Not Just Drops of Goo
The smallest idividual droplets of life are fundamentally different from one another, as opposed to physics or chemistry where the fundamental parts are interchangable. There are at least 100 million distinct types of droplets (excluding viruses, proteins, and undiscovered types), each with its own inherent and combinatorial talents. These special abilities are written out in the droplets' DNA, so that every tiny snippet in my body is fundamental to me and contains the possibility of me.
People and animals and plants (and indeed all life) were not put here randomly-- we each have a reason. Sometimes that reason is just because here is near where our parents happened to live. Everywhere in the world children live near their parents. But if you go live on an island you would become different. The 'you' that you are can't go live on an island without becoming a different 'you'. The 'you' that you are is based on where you are. And so all life forms are different in different places. Yet Darwin teaches that they are the same stuff, from the same parents. We are all brothers and sisters, made of the same protoplasmic ooze.
This, then, is the tension in biology: we are all fundamentally the same goo but we are all fundamentally different goo. "There are no differences but differing degrees of difference and non-difference." CF. "The Influence of Darwinism of Philosophy", 1909 John Dewey.
"All species are absent from almost everywhere"
But: not everything important is alive - rocks, sunlight, clouds, motorcycles. All of these things push and shove on each other and on life. So to study life we have to study all of these things. Life itself is constantly bouncing against itself and, in fact, this is what makes life alive. What does this constant bouncing need to keep going? It is many things in many places; different things in different places. It is often a balancing act between hot and cold, between light and dark...
Everything in nature is good at something; balancing, breathing, sweating, slurping. But the sad wisdom Darwin teaches is that we only know we were good at something in the past - who knows if we will fit in the present or find a place in the future? There is evidence all around us of stranded animals and plants and people who stayed while the world changed around them. The past is no garuntee of the future.
The fundamental questions of Ecology: Why does this thing live here (why am I here) and Why do different things live in different places (Why am I different)?