During the evolutionary progression of vertebrate circulatory systems, the structural organization of the heart evolved from a simple single-circuit pump to a completely divided double-circuit system. Which statement accurately describes an evolutionary trend observed across vertebrate heart structures?
- Homoiothermic vertebrates, such as birds and mammals, evolved a four-chambered heart that completely prevents the mixing of oxygenated and deoxygenated blood.Answer
- BAmphibians evolved a two-chambered heart comprising a single atrium and one ventricle, restricting them to low metabolic activity.
- CBony fishes evolved a three-chambered heart with two distinct atria and one ventricle to pump blood directly to the lungs.
- DReptiles evolved a heart with four completely separated chambers across all living orders, functionally identical to mammalian heart anatomy.
Answer
Homoiothermic vertebrates, such as birds and mammals, evolved a four-chambered heart that completely prevents the mixing of oxygenated and deoxygenated blood.
The evolution of the vertebrate heart demonstrates a progression from single circulation in fish (two chambers) to partial double circulation in amphibians and reptiles (three chambers), and finally complete double circulation in birds and mammals (four chambers). The four-chambered heart has two separate atria and two separate ventricles, preventing the mixing of oxygenated and deoxygenated blood to meet high metabolic requirements.
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Key Concept
Evolutionary Trends in Vertebrate Circulatory Systems