I have this vague intuition that some water-living organisms have fuzzier self-environment boundaries than most land organisms. It sorta makes sense. Living in water, you might at least get close to matching your nutritional, hydrational, thermal, and dispersion needs via low-effort diffusion. In contrast, on land you almost certainly need to create strongly-defined boundaries between yourself and “air” or “rock”, since environments can reach dangerous extremes.
Fungi feel like a bit of an exception, though, with their extracellular digestion habits.
I have this vague intuition that some water-living organisms have fuzzier self-environment boundaries than most land organisms. It sorta makes sense. Living in water, you might at least get close to matching your nutritional, hydrational, thermal, and dispersion needs via low-effort diffusion. In contrast, on land you almost certainly need to create strongly-defined boundaries between yourself and “air” or “rock”, since environments can reach dangerous extremes.
Fungi feel like a bit of an exception, though, with their extracellular digestion habits.