(I assume you’re a fan of process philosophy? If not, check it out!)
I’m interested in understanding what you mean.
However many years ago there was a ‘beginning’ of the organism DanMcD.
However many years hence there will be an ‘ending’ to organism DanMcD.
In-between the organism persists and evolves in a unique particular way.
Do you agree? If so why wouldn’t you call the organism an individual?