Radio observatories on the Moon

His reasoning was that such a small ecosystem can never be stable. You can't have a lawn as a stable, isolated ecosystem. I asked him why he thought that a space colony must necessarily be as simple as a lawn. It was his impression, and anyway, he had created the group and was the moderator. He was a biologist by training, and I assume that he was right in that a closed ecosystem as un-diverse as a lawn cannot be stable. I would say those sealed flasks with the shrimp, algae, and bacteria you can buy now give lie to that assertion. Of course they're not always stable forever (I was just reading Carl Sagan's account of his purchase of one in "Billions and Billions"; his died after a few months). But sometimes they are stable for quite some time. Also, one does not have the opportunity to make the kind of internal adjustments to a sealed desktop curio that one would have inside a space settlement. One of the criticisms leveled at the Biosphere II project was that they tried to reproduce many and varied habitats in their enclosure (basically tried to reproduce the Earth in microcosm), when a simpler, more utilitarian ecology might have functioned better.
Regards, Mike Combs