I recently finished Rick Bookstaber's A Demon of our Own Design. It's a very nice book about markets and liquidity—although it could have used a bit more editing. After reading it, I began to wonder why we don't see markets and liquidity in nature, i.e., biology. Certainly some natural (decompositional) processes break down larger units of energy (and other resources) to produce smaller units. And much of biology consists of aggregating smaller units of energy and other resources to serve larger units (like us). But there doesn't seem to be anything that corresponds to a naturally occurring (biological) market for energy or other resources.
Even more to the point, I can't think of any naturally occurring free-standing biological entities that make their living by providing liquidity to other biological entities. Perhaps fat cells do that within biological organisms. (Although is that really a liquidity function or just a savings function since fat cells are "owned" by the organism they serve?)
One problem is the lack of a medium of exchange, i.e., money. But it would seem that some form of unit of energy should work for that purpose. Yet none seems to have evolved.
Those of us who work in the field of complex systems find market mechanisms to be important in much of what we do. We also find naturally occurring mechanisms to be important. Yet markets and liquidity do not seem to be naturally occurring at the biological level, i.e., outside human interactions. That's strange because nature is usually so good at exploiting situations that are potentially profitable. I'm not sure what to make of that—other, perhaps than to say that like conceptualizing itself this may be one of the innovations that human beings have added to biological processes.
Perhaps one reason is that nature tends not to operate on a very capitalistic model. That is, there aren't good examples of savings being accumulated and then invested in new ventures. The only counter-example that I know of is giving birth. Every birth is a capital investment. Of course that's very widespread, but it's also very constrained and stereotyped. The investment that is made in giving birth generally can't be converted to something that might have been invested in some other way.
So if there is no free capital, then perhaps there is no need for liquidity.