marsupials Australia, and South America had marsupial carnivores and placental herbivores. (We don't know much about Antarctica.)

If there is a competitive advantage, it is between animals that have evolved on larger land masses have an advantage over those from smaller landmasses. If animals from the World Continent have an advantage over those from the island continents, it's likely due to the fact that they come from a larger land mass.

[Colibri]

Originally Posted by griffon502

How do you know? Moreover, even if it did happen, the placentals did not seem to be affected much, which in turn would suggest they were more adaptable.

How do you know? Like I said, your view is largely speculation and is not strongly supported by any real evidence.

Originally Posted by griffon502

the marsupials in SA got wiped out when the placentals arrived.

As I said, this is simply incorrect. Stop repeating it unless you can produce some evidence that it's actually true.

First of all, marsupials did not get "wiped out." Opossums are diverse and widespread in the Americas, with over 100 species in the Americas in various ecological niches, and one is even common in North America.

Second, the marsupial carnivores in South America became extinct well before the arrival of most placental carnivores, so their demise can't be attributed to that.

[griffon502]

Originally Posted by Colibri

That last comment [in post #17] is incorrect. You can't consider that there are 7 independent "experiments," but as Blake says, only three. Europe/Asia/Africa/North America have been effectively one land mass for most of the Cenozoic (the "World Continent", while Australia and South America were isolated island continents. Placentals dominated the World Continent, marsupials Australia, and South America had marsupial carnivores and placental herbivores. (We don't know much about Antarctica.)

If there is a competitive advantage, it is between animals that have evolved on larger land masses have an advantage over those from smaller landmasses. If animals from the World Continent have an advantage over those from the island continents, it's likely due to the fact that they come from a larger land mass.

You fail to identify any mechanism.

It is obvious when you compare animal to animal. I've already illustrated the numbat example pretty well. And I also pointed out how ruminants are more efficient than kangaroos.

Your larger landmass point is without evidence, and pure speculation.

[Mewl Dear]

Originally Posted by Kamrusepas

Looks like I'll have to be the first to say the obvious:

Great Old Ones.

What does this even mean.
Nevermind if you can add nothing, stay out and I will too.

[griffon502]

I just thought of something new, related to what Blake said.

Blake and his marxist-eco professors or whatever, claim that placental animals somehow "wastes" more energy than marsupials.

First, I am not sure about the validity of that claim. Modern ecologists, influenced by marxists, do everything to demonize so-called "non-native" species.

Second, is what I am trying to present now. That is, they are ignorant of what energy is. If these so-called "ecologists" actually understand the physics taught during highschool, they might not be quick to invent such myth as "wasting energy".

Why? Because basic physics tells us, energy never disappear. They merely transform into another form. Assuming the claim that placentals somehow consume more energy than marsupials, it simply means they are more efficient energy users.

Almost all energy of an organism ultimately comes from the sun. When the sun shines, the plants convert solar energy into chemical energy via photosynthesis. Then they are eaten by herbivores which consumes its own chemical energy to obtain more chemical energy from plant matters, and they are in turn eaten by carnivores who spend chemical energy in pursuit of more chemical energy from the meat of the herbivores.

Therefore, energy is always there to take, but taking them require energy itself, so different organisms spend different amount of energy in order to obtain more energy.

For instance, areptiles have low energy requirement compared to . They are cold-blooded (i.e. do not need energy-expensive thermoregulation), so they can require less energy to survive because their energy expenture is low. A nile crocodile can survive months without food while a lion would turned into a skeleton already.

But this is done at a cost. Though reptiles do not need expensive thermoregulation, it also means they are less adaptable at colder climates than mammals. Mammals can survive in the arctic by converting chemical energy into heat energy, aided by thick coat or fat. Reptiles just freeze to death.

Therefore whether a species is more "advanced" might be indicated by the level of energy it could utilize. Humans, for example, have become the master of energy, to a level not a single other species of organism have ever achieved. And within human itself such distinction is still valid. More advanced people are able to utilize more energy than the less advanced. While people in the civilized world are able to obtain chemical energy from food in a large scale cheaply, exploiting energy from sources such as electricity, and even "wasting" massive energy by burning them in a few seconds in rocket-fuels for some of the fortunate ones for space tourism, the less advanced still rely on charcoals and have to spend their own energy just to carry water from the rivers because there is no running water.

[MrDibble]

Originally Posted by Kamrusepas

Looks like I'll have to be the first to say the obvious:

Great Old Ones.

I think you mean Elder Things

[Frodo]

Tekeli-li! Tekeli-li!

[Polycarp]

Originally Posted by Mewl Dear

What does this even mean.
Nevermind if you can add nothing, stay out and I will too.

The Great Old Ones were the malign Elder Gods who, among other things, inhabited Antarctica in Days Of Yore (and Gore and Vore) in the Chulhu Mythos of H.P. Lovecraft and his circle of horror writers. It was in the nature of a recondite witticism.

[Colibri]

Originally Posted by griffon502

You fail to identify any mechanism.

This is a fairly well known hypothesis. The mechanism is that animals on larger land masses are confronted by competition from a larger number of species, and thus have their competitive capacity honed.

Here's some detailed discussion of the hypothesis.

It is obvious when you compare animal to animal. I've already illustrated the numbat example pretty well. And I also pointed out how ruminants are more efficient than kangaroos.

No, it's not particularly obvious. Cherry-picking examples is not evidence.

Your larger landmass point is without evidence, and pure speculation.

There's as much evidence for it as your speculation.

[griffon502]

Originally Posted by Colibri

This is a fairly well known hypothesis. The mechanism is that animals on larger land masses are confronted by competition from a larger number of species, and thus have their competitive capacity honed.

Here's some detailed discussion of the hypothesis.



No, it's not particularly obvious. Cherry-picking examples is not evidence.



There's as much evidence for it as your speculation.

How's that cherry-picking? Seems to me you are ignoring the overwelming evidence.

And for the theory, I know it very well. However you applied it wrong, which is why you came to the wrong conclusion.

[Filbert]

Cane toads are a major pest in Australia, so I take it this means anurans are superior lifeforms as well?

What introduced species do well is really not an indicator of some imagined subclass superiority- hell, New Zealand Flatworms are becoming a serious problem in the UK, and they're flatworms. All it can possibly mean is that that single species has found a niche where it is, at least in the short term, outcompeting one or more native species, which can take place for a variety of reasons, including being more adapted to the environmental change being brought about by humans. If every time a new group came along it wiped out the previous donimant group, we wouldn't still have birds, reptiles, amphibians, insects...

Oh, and for someone who claims to be only concerned with the facts, comments like:

Originally Posted by griffon502

Shame that the placentals never made it to Australia before the human influence except some bats. Just a single semi-domesticted dog (dingo) caused mass extinction of marsupials, and made the Tasmanian tigers extinct on mainland, that's just an example on how inefficient the marsupials are when it comes to best-utilize the available resources.

don't half make it sound like you have some odd personal grudge against marsupials.

Ever considered campaigning against monotremes instead?

[Colibri]

Originally Posted by griffon502

How's that cherry-picking? Seems to me you are ignoring the overwelming evidence.

You haven't presented any overwhelming evidence. You've presented a couple of examples. That's cherry-picking.

And for the theory, I know it very well.

If you had heard of it, then why did you ask me to identify the mechanism?

However you applied it wrong, which is why you came to the wrong conclusion.

Whatever are you talking about? Please explain how I applied it wrong. And how do you know your conclusion is right and mine is wrong, exactly?

[griffon502]

Just found more evidence of the inefficiency of the marsupials

It turned out that the top apex predator of marsupials in modern times, the tasmanian tiger, was totally incompetent, compared to placental equivalents.

From wiki:

"A 2011 study by the University of New South Wales using advanced computer modelling indicated that the thylacine had surprisingly feeble jaws. Animals usually take prey close to their own body size, but an adult thylacine of around 30 kilograms (66 lb) was found to be incapable of handling prey much larger than 5 kilograms (11 lb). Researchers believe thylacines only ate small animals such as bandicoots and possums, putting them into direct competition with the Tasmanian devil and the Tiger Quoll. Such specialisation probably made the thylacine susceptible to small disturbances to the ecosystem.[31][53]"

I mean seriously, how pathetic, a marsupial as large as the wolf, can only handle such small preys. NOW THIS *IS* inefficiency, or even inferiority, compared to placentals. You simply cannot deny it.

[Oldeb]

Originally Posted by griffon502

I mean seriously, how pathetic, a marsupial as large as the wolf, can only handle such small preys. NOW THIS *IS* inefficiency, or even inferiority, compared to placentals. You simply cannot deny it.

I don't understand how you're defining inefficiency. Predator/Prey size relationship seems an extremely bizarre definition. By that token the baleen whales (which include nine of the ten largest mammals) are vastly inferior to anything that has ever lived. For terrestrial mammals the Giant Anteater grows to more than twice the size of the Thylacine (up to 7 ft and 140 pounds) yet eats only insects as it lacks teeth. Does that make it horrible as well?

It sounds like existing on a diet of smaller than expected prey would relate first to Blake's point about metabolic efficiency being greater in marsupials and then to Colbri's point about specialization and lack of competition leading to animals that fair poorly when introduced to new species.

[Colibri]

Originally Posted by griffon502

I mean seriously, how pathetic, a marsupial as large as the wolf, can only handle such small preys. NOW THIS *IS* inefficiency, or even inferiority, compared to placentals. You simply cannot deny it.

On the other hand, according to Wiki the recently extinct Thylacoleo was the most remarkable mammalian carnivore of all time:

Pound for pound, Thylacoleo carnifex had the strongest bite of any mammal species living or extinct; a 100 kg (220 lb) T. carnifex had a bite comparable to that of a 250 kg (550 lb) African Lion[1] and is thought to have hunted large animals such as Diprotodon spp. and giant kangaroos. It also had extremely strong forelimbs, with retractable catlike claws, a trait previously unseen in marsupials. Thylacoleo also possessed enormous hooded claws set on large semi-opposable thumbs, which were used to capture and disembowel prey. The long muscular tail was similar to that of a kangaroo. Specialized tail bones called chevrons allowed the animal to tripod itself, and freed the front legs for slashing and grasping.[2]
Its strong forelimbs, retracting claws and incredibly powerful jaws mean that it may have been possible for Thylacoleo to climb trees and perhaps to carry carcasses to keep the kill for itself (similar to the leopard today). Due to its unique predatory morphology, scientists repeatedly claim Thylacoleo to be the most specialized mammalian carnivore of all time.[3]

By your own criteria, this means that marsupials must be superior to placentals.

Note that the Thylacoleo probably became extinct due to the arrival of humans in Australia, not because of any competition with placentals.

[coremelt]

So back to the OP. is it still the case that no true mammal fossils have been found in Antarctica? So far both Marsupial and proto-mammalian fossils have been found but no modern mammals?

Is that correct?

[Sailboat]

Originally Posted by Colibri

Note that the Thylacoleo probably became extinct due to the arrival of humans in Australia, not because of any competition with placentals.

Nitpick: aren't humans placental?

[Sailboat]

Originally Posted by griffon502

I mean seriously, how pathetic, a marsupial as large as the wolf, can only handle such small preys. NOW THIS *IS* inefficiency, or even inferiority, compared to placentals. You simply cannot deny it.

Why the terminology of value judgment? What's "pathetic" about an animal's diet?

[DrDeth]

Originally Posted by Blake

In the real world we have three natural experiments: Australia, South America./Antarctica and the rest of the planet. In Australia marsupials dominated and placentals became completely extinct extinct. In south America, marsupials completely dominated the carnivore/omnivore niches and placentals were restricted to herbivory. In the rest of the world placentals became completely extinct.

I think you meant to say "In the rest of the world marsupials became completely extinct."

Other than that, I agree with you nearly 100%.

[griffon502]

More evidence supporting my theory that the relatively success of South American terror birds before the Great American Exchange, was due to the inefficiency of the marsupials.



from wiki:

Metatherians were the only South American mammals to specialize as carnivores; their relative inefficiency created openings for nonmammalian predators to play more prominent roles than usual (similar to the situation in Australia).

http://en.wikipedia.org/wiki/Great_American_Interchange

Note the Metatherians had been regarded as marsupials, but recently it has been seperated from it but still regarded as being very closely related. Also note that it was the only carnivorous mammal in SA before the arrival of the placental carnivores with the Great Amercan Exchange, meaning the metatherians out-competed the marsupials yet got defeated by the placentals.

[MrDibble]

Dude, let it go.

[griffon502]

This slide below just freaking NAILED IT. Marsupials *are* inferior. They deserve to be replaced by placentals. Australia should stop its overly-protective policies. Heck, you can't even own a freaking HAMSTER because it is feared that these "foreign" animals would "devastate" the marsupials. LOL. Bring it on. No mercy for the losers. You don't deserve tears when you lose the evolutionary race.

http://www.google.com/url?sa=t&rct=j...VI7O5W1QShFF_Q

Some important parts in the slide:

II. Are marsupials inferior?

A. Lines of reasoning that they are:

1. Less diversity of habitat types
2. Less diversity of locomotion
3. Less diversity of foraging
4. No really big marsupials
5. Social organization is less complex
6. Not as speciose
7. Most diverse and numerous in Australia, where there is negligible competition with eutherians

B. Is the competitive disadvantage the result of their mode of reproduction?

Maybe. Their mode of reproduction limits the environments in which they can live.

Maybe not. Other factors include:
Cerebral cortex of marsupials is smaller and develops more slowly
Learning and behavioral flexibility is less developed in marsupials.
Behavior is less diverse.
They have a small number of chromosomes, which may make them less evolutionarily flexible.
Their reproductive rate is lower.


C. An alternate view is that marsupials are not necessarily at a competitive disadvantage in all circumstances. Possible advantages of a marsupial reproductive stratgey include:

Low energy requirements, spread out of a long period of time
Can quickly replace lost young

[DrDeth]

Originally Posted by griffon502

This slide below just freaking NAILED IT. Marsupials *are* inferior. They deserve to be replaced by placentals. Australia should stop its overly-protective policies. Heck, you can't even own a freaking HAMSTER because it is feared that these "foreign" animals would "devastate" the marsupials. LOL. Bring it on. No mercy for the losers. You don't deserve tears when you lose the evolutionary race.

http://www.google.com/url?sa=t&rct=j...VI7O5W1QShFF_Q

Some important parts in the slide:

II. Are marsupials inferior?

A. Lines of reasoning that they are:

1. Less diversity of habitat types
2. Less diversity of locomotion
3. Less diversity of foraging
4. No really big marsupials
5. Social organization is less complex
6. Not as speciose
7. Most diverse and numerous in Australia, where there is negligible competition with eutherians

B. Is the competitive disadvantage the result of their mode of reproduction?

Maybe. Their mode of reproduction limits the environments in which they can live.

Maybe not. Other factors include:
Cerebral cortex of marsupials is smaller and develops more slowly
Learning and behavioral flexibility is less developed in marsupials.
Behavior is less diverse.
They have a small number of chromosomes, which may make them less evolutionarily flexible.
Their reproductive rate is lower.


C. An alternate view is that marsupials are not necessarily at a competitive disadvantage in all circumstances. Possible advantages of a marsupial reproductive stratgey include:

Low energy requirements, spread out of a long period of time
Can quickly replace lost young

Back in the old days, yes, they used to have these neat charts which showed Marsupials at the bottom, and us Humans at the top. This is sooooo outdated.

Look, yes, in many cases a marsupial will be pushed out of it's niche by a placental mammal, but in many cases if you have a insular population, many species will be pushed out by more competive outside species.

In many niches the marsupial does extremely well- witness the Opossum.

So, there's no "inferior". It's whatever does best in that niche.

[griffon502]

Originally Posted by DrDeth

Back in the old days, yes, they used to have these neat charts which showed Marsupials at the bottom, and us Humans at the top. This is sooooo outdated.

Look, yes, in many cases a marsupial will be pushed out of it's niche by a placental mammal, but in many cases if you have a insular population, many species will be pushed out by more competive outside species.

In many niches the marsupial does extremely well- witness the Opossum.

So, there's no "inferior". It's whatever does best in that niche.

Still in denial, aren't you? Doing best in niche? What niche does not the marsupials occupy that cannot be filled by placentals? On the other hand, there are so many niches that placentals fill that cannot be filled by marsupials.

Did marsupials develop their own fully-aquatic animals, comparable to the whales and dolphins?

how about a little less aquatic, comparable to seals, sea lions, walruses etc.?

now how about semi-aquatic, comparable to otters, capybaras, beavers?

how about flying ones comparable to the placental bats?

how about large-sized species truly adapted to deserts, such as camels, gemsbok, addax?

There is no doubt that species are to fill the niches, however, which niches that marsupials can fill but placentals cannot? Name one.

It's like real life. Burger flippers can be good at their niches, are they not? But a middle-class worker can also be made to do such job and be good at it after some time, but a burger flipper would be unable to do the middle-class job as well as that worker. That's why a burger flipper earns minimum wage.

[Anise]

Apparently, nobody else had the same reaction that I did...

Dinosaurs looking up at the pretty sky! OO SHINY!!!

That has been my serious scientific input for the day.

[Capt Kirk]

Originally Posted by griffon502

Still in denial, aren't you? Doing best in niche? What niche does not the marsupials occupy that cannot be filled by placentals? On the other hand, there are so many niches that placentals fill that cannot be filled by marsupials.

Did marsupials develop their own fully-aquatic animals, comparable to the whales and dolphins?

how about a little less aquatic, comparable to seals, sea lions, walruses etc.?

now how about semi-aquatic, comparable to otters, capybaras, beavers?

how about flying ones comparable to the placental bats?

how about large-sized species truly adapted to deserts, such as camels, gemsbok, addax?

There is no doubt that species are to fill the niches, however, which niches that marsupials can fill but placentals cannot? Name one.



It's like real life. Burger flippers can be good at their niches, are they not? But a middle-class worker can also be made to do such job and be good at it after some time, but a burger flipper would be unable to do the middle-class job as well as that worker. That's why a burger flipper earns minimum wage.

Have you taken a university level biology course? If you did and were paying attention, you might have noticed that there is no actual race to the top, it is all about survival and in the process weird things happen, how about the duck billed platypus and manatees? It is quite possible that placental mammals are an evolutionary dead end and the next apex predator will be a marsupial. I would like to point out that opossums have opposable thumbs, give them a few million years.

CAPT

[griffon502]

Originally Posted by Capt Kirk

Have you taken a university level biology course? If you did and were paying attention, you might have noticed that there is no actual race to the top, it is all about survival and in the process weird things happen, how about the duck billed platypus and manatees? It is quite possible that placental mammals are an evolutionary dead end and the next apex predator will be a marsupial. I would like to point out that opossums have opposable thumbs, give them a few million years.

CAPT

Trust me, I know way about evolution than you do. You seem to think a race must have a top, that is totally false, evolution does not have a top but this does not mean there is no competition. Race in this sense, simply means competition, and marsupials simply suck at it, I've shown countless evidence in this thread.

Opossums have opposable thumbs, ok, but so does the monkeys, great apes and the lesser apes, giant panda from the bear family, and red pandas. Humans have that too. So what the heck is your point? You think giving them a million years, opposum would suddenly evolve into another highly-intelligent species like human? You are the one without any basic biology knowledge or you simply lack the intelligence to apply it properly.

Manatees are not primitive, they are related to elephants and they *are* placentals. Platypus survived because of lack of competition, import the placental semi-aquatic animals into Australia such as capybara, otters, beavers etc. the platypus would suddenly be full of troubles.

Your fantasy about placental being the dead end and marsupials will be the next apex predator is so laughable. Funny how you claim to be so informed about biology yet loves making such moronic claims. Read post #40 again, it explains why marsupial carnivores are inferior, from locomotion limitation to adaptibility etc.

[The Great Sun Jester]

So...about those Antarctic orangutans.

I suppose there is some extrapolation about the critters that can be made based on what was in Australiachunk and SouthAmericachunk, but what actual fossils have been found there? And where were they found?

And griffon, dude, you seem a bit hostile for a mythological placental. Or are you an ovip? Or a monotreme?

[Capt Kirk]

Originally Posted by Inigo Montoya

So...about those Antarctic orangutans.

And griffon, dude, you seem a bit hostile for a mythological placental. Or are you an ovip? Or a monotreme?

I think a Marsupial ate his baby, seriously now evolution is a bit like mutual funds, past performance is no indicator of future performance. Placental Mammals rule the roost now, that all could change tomorrow ask a dinosaur.

CAPT

[coremelt]

Griffon, Kangaroo's and wallabies of all kinds are thriving in very large populations all through central Australia even thought we have introduced Rabbits, Goats and Pigs now competing with them.

Kangaroo's are better adapted to surviving drought and flood cycles than non-native mammal herbivores, do some reading.

[griffon502]

Originally Posted by coremelt

Griffon, Kangaroo's and wallabies of all kinds are thriving in very large populations all through central Australia even thought we have introduced Rabbits, Goats and Pigs now competing with them.

Kangaroo's are better adapted to surviving drought and flood cycles than non-native mammal herbivores, do some reading.

Do some reading? How about you stop flaunting your ignorance.

Introduce numerous African bovid species, along with the carnivores, and soon the roos will be critically endangered.

The fact is, the roos are thriving because of lack of competition, European rabbit (the only rabbit species in Australia), pigs and goats are ill-adapted to central australia, and they are not direct competitor elsewhere either. European rabbit (Oryctolagus cuniculus) are from Europe where the climate is temperate and of plentiful rainfall, moreover because of their small sizes they do not compete with roos directly, who are able to eat tougher grasses. It's already a wonder how this species which is ill-adapted to semi-arid to arid climate is able to wreck havoc on the eco-system in Australia. Australia has only one pig species, and that is the pig (Sus scrofa domesticus), and it is ill-adpated to semi-arid to arid plains, warthogs are the only species from pig family adapted to plains, but Australia has none. Goats (Capra aegagrus hircus) are originally from rocky terrain and they are browsers, not grazers, and arid to semi-arid climate is not suitable for them either.

And be noted these are only three species total. A tiny representation of their related placentals. Rabbit's relative, jackrabbit for instance, are way more adapted to Australia due to their tolerance of arid climate but they are banned here. Warhogs are banned. Same with the goat's relatives such as argali, ibex etc. and also notice all of these three imported were in their domesticated form, already losing a lot of potential, yet still able to devastate the Australian eco-system.

If Australia is to import wild bovids such as the antelopes (e..g Thompson's gazell, addax, gemsbok, dorca's gazell, impala, spingbok, wildebeest), and bovids from the Bovidae family including the african water buffolo, nilgil, eland, bongo etc. and carnivores such as cheetahs, leopard, and even lions, the marsupials on plains would be totally devastated.

And to eliminate the forest-dwelling marsupial population you just need clouded leopard, margay (both excellment tree-dweller, the tree kangaroos and koalas would be so XXed !!!!!! ), and various placental forest dwellers to ensure a constant food supply for them as the marsupials would be getting decimated.

[coremelt]

Originally Posted by griffon502

Do some reading? How about you stop flaunting your ignorance.

Introduce numerous African bovid species, along with the carnivores, and soon the roos will be critically endangered.

Meh I say release Kangaroos into the Serengeti plains and lets see how they go. Battarou Royale, Marsupials vs placentals.