I am writing to try to unblock myself. Suddenly I lost a bit of confidence in writing and I have to start writing my dissertation. I am planning to start it tomorrow. I will write about ecosystems now, although my dissertation is about evolution of moths.

I was reading - but I did not finish it - about the scientific and philosophical debate of the concept of ecosystem. I think it is a very important term for the whole biology and for the entire population living on this planet. We do have to conserve the ecosystems. But it is true that ecosystem is somehow loosely defined. When does an ecosystem start and another finish? Is it possible an ecosystem to have a lot of sub-ecosystems, in which the former ecosystem is much bigger and complex? (I would guess it is called Earth). But, anyway, there are boundaries and barriers, beyond elementary differences between systems, in this case ecological systems. I understand that a system has some kind of mechanism, in which its parts are integrated to produce a final outcome. In ecology, there are the foodwebs and trophic relationships among the organisms in a given location (Wolf eats deer eats grass… - in the Yellowstone National Park [I am Brazilian and give an American example, probably because it is much more studied). Then, I think, there is an ecosystem when these organisms are tied enough to produce some kind of stability within the system. Here, there is another problem, what is stability? It is kind of trick. But it might be when, in a given location and system, the amount of energy that passes through the trophic relationships (through all the relationships between the organisms) does not fluctuate too much. Then, there is the ecosystem functioning: how do we ensure that the relationships are tied enough to maintain the system? How to avoid collapse? In the video bellow they say it is diversity - biodiversity. It is probably related to some principle of redundancy and resilience. There are many organisms doing many things, there are many links making the system strong. Once one link is missed, if there are many others, the system may be resilience and not suffer too much.

You may agree that ecosystem is still not very clear. But I think it is a useful term and we need to think in entire systems to conserve nature.

I have an evolutionary background, that’s what I have read most, and evolution is change, not stability. We seek for ecological stability and maintenance of ecosystems functioning – and I totally agree. But, arguably, things change through time. (This is only a theoretical exercise). If evolution might produce diversity (but might not), and change produces evolution, how stability may produce biodiversity? Might change produce diversity and stability only maintain it? Would the higher rates of diversification of species be when the environment is changing? Would stabilized ecosystems slow down evolutionary change? I find it a bit paradoxical. Of course that too much change may be devastating, provoking mass extinction. But I also think that an ecosystem is never stabilized, even in its healthy and "stable" form. There are variations among organisms that emerge on each generation, making the system very dynamic. There are fluctuations of many kinds. We seek for ecosystem functioning, which is dynamic and may change.

I think ecology is an exercise of a different kind of logic. We seek for a stability that is never there, for a functioning that is essentially different on each new generation, but we still have to study and conserve it bravely because its collapse may be very real and devastating.