xxSilverPhinxx

I don't know, if the tiger is anything like a slightly weaker version of a lion, who can kill a lioness with one swip of their paw, then the Great Danes might run into some problems. However, I know that Brazilian mastiffs, which are roughly the size of a bull mastiff were used to hunt jaguars (and catch run away slaves, but that's besides the point).

One on one I think the tiger would win, though.

The classification or organisms is taxonomy, and as for ecology, the wiki link explains it well. It's basically the study of ecosystems.

If chickens don't have arms and hands, then where do chicken fingers come from?

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As for the question:

I don't think it would be an example of reverse evolution, or "de evolution", but a new molding of a limb they already have if there were selective pressures that favour the remolding.

Dolphins have the fish, reptilian and higher mammalian (like us) parts in their brains.

There's a fascinating (and at times quite acrimonious) debate on this and related issues between Stephen J Gould of Harvard University, and Simon Conway Morris of Cambridge University.

 

Gould argues that we arose completely by chance and that "if the tape of life were replayed" intelligence would not necessarily have arisen, because evolution is so random and easily influenced by minute events (i.e. the butterfly effect).

 

Conway Morris says that Gould is completely wrong and points to convergent evolution. This is the independent evolution of the same traits in completely separate lineages (for example, flight in insects, bats, pterosaurs and birds). He uses this (and quite a few other examples) to suggest that intelligence is a natural endpoint of evolution.

 

This debate is still ongoing and nobody really knows the answer. As with all endmember views, the answer probably lies somewhere in the middle.

 

Would life have evolved on another planet? That depends on how similar you think alien life has to be to that on planet Earth. I've been reading a little about the subject recently and it basically comes down to how you define life.

I think the brains of marine mammals such as whales and dolphins are interesting because though they're separated from our lineage by a few million years, they've evolved a similar brain cortex.

Evaporating water takes more heat away from the surface of our skin than a fan removing heated air from the proximity of a dog's body, but the principal is the same. It's just not as effective for them but it happens.