Non-Darwinian science: Gaian challenge to Darwinism?

The Gaia hypothesis treats the whole earth as an organism, which I think is a very reasonable view, as long as it does not lead to obese, middle-aged Englishmen prancing around naked in the woods. (No view that leads to that outcome is reasonable, no matter how well-founded otherwise.) But seriously, here's an interesting item from Astrobiology Magazine, "Can a biosphere be selfish?", in which the reviewer Charles H. Lineweaver notes that Gaia advocate Lovelock and others raise some key questions re Darwinian natural selection:

On the surface, natural selection and Darwinian evolution are simple ideas, but a fundamental debate has been percolating for years: What is the unit of selection? A gene? A chromosome? An individual? A group of individuals of the same species? An ecosystem? Do ecosystems compete with each other? If so, when one ecosystem out-competes the others and comes to dominate the biosphere, can we say that the characteristics that led to its success are the products of evolution? Maybe regulatory mechanisms, which are now global and seem to have no competitors, were once sub-global with competitors.

Forget the debates with creationists and intelligent designers; the scientific debate about the unit of selection is one of the most important challenges that Darwinism has ever had to face. The chapters of this book pose that challenge by asking, again and again, how could the biosphere evolve to regulate the Earth?

Well, that is an important question, certainly. If natural selection is alleged to create all the life we see around us, it certainly doesn't help that we don't know what the unit of selection is.
Lineweaver also cautions, sort of, regarding the Gaia hypothesis:

When we begin to wonder whether our Galaxy is a life form called Galactea, do we become so open-minded that our brains fall out? Maybe this will be the subject of the next Gaian conference. Let a thousand flowers bloom, right in the middle of a cow paddy.

Or not. Let's get back to some more basic this-planetly questions.