BIO 101 Lecture Notes - Lecture 24: Echidna, Reptile, Invertebrate
Document Summary
Chordates include three clades: the lancelets (intervertebrate, the tunicates (intervertebrate) (other than the four distinctive structures, the gill slits is the only thing in common with chordate, the craniates (vertebrate) Include chordates that have a skull that encloses a brain. Vertebrates: animals in which the embryonic notochord is replaced during development by a backbone. Vertebral column: a backbone composed of bone or cartilage (resembles bone, but is more flexible) Hagfish: craniate chordates that have no backbone, produces slime, plates of cartilage around the brain (kind of like a skull) Vertebrate groups: lampreys, cartilaginous fishes, bony fishes. Lampreys: parasitize fish (food and blood, jawless, have a large rounded sucker that surrounds the mouth, spinal cord is protected by cartilaginous segments: vertebrate, live in both fresh and salt waters. Marine forms must return to fresh water to spawn. Spawning: to reproduce, female release eggs into water, male release sperm into water, external fertilization.
