A piece of material is not conscious because it doesn't need to. You see, bacterias are self replicators, humans too. And self replication is resource intensive, while resources are limited. So life becomes a competition. That is why agents need to become more attuned to their state and possible actions and outcomes.
Is that good enough to be called consciousness? Taking sensory inputs, representing your state, taking actions, observing effect, learning from it. Your goal - to exist, to make copies of yourself. If you're not aware of essential information, or don't understand your situation, you die. If you live, it's because you are aware.
It's not interacting with anything else to make those decisions, it's completely autonomous.
> observing effect, learning from it
If something is meaningfully doing that, then we're getting to consciousness. But I'll note that I don't count natural selection as "learning" here.
And observing the results of decisions and learning is not mandatory to survive and reproduce.
It is about having subjective experience aka "qualia". It is about "it being like something to be you", contrasted with, e.g. being a rock (which most people agree, it is not like anything to be).