BIO SCI 94 Lecture Notes - Lecture 15: Actinopterygii, Mesozoic, Coelurosauria

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Nancy Burley

Document Summary

Notochord - flexible rod running along dorsal axis of body. Pharyngeal slits- allows water to pass through. Invertebrate chordates includes 2 subphylum: cephalochordata and urochordata. Vertebrates have cranium (skull that encloses brain)and vertebrae (cartilaginous body that protects spinal cord) Brain is separated in 3 groups: forebrain, midbrain, hindbrain. 2 pairs of skeletal rods (cartilage) that supported gills. Gill arches developed over time with jaws. Air-filled swim bladder (gas bladder for buoyancy) A key transition to land: limbs to move on land. Tetrapods = vertebrates with two sets of limbs containing digits (ex. toes) They hypothesis that walking limbs evolved from from fish fins is supported by fossil record and molecular evidence. Amniotes: vertebrates that produce an amniotic egg. Temporal fenestra: hole in side of skull for muscle attachment. Theropod hypothesis: origin of birds from maniraptors. Birds evolved about 150 million year ago. Emerged in synapsid lineage shortly after dinosaurs (220 million years ago)