I wouldn't think it would extend beyond the boundaries of a single biological entity. As far as we know, cells need to be in very close communication with each other in order to produce what we call consciousness. They do this by releasing chemical signals into their surrounding environment that then modify surface structures of other cells which then triggers some process within those other cells. It's not clear that consciousness could be shared via other means. I'm open to being proven wrong by ventures like Neuralink though.

Right now, neurons in your head are firing and generating thoughts and concepts in response to light hitting your eyes in patterns that were created to represent thoughts in my head - there is a chain of direct physical phenomena that stretch from my brain to your brain that are affecting thoughts in your head right now. In person, it's even more direct - neuronal firing patterns in my brain cause jostling air molecules which incite neuronal firing patterns in your head. In a very real and direct way, my neuronal firing patterns influence your neuronal firing patterns.

What's amazing is that this extends out through time and distance - my neuronal firing patterns are shaped and affected by the neuronal firing patterns of beings long dead through both the same direct mechanisms described above and more indirect mechanisms mediated through other beings over time - in fact, by the time you've read this far, I'll have indelibly impacted your neuronal firing patterns. You'll never think again in a way that's not influenced by my thinking.

I would, here are two arguments...

You and I are sharing a thought. This thought I am writing at you, implanting in your brain via words you understand... is fundamentally the same as the messages between cells in your body... a message is a message is a message, regardless of the methodology of the message.

Just being intelligent, and just being able to pass messages back and forth is all that's needed for a consciousness to be made up from the parts - it may be hampered by latency. But the default is that this process scales indefinitely.

If that's not convincing - here's an example of how this plays out in our day to day lives at a smaller scale than the whole species... you're work... you work in a group... that group has goals and desires the members of that group reach a consensus towards... precisely like the cells in your brain, taking various inputs from stimuli - reach a consensus to form your conscious experience...

even when we are separated by physical distance - we create connections to each other to mitigate that distance. planetary distances are small enough that connections might be fast enough...

I would default to {maybe: (bet on yes) }.

Yes, you can certainly make this argument. As you start going up the scale, theories about this become more and more indistinguishable from religion and/or magic.

What is God if not some consciousness so large you cannot perceive it?