It's fascinating to me that the complexity of life always goes up. Outside extinction events, complex life generally seems to become more favourable over time. It's interesting that (to my knowledge) we don't see an ecosystem lose complexity in its entirety unless it's dying. Simple organisms make a bedrock for complex organisms, and while the complex organisms have more specific needs, they are better at exploring,…
Another cool perspective is that simple organisms evolved to coordinate with each other to build complex organisms that could protect the simple organisms in hostile environments they might not / would take longer to explore. Think about all the gut bacteria that survives in humanity during reproduction and viruses and bacteria that invade and hitch rides. You can view humans as the life form or you can view the bact…
But the bacteria aren't the whole story - we also have our own cells, all doing their thing and all participating (even if bacteria in us are -also- participating). We're just groups of trillions of cells all working together to keep themselves alive and reproducing.
And then we go work together with other blobs of trillions of cells, just to further that goal: survival of the cells.
These groups of cells that started working together many, many billions of generations ago, are now looking at space exploration, colonising other planets, and wondering if there are other big groups of cells on other planets.
There's no way they'd have gotten there if they'd kept living alone as single-celled organisms.
That's fun to think about.