AP Success - AP Biology Conceptual Analysis: Systems Interact - Circulatory

Fish have a unique circulatory system that allows them to extract oxygen from water through their gills. This system is a single-loop system, where the heart pumps the blood to the gills, and from there, it flows to the rest of the body before returning to the heart.

Describe the process of oxygen extraction in fish through their gills.

In a fish tank, the oxygen level suddenly drops. Explain the impact of this change on the fish's circulatory system and its ability to survive.

Predict the possible changes in the fish's circulatory system if it evolves to live in an environment with low oxygen levels.

Some scientists claim that fish have a more efficient circulatory system compared to terrestrial animals due to their single-loop system. Provide reasoning to justify their claim.