Randman, I haven't seen anybody claim that the environment is responsible for the convergence between thylacine and wolf.
Really?
In fact, I'm quite sure they said it was their ecological niche.
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.
The thylacine family (yes, they have their own separate family) evolved alongside large herbivores that were probably not ecologically very different from ungulates.
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.
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?
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?
In a sense, marsupial mice fill the ecological roles played by the smallest placental predators on other continents, for example, shrews, while the marsupial rats are ecologically similar to larger small predators, such as weasels.
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