The Thylacine and convergent evolution?

Question

The Thylacine (Tasmanian Tiger or Tasmanian Wolf) has peaked my interest for quite some time. One of my favorite animals. Allegedly extinct, the Thylacine is a marsupial with a backwards facing pouch (like the Tasmanian Devil), that resembles a wolf, can open its mouth amazingly wide, and has the stripes of a tiger. It is said that the Thylacine is the "perfect example" of convergent evolution. I pose a question as to the origin of this animal if evolution were 100% fact.
Continued...

The skull of the Thylacine is almost identical to that of the American Wolf, yet it is a marsupial, like that of the Tasmanian Devil or the Kangaroo. Because it carried its young in a pouch, then it is pretty impossible to assume that the Thylacine derived from the wolf. They resided on two different continents, Australia and North America. How is it that this type of evolution occurs simply by chance, and create such striking similarities between two completely unrelated animals yet are still different in many ways, living on opposite sides of the world, simply by coincidence?

There are simply completely random mutations, and I find it a bit hard to fathom that in two regions these mutations arose in the exact form, from different mammal classifications. If the two of these animals did not come from a specific common ancestor, than how can it be explained, other than by sheer chance and coincidence? Just because they are similar (and strikingly so as these two animals are) does not mean that they are related in any way, so therefore the same could be said for apes and humans, yes?

Answer 1

It happens all the time with evolution. Its nothing new. there are creatures right now that have paralleled in design and function from different branches of DNA.

In fact, there are all kinds of marsupial fossils all over the world before the continents split up.

Australia is like a living museum of animals that once existed all over the world.

http://www.pbs.org/wgbh/evolution/ Start here.

The Thylacine lived up until the 1920s and replaced by the Dingo.

The Thylacine was hunted down by farmers to extinction.

Answer 2

The short version: the Thylacine evolved among marsupials as a predator. Both the Thylacine and Tasmanian Devil reside/resided in Tasmania, not on the mainland continent that I know of. In isolation, an ecosystem will sometimes develop a predator where none exists if the herbal food supply is threatened.

Other examples: each of the sub equatorial continental regions has a giant, flightless bird. Ostriches in Africa, the Emu in Australia and the Rhea in South America.

Addendum: The same cannot be said for apes and humans, for the DNA does not lie, nor do the fused chromosomes.

Answer 3

It's not that hard to understand. Certain body types are more advantageous than other ones. And the wolf-shaped head is simply a good one for a pack hunter, binocular vision, good all around hearing, large nasal capacity to allow for a good sense of hearing, large biting jaws with meat tearing teeth. And they both derived from early mammals which all have the same vague head pattern.

So basically while the mutations they underwent were random, the process of natural selection is the anti-thesis of random. More efficient body patterns are more likely to reproduce.

And remember it "resembles" a wolf. It's not the same by any means.

Answer 4

Because evolution works by natural selection. And because the Tassie Tiger occupied the same ecological niche as wolves, and had a similar genetic base (mammalian) to develop by that natural selection. Its fascinating, but the species differ hugely in other, more important characters - like you say, one is a marsupial.

And no, the same can't be said of humans and apes. That we are related is based on far more than just the fact that we look most similar in every way, as significant as that is. For example, there is forensic genetic evidence, like retroviruses occurring in the exact same places in our respective genomes, etc.

But at least its a reasonably intelligent question... and includes my favourite animal.

Answer 5

Convergent evolution explains why two unrelated organisms look alike. Evolution responds to environmental stimuli, so it is not unreasonable that the "end result" of evolution within two lineages in similar environments will resemble each other. After all, traits selected for in one species will most likely also be selected for in the other.

A classic example is sharks and dolphins. Two totally unrelated species, but both look very much alike; they have evolved to be top predators in the same environment. Yet both are clearly different animals.

Answer 6

The thing about apes and humans is there is direct correlative genetic evidence that links us to them in the recent past. The same cannot be said for wolves and thylacines. Furthermore, similarity in morphology does not necessarily imply recent common ancestry; take the Zebra and the Horse, for example.

Also, try not to use the phrase "100% fact" when referring to scientific theories.

Answer 7

Your problem is you seem to thing what causes species to change and evolve is "random chance". Having a long snout was benefitial to the ancient proto-wolf for the same reason it was benefitial to the proto-thylacine. They were both predators that feed on the same sorts of things. Those who had long snouts survived and out competed those who did not.

Answer 8

At this time, when the race of man and humanity, struggles to maintain its humanity if only to be classed as humans, the lot of an animal falling into extinction presumably because the savagery of its creed has, by natures process of elimination cancelled and destroyed itself is of little consequence.... As it should be....Mother Nature knows best.

Answer 9

Your reasoning was going fine until you mentioned by chance. Evolution is not a chance event. It is natural selection.