My point is that this one in particular is pretty new, and was previously completely different (wet and green). I doubt there has even been enough time for much balance to have been achieved. Also some quick googling claims that the amazon rain forest has existed for millions of years (between 10-55 MILLION years), seems pretty well established to me...
Wrong again; you would also notice that it's completely different 8 million years ago.
It's not difficult to distinguish between a population that migrated one hundred years ago and the source population it was drawn from. 8 million years is... longer than that.
No, it's called a continuous ecosystem because it remains very similar. Selective pressure would be very similar, unlike the rare case of certain populations changing significantly when facing a very different situation.
You wouldn't be able to tell the difference between a pine tree from 100,000 years ago to one today, let alone 100. Or a rabbit, snake, bee, fish, or bird.
> You wouldn't be able to tell the difference between a pine tree from 100,000 years ago to one today
Perhaps. Certainly if you put me in front of the two trees I wouldn't be able to tell you which was which. But that's a different question than whether I can tell the difference. If you put me in front of a pine and a fir I couldn't tell you which was which, but it wouldn't be at all difficult to tell the difference.
It might also be relevant that the last time I had any significant contact with any conifer was quite a few years ago.
> it's called a continuous ecosystem because it remains very similar. Selective pressure would be very similar
This is a myth. Specifically, it's the myth of the "living fossil". It's a popular concept, but not a scientific one.
The majority of people can't tell the difference between a coral snake and a king snake. That's not evidence that coral snakes are similar to king snakes.
> unlike the rare case of certain populations changing significantly when facing a very different situation
Not relevant. It also isn't difficult to tell the difference between two populations that were divided by a barrier 100 years ago. Things drift.