We start with:
First, permission is gained from students to introduce a dissection of a shrimp.

On the day or the one before, I start with a word splash on the board. These will be about anatomy, dissections, body parts e.g. abdomen, head, appendages (legs, antennae), eye, etc
What might have these things? Is it living or non-living?
What other information do you need before you could tell exactly what it is?

I guide this to:
How do we scientifically classify living organisms?
How did we come to know about anatomy of living things?
What were the methods of investigation?