When the special visitor walked into Matt Spearing’s AP Environmental Sciences classroom on Friday, she had to pause for a moment. The room, with its lab tables, late afternoon light filtering through the windows, and fish swimming in a small tank, felt very familiar.

This was the same Scott Hall room was where Melissa Dore ’86—who now works at the Halmos College of Natural Sciences and Oceanography in Florida—first began her journey into biology.

“Thirty-four years ago, this is where I sat,” said Ms. Dore, the director of academic support and administration at Nova Southeastern University’s Halmos College. “I did my first shark dissection in that classroom. And a lamprey eel.”

On Friday, Ms. Dore returned to Scott to talk to AP Environmental Sciences class about sea turtles. She then headed over to Elizabeth Kay’s biology class for a marine animal version of “what am I?”

Along the way, Ms. Dore shared quick facts about turtle eggs (oil will kill them), sting rays (can’t see what they eat), the gulf stream (it’s fast), and sharks (you have a better chance of being squished by a soda machine than eaten by one).

She also talked about her experiences as a scientist, fishing for and tagging live sharks, and transporting sea turtle nests endangered by the Deepwater Horizon oil spill in the Gulf of Mexico. She also answered the question of what happens when a manatee gets swept up by the Gulf Stream current and ends up in the United Kingdom.

“FedEx has a plane dedicated to moving marine animals,” she said, “which is very cool.”

When students in Ms. Kay’s class were slow to identify an amoeba, Ms. Dore encouraged them to be more inquisitive.

“You’re scientists! Scientists always have opinions,” she said, then laughed, “They’re may not be right, but they always have them.”