The first sacrifice

I.
Why aren’t fish dissolving into separate cells after death?

Lets do decision theory: for each single cell, the choice matrix is:
Stay attached: 0% chance of survival, guaranteed death by starvation or predation
Roam away: some minuscule chance of living as a lineage of unicellular plankton

“They”

Ii.

Your house is full of trash.

That’s an easy problem to solve: you have a mop and a bucket. There’s a second bigger problem though: you’re also lazy.

Luckily youre a replicator. You can spawn a clone of yourself and tell it to do the job you dont want to do.

Naturally, your clone also gets your laziness. And your replication