The experiment sought to determine the growth patterns of humans’ arm length and head circumference in relation to height from infancy to adulthood. A sample of 25 undergraduate college students were used to obtain measurements of head circumference, arm length and height. These measurements were used to calculated ratios between total height and body part. These ratios were then compared to the ratios calculated from average newborn infants’ measurements. The resulting data suggests that arm length grows isometrically to height and that head circumference grows allometrically to height.
II. Introduction An organism’s shape depends on the relative growth rates of their body parts as they develop. The phenomenon of allometry occurs when an organism’s body parts grow at different rates. The allometry phenomenon is seen in newborn humans whose head is larger in proportion to their body length than is seen in adults. In contrast, isometric growth is the phenomenon whereby an…show more content… Each participant’s height, from the sole of the foot to the top of the head, was measured in centimeters using a meter stick and then recorded. Each participant’s head circumference was measured using cotton string which was wrapped around the widest part of the head from the browline to the lower back portion of the skull. Each participant’s arm length from the shoulder joint to the tip of the middle finger was measured in centimeters using a meter stick. Once these measurements were obtained a ratio of arm length to height was calculated and recorded along with a ratio of head circumference to height for each participant. This measurement procedure was replicated twenty-four times for each of the twenty-four participants. Then, using the ratios obtained for all participants, the ratios were averaged together to obtain the average head circumference to height ratio and the average arm length to height