| Term | Definition |
| fish: endo or ecto | ectotherm |
| fish: circulation | single loop, two chambers |
| fish: respiration | gills |
| fish: reproduction | internal or external |
| amphibians: endo or ecto | ectotherm |
| amphibians: circulation adult | single loop, two chambers |
| amphibians: circulation larve | double loop, three chambers |
| amphibians: respiration adult | lungs and skin |
| amphibians: respiration larve | gills |
| amphibians: reproduction | external |
| reptiles: endo or ecto | ectotherm |
| reptiles: circulation (except crocidiles) | double loop, 3.5 chambers |
| reptiles: circulation: crocidiles | double loop, four chambers |
| reptiles: respiration | lungs |
| reptiles: reproduction | internal |
| birds: endo or ecto | endotherm |
| birds: circulation | double loop, four chambers |
| birds: respiration | lungs (more complex) |
| birds: reproduction | internal |
| mammals: endo or ecto | endotherm |
| mammals: circulation | double loop, four chambers |
| mammals: respiration | lungs (most complex) |
| mammals: reproduction | internal |