Fill in the table “Comparative characteristics of fish classes” (Cartilaginous, Bone, Bone-cartilaginous)
| November 13, 2020 | Education
| Comparison criteria | Fish classes | ||
| Cartilaginous | Bone | Bone-cartilaginous | |
| Body shape | Torpedo (sharks) or flattened (rays) | Fusiform, elongated or flattened | Torpedo |
| Skeleton | Cartilaginous (no gill covers) | Bony (gill covers available) | The skull is bony, there are gill covers, the notochord is preserved throughout life, the rest of the skeleton is cartilaginous |
| Respiratory system | Gills | Gills (lungs formed from the swim bladder in lungs) | Gills |
| Lifestyle | Active predators (sharks); bottom predators (rays) | Herbivores, predators | Predators (mostly benthic) |
| Coloration | Dark above, light below | Varied, depending on lifestyle and habitat (sometimes very bright) | Dark above, light below |
| Scales | Plakoid (small scales, each has a denticle directed backward) | Bony (scales are located, overlapping each other, grow all life, form annual rings) | Bone (large scales, form pyramidal protrusions) |
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