Explain that when an environment changes, naturally or from human causes, the organisms that can survive there may also change, since some can adapt or move while others cannot.
Environments do not stay the same forever. A river might dry up, a forest might burn, a new road might cut through a field, or a lake might slowly shrink each year. When an environment changes, it may no longer be able to support all of the same organisms it used to.
Some plants and animals may be able to move to a new area or already have traits that help them adjust, while others that cannot move or adjust may struggle to survive, or disappear from that area altogether. Plants, in particular, cannot move away from a changing environment at all.
Mastery looks like: They explain, using a specific scenario, how a described environmental change affects which organisms can continue to live there.
Common stumbles: Assuming all animals can simply move away from a change with no real difficulty, or forgetting that plants generally cannot move at all.