Evolution Lab Essay

756 WordsFeb 11, 20154 Pages
B. (b) 1. 2. How does the human skull differ from the chimpanzee skull in this respect? The parietal bone is elongated and compressed, as opposed to the rounded human parietal bone. 3. Compare the shape and position of the occipital bones in the human and chimpanzee skulls. How does the difference in the position of the foramen magnum, a large opening in the base of the skull for the spinal cord, correlate with the posture and stance of the two organisms? The occipital in humans is rounded; in the chimpanzee, it has a prominent ridge for attachment of neck muscles. Its position is lower (more ventral) in the chimpanzee. In the human, the foramen magnum is placed almost in the bottom center of the skull; in the chimpanzee, the opening is well to the rear. Humans walk upright, and chimpanzees use all four limbs for walking. 4. Compare the slope of the frontal bones of the human and chimpanzee skulls. How are they different? a. In the human, the frontal bone is rounded; in the chimpanzee, it is sloped backward. b. The supraorbital ridge of the chimpanzee is thicker. 5. What is the position of the mouth and chin in relation to the profile for each skull? What effect has the evolutionary change in the positions of these bones had on the shape of the face?. Humans do not have a muzzle; chimpanzees do. The human face is flattened 6. Examine the teeth in the adult human and chimpanzee skulls. Are the shapes and types of teeth similar in both? Not really. Human teeth are small; chimpanzee molars are larger and flatter, and the canines are much longer B. (c) Vertebrate Embryos Q1. (a)List five similarities between the two embryos. a. General shape of presumptive head b. Shape and orientation of limb buds c. Presence and shape of the tail d. Appearance of somites on dorsal surface e. Placement of the eyes in relation to the rest of the head (b)Why might a chick embryo and a pig

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