Humans are the world’s most dominant species.
I think this is something that most people would agree with, but probably for different reasons. While other organisms may be more numerous (like the Pelagibacter ubique bacteria, thought to number ~10^28 ), or contributing more total mass (also probably the Pelagibacter ubique bacteria, which is estimated to have a collective mass more than the sum of all fish in the world's oceans ), humans are at the top of the food chain.
It’s not just that we’re smarter than everything else though--it’s that we can do something with the knowledge we have. I don’t mean that in a righteous way. I mean that as humans, we can physically change our environment based on what we learn from the environment. And we can collectively do that to a greater extent than any other species.
The list of physical systems that have some control over their own persistence is pretty short. In fact, it’s a list with one word--and that word is life. Everything else is fully at the whim of its environment. Life persists outside of equilibrium with its environment. If you change an environment slowly enough, life will find a way to ensure its persistence. However, non-living systems will always be moving towards equilibrium.
(E.g. If you changed a frozen tundra to a hot desert slowly enough, polar bears would be able to adapt to their environment in order to persist. Now picture some salt crystals. No matter how slowly you increased the amount of water around the crystals, they would eventually dissolve. Crystals have no control over their own persistence.)
Now, let’s think about how different living systems have different levels of control over their own persistence. All life that we know of is based on the genetic code, and has the ability to genetically evolve over evolutionary time in order to adapt to a changing environment. Alternatively, life can ensure its persistence by moving to a new environment that more closely matches the environment to which it is adapted. Yet a third way for life to persist over time is to create micro-environments. These micro-environments allow organisms to persist in an environment it’s evolutionarily adapted to, within the context larger inhospitable environment.
If an organism’s environment changes quickly (within the lifespan of a single organism), it cannot rely on adapting through genetic change. Instead, the organism must persist through one of the latter two methods described in the paragraph above--by moving to a new environment, or creating it’s own microenvironment.
(E.g. Imagine another polar bear, living on the edge of the arctic circle. The arctic ice sheets are melting, and they’re melting fast enough that the polar bear can’t adapt to it’s current environment through evolution. So the polar bear moves further north in order to persist. But this is only helpful for so long, since the warming is a global phenomenon. If it continues, the polar bears will go extinct because there will be no cold places left to go, and no time to adapt to the new warmer environment.)
Humans do not have this problem. If the world keeps warming, we’ll just create micro-environments (e.g. buildings) that allow us to persist, using technology. Humans, I would argue, are the most dominant species because we can persist through environmental changes that happen on timescales shorter than the lifetime of an individual human, even when the environmental changes are drastic. We can do this because of the micro-environments we can create; our deep understanding of the environment; and the control we have over ourselves and the environment.