Population 2 would have more adaptations for salt water because they live in habitats with higher salt levels. Snails that can handle salt better are more likely to survive and have babies in this environment. This means that over time, more and more snails in Population 2 will have features that help them live in saltier water...
such as thicker shells, enhanced mechanisms for regulating salt intake, and increased tolerance to high salinity levels.
On the other hand, Population 1, which lives in habitats with lower salt levels, would not have as strong of a selection pressure for salt tolerance. As a result, the snails in Population 1 may not have as many adaptations for salt water as those in Population 2.
This scenario is an example of natural selection, where environmental factors drive the evolution of different traits in populations of the same species. Over time, the snails in Population 2 may become better suited to their high-salinity habitats, while the snails in Population 1 may maintain their adaptations for low-salinity environments.
use simpler terms
Sure! In simple terms, snails in Population 2 that can handle salty water better are more likely to survive and have babies. This leads to more and more snails in Population 2 having features that help them live in saltier water, like stronger shells and better ways to handle salt.
In contrast, snails in Population 1 don't need to deal with as much salt, so they may not have as many features to help them in salty water.
This shows how living in different environments can cause snails to evolve different traits over time.