BIO 182 Chapter Notes - Chapter 44.4-44.5: Agnatha, Cambrian Explosion, Chondrichthyes
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Vertebrae hard segments that form the skeleton. Vertebrates all have craniums that protect the brain. Fish: hagfish and lampreys jawless fish. Have a vertebral column but no vertebrae: chondrichthyes cartilaginous fish. Have jaws and skeletons made of cartilage. Only teeth are made of calcium phosphate. Include rays and sharks: osteichthyes bony fish. Have a cranium, jaw, and bones made up of calcium phosphate. Swim bladder that allows them to control their buoyancy. Kidneys allow them to live in waters with varying ranges of salinity. Each phyla that transitioned to land did so independently of one another. Tetrapods four-limbed vertebrates: transition to land. Lobe-finned fish bony fish with muscles in their fins. Can survive dry periods by burying themselves in the mud. Lungfish developed a way of breathing on land. Amniotes developed terrestrial eggs to allow for reproduction on land: some have lost their limbs (snakes, amphibians. Generally have aquatic larva and terrestrial adults.
