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Unformatted text preview: ls) and uric acid (turtles, lizards, snakes, crocodiles, birds). Forelimbs modified for flight. The light bones of the anterior limbs are elongated, reduced in number, resulting from fusion and always containing numerous air cavities (pneumatized). Epidermis covered with feathers. Character states are modification present (P) or absent (A). Gizzard. The stomach of some vertebrates has an area where food is broken down by a thick muscular wall and by stones that it sometimes contains. Possible states for this character are present (P) or absent (A). Hair (or Fur). Possible states are: present (P) or absent (A). Jaws. Jaws are used for biting, cutting and/or orienting a prey before it enters the digestive tract. Vertebrates with jaws are gnathostomes; vertebrates without jaws are agnathan. They may be either present (P) or absent (A). Lungs and derived structures (swim bladder). In many vertebrates, the respiratory exchanges occur mainly in the lungs, but some aquatic animals use structures derived from the lungs (swim bladder) for flotation purposes. Character states for lungs and derived structures are present (P) or absent (A). Notochord (persistent or present at certain stage of development). An elongated cellular and cartilaginous rod‐like structure found dorsally in chordate embryos. It sometimes persists into adulthood and provides axial skeletal support. States are notochord present (P) or absent (A). 57 Lab3 ‐ Vertebrate phylogeny Number of digits on hind limb. Collect your information from diagrams and specimens in the lab, as well as outside reference sources. If no hind limbs are present, the number of digits is zero. Possible character states are 0, 4 or 5 digits. Number of sacral vertebrae. The sacral vertebrae (the hip) act as an attachment point for the pelvic girdle (posterior limbs). Possible states correspond to the number of vertebrae: 0, 1, 2+. Occipital condyle. A post‐cranial protrusion (or bulge) that acts as the articulation point for the spinal column. Animals that do not have a neck (no head movement in relation to the thorax) do not have occipital condyles. Animals that do move or bend their heads have one or two occipital condyles. Possible states for this character are: 0, 1 or 2 occipital condyles. Paired appendages (fins or limbs). Paired organs projecting from the axial skeleton, usually involved in locomotion. These may or may not contain skeletal elements. The states for this character are: present (P) or absent (A). Paired limbs with tarsi and carpi. The tarsi and carpi are the bones that form the ankle and the wrist, respectively. Please note the following states: present (P) or absent (A). Shell. The body may either be enclosed by dorsal carapace (composed of an outer keratinous layer and an inner layer of bone) and a ventral breastplate (plastron) or a dorsal covering of keratinous and bony plates. The possible states for this character are shell present (P) or absent (A). Skeletal tissue. The skeletal tissue may b...
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This note was uploaded on 02/04/2014 for the course BIO 1130 taught by Professor Fenwick during the Fall '08 term at University of Ottawa.

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