I've read there many be more biomass in the earth's crust than above it. This data on biomass is spurious at best. We're in the middle of a process, call it an evolutionary bloom. No process can be expected to last forever. A crystal stops growing, suns burn out, etc. However, some processes cycle (a flower blooms then disperses pollen and seeds).

Most eastern religions embrace the cycle, while western religions tend to have beginnings and endings. I don't think at this time we have a good idea whether we are part of a cycle or a one time thing. I do think it is fairly certain that without the intervention of man's technology, most of the biomass on earth will suffer a premature death by asteroid or cometary strike. So, that pretty much puts to rest that man is the best example of af the Medea hypothesis.

Both the Gaia and Medea hypothesis attempt to put some label of "good" and "bad" on the evolutionary process. I think this is absurd. The process just is. Human beings are the result of a emergent game theoretic evolutionary process. Meanwhile, rather than putting some sort of mystical expectations on the evolutionary process, I think we will just have to wait to see where it leads. The fermi paradox seems to put some constraints on that.