Talk:Monster Hunter Evolution - My Theories/@comment-5913830-20120909195248/@comment-4212769-20121117195537

Not whole species evolve into something different only some individuals change through mutation and form a new species when they bring those mutated genes into the new generation leading to a new species if that happens repeatedly. So the species itself is still there but a new one evolved out of it.

And that's exactly why Tigrex could be the ancestor. Tigrex live in more than one environment so it cannot be easily outcompeted as it can just go somewhere else to live. But mutations mostly happen completely random. A Tigrex having a mutation maybe stays longer in an area than others because it got a mutation that helps it to live there better so that it can stay longer there. Exactly that is the time when it needs to adapt because this mutation could do the opposite to other environments, means it has more problems to live there. So when this Tigrex gives its genes to the next generation more and more of them have these genes and live on there and adapt to this environment. And so piece by piece a new species is formed that can form more monsters.

This can happen in all habitats Tigrex lives in so that all have their Tigrex descendants. But of course Tigrex evolves, too, but as nomad it cannot adapt to any environment so there are only minor differences in evolution so that those still nomadic stay pretty much the same.

And the sentence "If it ain't broke, don't fix it!" doesn't fit at all, because it isn't "fixing" anything but "improving" something and every animal on our planet and on their planet still can adapt even more to their environment. Evolution never stands still.