Marsupial evolution

see my later postEdited by randman, : No reason given.

You guys pick subspecies and species more similar within placentals to compare with a marsupial. Let's look at a wider range to test your claims, shall we.How many teeth are in this critter? http://www.sensesofwildness.com/africa/2_4/04_42.HTMHow many in some marsupials?The fact is you are going to have to take a comprehensive look at all of the features of marsupial and placental pairs to substantiate the claim that all placentals are more similar than their marsupial pair. For example, do you really believe a marsupial wolf is less similar to a placental wolf than a placental wolf is to a human being?Humans have 2 legs. Both placental and marsupials have 4. Marsupial and placental wolves skulls are much more similar than they are to a human's skull. Their anatomy and behaviour are more similar. The only area they are primarily less similar is their reproductive system.Your claim is a human being is more similar to a wolf than a wolf is to a marsupial wolf. I doubt that and list a few items above. Please show something more than small differences in molars or items such as that.Do you really think a human skull is more similar, for example, to a red fox than to a red foxes skull is to a marsupial wolf?

No I am recommending that you go and talk to the director, see if youi can get behind the scenes to see actual skeletons and fossils -- this is where they are kept, if you don't know. The Smithsonian and the ROM in Toronto are other museums that have evidence in storage. Similar but different: no placental animal has a pouch, thylacines have a pouch. This is a substantial difference from the wolf.The similarities are either due to convergent evolution or heredity, and the way you determine that is by investigating the ancestral lineages. You don't start and stop with the evidence of todays species.Homologies or analogies -- that is the question. No, I am suggesting that when you compare homologies and the actual lineage of today's species from ancestral species that you will find that the apparent similarity of wolf and thylacine diverge before they come together in an ancient common ancestor. Conversly the wolf and the bear will merge. Unfortunately for you, reality is completely unimpressed by your opinion, nor does it feel constrained in any way by your belief of what is true. Yes, every bear listed having the same number and pattern of teeth as the wolf, and no carnivore on the page having a pattern similar to the thylacine, fails to substantiate the point that wolves and bears are more similar than wolves and thylacines ... if you're a creationist that doesn't look at the evidence.Enjoy.Edited by RAZD, : .

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The thylacine again for reference:

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Tasmanian Wolf
Order: Dasyuromorphia
Family: Thylacinidae
Thylacinus cynocephalus
Skull Length: 22cm / 8.7"
Origin: Tasmania
Carnivore
Incisor 4 top / 3 bottom
Canine 1 top /1 bottom
Premolar 3 top /3 bottom
Molar 4 top / 4 bottom
x 2 sides = 46

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I gave you a source to see how many teeth and which kinds:
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Bat-eared Fox
Order: Carnivora
Family: Canidae
Otocyon megalotis
Average Skull Length: 11.4cm/4.5in
Origin: Africa
Carnivore
Incisor 3 top / 3 bottom
Canine 1 top /1 bottom
Premolar 4 top /4 bottom
Molar 3-4 top / 3-5 bottom
x 2 sides = 44-50

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Similar molar count, still different incisor and premolar count. What you have is a carnivora species that evolved additional molars, but not additional premolars or additional incisors. No this animal does NOT match marsupial patterns. The fact is that this has been done and it has been done for some time. We don't need to reevaluate everything in science just to please your lack of understanding and ignorance based on your unwillingness to investigate the issue.

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Note that the Bat-Eared Fox is on the list of carnivora that I supplied before: There are still no animals on that list that match the teeth pattern for the thylacine.Access denied

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American Opossum
Order: Didelphimorphia
Family: Caluromyidae
Didelphis virginiana
Average Skull Length: 11cm / 4.3"
Origin: North America
Omnivore
Incisor 5 top / 4 bottom
Canine 1 top /1 bottom
Premolar 3 top /3 bottom
Molar 4 top / 4 bottom
x 2 sides = 50

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Woolly Opossum
Order: Didelphimorphia
Family: Caluromyidae
Caluromys sp.
Skull Length 5.5cm / 2.17"
Origin: Central and South America
Omnivore
Incisor 5 top / 4 bottom
Canine 1 top /1 bottom
Premolar 3 top /3 bottom
Molar 4 top / 4 bottom
x 2 sides = 50

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Based on the teeth, the thylacine is more similar to these opossums than it is to wolf and bear. Funny that they also have pouches ....You can also look at the list for marsupials, similar to the one for carnivora
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and you can see the same kind of variation within marsupials as within carnivora.The classification of animals into the various taxons is not based on any one characteristic, but the whole animal. Arachnophilia's post showed two other features on the skulls where marsupials differ from mammals, there are others, and we haven't even started to talk about genetics.Taxonomists have been doing this at least 270 years since Linnaeus formalized a system of nomenclature ...
Carl Linnaeus - Wikipedia

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The first edition of Systema Naturae was printed in the Netherlands in 1735. It was an eleven page work. By the time it reached its 10th edition (1758), it classified 4,400 species of animals and 7,700 species of plants.

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... and the field of taxonomy was already old then.Do you really think you know something that everybody that has actually studied the subject somehow missed?Do you really think biologists and naturalists are ALL that dumb?Enjoy.Edited by RAZD, : fixed ubb
added material below lineEdited by RAZD, : .

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You are still not taking a comprehensive look. You are looking at only a few traits, and that's not sufficient. You and many evos prefer to trumpet dentition. However, that's cherry-picking the evidence. You are not looking at all the evidence, nor does it even make that much sense.Why would convergent evolution produce so many similar traits and yet not similar dentition?Doesn't make sense. If something like the mouse body-design, traits, etc,...or wolves/dogs can be so similarly reproduced because, according to evos, there is such a strong environmental factor, then shouldn't this also produce similar dentition?When you peel away the simplistic analysis and really look at this, the adaptionist position really falls apart. If mutations are random, there is no reason for the same niches to be reproduced and the same patterns. It's not like there is only one set of niches that can be produced by the environment because the environment in a great way includes the animals and plants that are there. The idea the same animal forms should be produced is ludicrous on the face of it.Moreover, there is no evidence that differences and similarities in dention should be the result of common ancestry. In fact, I suspect it is more likely that the differences relate to the different reproductive processes. Keep in mind organisms are not simply a bunch of parts put together but work within themselves individually in a dynamic process.

What I'm telling you Randman is that taxonomists have looked, and continue to look, at every little detail to see how much each individual specimen differs from the others. They also know which elements are more useful in classifying animals than others, and teeth are one of the ones that turn out to be useful for this.You don't know this for the simple reason that you don't know this. Because convergent evolution DOESN'T HAVE TO. Nor do they need to turn marsupials into mammals. They don't need to make the foot usage \ articulation similar either, or the fur markings, or any of the other differences already mentioned. All that is needed is to fill the carnivorous approximately dog-size niche. Or in N.America, fill the carnivorous approximately thylacine size niche. AND they only need to be better at it than any other LOCAL resident, they don't compete (normally) with each other due to being on different CONTINENTS. Mutations don't produce niches. The environment produces niches, like grasslands in asia, africa, n.america, s.america and australia. Surprisingly there are grass-land dwelling animals in each one, SOME of which are similar to others and SOME of which are different. How many different kinds of hoofed animals do we need? Which is why it is evidence of evolution and not design eh? It would be pretty silly for a designer to do that.Enjoy.Edited by RAZD, : moreEdited by RAZD, : .

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So you admit the few traits you have mentioned are cherry-picking and not comprehensive. What you don't say is that the taxonomists and classifications being done by evos assume universal common descent and so use an assumption as a large basis for what they are doing.Sorry, but that doesn't cut it. It's similar to just saying that evos believe in evolution and so it must be true. Wrong. Mutations are part of the environment because the organisms which contain mutations are part of the environment. Niches are not simply the result of the inorganic environment but the bio-environment, which is why things like invasive species can have such an impact. Selection pressures are not simply produced via the inorganic environment. Take away a predator, for example, and keep the land the same, and you will see changes in the animals there due to their bio-environment changing. Introduce a disease as a result of it's virus or bacteria mutating and becoming more lethal and keep the land the same, and you likewise see changes.Frankly, I am surprised you don't already understand this.Edited by randman, : No reason given.

This is perfectly true but it is a stretch to then posit that random mutation means effectively random niches. Niches need not be exactly identical to produce similar pressures which may lead to convergent evolution.TTFN,WK

I didn't say perfectly random niches. But there is no reason for near exact duplication of forms in placental and marsupial pairs. Furthermore, they don't even have the same environment. Once again, this is just another untested hypothesis which evos accept as true as if it needs no verification at all. It MUST BE true according to NeoDarwinism and so evos insist it is, but they have done no real studies and means of verifying it.Edited by randman, : No reason given.

Well neither did I. If you aren't saying that random mutations are introducing a significant enough random factor to radically alter the environment in a random manner then what was your argument? So far you don't seem to have made a compelling case for the 'near exact' level of duplication. I agree, to the extent that they don't have identical environments, but in some cases function dictates form to some extent, i.e. the shovel shaped paws of marsupial and mammalian moles. Do you just assume this? There are lab based studies on convergence in viruses (as you yourself referenced in another thread), bacteriophages (Bull et al., 1997), and Drosophila (Matos et al., 2002). The Bull et al. paper is actually probably better than your SIV paper for showing genetic convergence since it details their subsequent failure to reconstruct what they know to be the true phylogeny from the complete genome sequences of the virus.TTFN,WK

Well, I am saying ASSUMING for sake of argument common descent via random mutations, etc,....that the make-up of the available animals and plants which presumably is indeed produced via this random process (according to evos) is a VERY significant aspect of the environment. That is just a fact.Neodarwinian evos are adaptionists claiming the environment and even very different environments are such a powerful influence as to produce the marsupial and placental pairs. This hypothesis is not supported by any actual studies and empirical data and is highly illogical. For one, the nonbiological environment is markedly different between places, and another the environment also includes the biota within it. Since you agree with me on genetic convergence or at least to a degree, why didn't you just say that up-front (as I already suggested you had agreed there were studies indicating that before)?However, genetic convergence is different than the adaptionism aka as NeoDarwinism which insists that the environment is the crucial commonality creating marsupual and placental pairs. In reality, the adaptionist position is untested here. The evidence supports the front loading or interior mechanism position (men like De Grasse) so often derided by Darwinists.Now, just for the record, I am not saying I agree with de Grasse, nor the IDers of today that advocate front loading, but there position is definitely more in line with the facts than NDists aka as evos.

Randman, I haven't seen anybody claim that the environment is responsible for the convergence between thylacine and wolf. In fact, I'm quite sure they said it was their ecological niche. The thylacine family (yes, they have their own separate family) evolved alongside large herbivores that were probably not ecologically very different from ungulates. So, thylacines likely evolved to hunt things that are very similar to the things wolves evolved to hunt. Doesn't it make sense that these two animals would evolve similarities based on similar life history traits?

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Darwin loves you.

Really? So why would their ecological niche be the same? Keep in mind there is little reason to believe a random process would duplicate itself unless there is some other factor. The other factor evos usually give is the environment. Keep in mind the ecological niche is produced, presumably, by the available biota, and the available biota certainly differs in different parts of the world, and increases presumably according to evos by random mutations conferring selective advantage and creating evolution.There is absolutely therefore no reason ND processes should create placental and marsupial pairs. Carnivorous dinosaurs and other carnivores eat large herbivores too. It's not like dogs and thycines are the only predators that could evolve in this niche. There is no reason to expect a duplication in a random process. Not really. All sorts of creatures could evolve and do the same thing. Don't large cats eat the same prey, for example?How about marsupial and placental mice? Marsupial Rats and Mice - Species, Australia, Spp, and Predators - JRank Articles Why should marsupial mice be so similar to placental mice when they are ecologically "simmilar" to weasels, for example, and play a role more similar to shrews, similar to mice but not exactly the same? Marsupial Rats and Mice - Species, Australia, Spp, and Marsupials - JRank Articles

Has it yet dawned on you that you are the only one here using the word “same?” I have often had people tell me that I look a lot like someone they know. Once, a girl kept insisting that I was this person named “Jacob” (that’s not my name), and thought I was only teasing her by pretending that I was someone else. I have also seen many people who look like other people that I know, despite having no known relation to one another. You wouldn’t expect random birthing events to produce two individuals that superficially resemble one another, yet this phenomenon can be readily observed. What’s your problem with that? So now, instead of two look-alike mammalian carnivores, you think there should be three? Just because two animals came up with similar solutions to similar problems, doesn’t mean another group can’t come up with something different. Why shouldn’t they? You seem to think evolution is an intelligent designer that makes perfect matches between morphology and ecology. If two things happen to look like one another, and neither is at a disadvantage for this, how could natural selection undo it? ToE is not entirely adaptationist, you know.The lack of perfection is beautiful evidence for evolution.Edited by Bluejay, : Added final line.

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Darwin loves you.

You still offer no reason for placental and marsupial pairs. The reason why there should not be pairs is that evolution is supposedly a random process in terms of mutations. The reason evos give is the environment but the environment is different and the ecological niches are different.