1. Discuss why most mollusks would have an open circulatory system but why cephalopods (octopus, squid, and nautilus) would have a closed circulatory system. Consider the circulatory needs of the predator as opposed to the sedentary filter feeder or the herbivore.
2. Discuss the improvements in efficiency from the one-circuit heart of the fish to the partially separated circulation in most reptiles to the completely separated two-circuit heart of birds and mammals. Consider activity levels, warm-bloodedness, and similar functions that depend on oxygen and nutrient delivery.
3. Consider the size, shape, and structure of the human heart and why it has a thicker wall on the left side, which delivers blood to the systemic circuit, as opposed to the right side, which sends blood only to the nearby pulmonary circuit.
4. Discuss the actions of the valves and why valvular
damage can cause heart murmurs, varicose veins in the legs, and
even death.