Meandering Amazon Leads to Bird Diversity 

A correspondent has sent me a couple of links from Quanta Magazine which, while not very geological, are very interesting. THIS IS THE FIRST LINK and THIS,THE SECOND. The first link is introduced in this post, the second on a NEIGHBOURING POST. 

Quanta Magazine produces many interesting articles and I have subscribed to their NEWSLETTER

----------------------------------------------

The author of THIS ARTICLE refers to THIS ACADEMIC PAPER. The thesis is that birds which are weak fliers will find the wide rivers of the Amazon Basin a formidable barrier. So it is very probable that a change in the rivers course will lead to bird populations becoming isolated. And isolation leads to genetic divergence.

But meandering rivers being what they are, isolated areas can come back together. The diverged birds of a single species may have changed so much that they cannot interbreed - new species have been formed. But mostly they can interbreed and the species diversity has been increased.

In the academic paper this is examined in exhaustive detail- detail which I find incomprehensible but which looks convincing. 

This may be one more reason for the Amazon having such great species diversity.

A satellite image of the Amazon lowlands shows the immense complexity of the constantly changing network of rivers carving their way through the forest landscape.

NASA Earth Observatory/Jesse Allen