BIO 200 Lecture Notes - Lecture 21: Spinal Cord, Tiktaalik, Necturus
27 Jun 2015
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Vertebrate traits: heads: anterior skull covers large brain (sensory organ, endoskeletons: cartilage or bone, supported by vertebrae, spinal cord: communication between brain and body, allows for larger size and flexible movement. Internal organs: brain, heart, liver, kidney, etc: suspended in a coelom, endocrine glands: produce hormones, circulatory system: pumps blood through body, muscular heart, critical for large size. Jawless fishes: hagfish and lampreys: hagfish are the sister taxa to the vertebrates, weak circulatory system, three heart-like organs, brain-like organ protected by skull-like structure. Fish: over half of vertebrates are fish. Jaws: ability to catch and eat large and active prey, paired appendages, fins at shoulders and hips, aid in stabilization and propulsion. Internal gills: extract oxygen from water, single loop blood circulation, blood travels in a single circle, heart to gills to body to heart (repeat, nutritional deficiencies, unable to synthesize three amino acids, must consume amino acids in food.
