Basically the title. They’re going to encounter animals they’ve never seen before, or notice a complete lack of familiar animals. They’re going to notice the none of the plants are the same, and that there aren’t any domesticated plants other than what they may be carrying. They might try to go back the way they came and find it impossible.
In Arizona you can go from Sonoran Desert to forest tundra in as little as 45 miles. Anyone who grows up in Phoenix and vacations in Flagstaff knows the sensation of feeling like you’ve entered a different world several times along the way.
This is a fun read: https://www.desertmuseum.org/desert/habitats_sonora.php?print=y
Paul Sorvino’s misguided plan was well intended, but doomed to fail.

And then there’s the poor schmuck who wandered in from the holodeck.

Couldn’t grasp such radical notions. The rest of the tribe would likely react about the same.
“Is this a two-parter?”
“No, we don’t do those.”
“What do we do with this B-plot guy that saw the ship? We’ve got a whole thing going on with his story that could go to some interesting places. How should we handle that?”
“Just kill him.”
“Should we re-write it and just take that part of the plot out?”
“Nah, just have him off himself or something.”
Picard wanted them dead, so they got a good deal.
I had a similar realization when rewatching 03x04 Who Watches The Watchers. Those Mintakans would eventually realize they are unrelated to every other life form on the planet.
They might even have legends of a man in the sky promising them a new world, now a theory to be wholly supported by the biological record x_x


