AGRC1020 Lecture Notes - Lecture 16: Oviparity, Cave Painting, Paleoanthropology
30 Jul 2018
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It provides skeletal support throughout most of the length of a chordate. In many species, the tail is greatly reduced during embryonic development: the tail contains skeletal elements and muscles. It provides propelling force in many aquatic species. Lancelets: lancelets (cephalochordata) are named for their bladelike shape, they are marine suspension feeders that retain characteristics of the chordate body plan as adults. In other cambrian rocks, paleontologists have found fossils of even more advanced chordates, such as myllokunmingia: myllokunmingia had parts of a skull but lacked vertebrae and hence is not classified as a vertebrate. Origins of bone and teeth: mineralisation appears to have originated with vertebrate mouthparts, the vertebrate endoskeleton became fully mineralised much later. Silurian and devonian periods (444 to 359 million years ago: three lineages of jawed vertebrates survive today: chondrichthyans, ray- finned fishes, and lobe-fins. Ray-finned fishes and lobe-fins: the vast majority of vertebrates belong to a clade of gnathostomes called.
