Born to Run: Humans will never win a sprint against your average quadruped. But our species is well-adapted for the marathon.
We have a right to conclude that, four our size, humans are pretty poor runners when it comes to chasing a cat that’s trying to avoid a bath. Were we excel is endurance running. Also, we run long distances at fast speeds. Joggers can do a mile in seven and half minutes while top marathoners can do five minute miles together for more than two hours. A quadruped of about 150 pounds takes nine and a half minutes. Good endurance runners are rare among animals.
But what evidence can support the idea that endurance running gave early humans an evolutionary advantage? Long legs and the long stride they enable are helpful to walking as well as to running. But running and walking are mechanically different gaits. A walking person, aided by gravity, acts as an inverted pendulum: the hip swings over the planted foot. A runner bounces along, aided by tendons and ligaments that act as springs, which alternately store and release energy. Also, endurance running requires more stabilization of the trunk than walking does. Members of the genus Homo have substantial gluteus maximus muscles and have large attachments from the hip to the base of the spine. In cave men fossils, the muscle has more limited area of attachment. Chimpanzees are gluteally challenged also. Large butt muscles make for efficient energy transfer during running by stabilizing each hip. But the muscles are not used for walking on level ground.
The shoulder of the chimp is well stabilized, tied to the spine and the head by many strong muscles. In humans, the shoulders are less robust because when we walk, our shoulders don’t move much. When we run, because of the loose attachment, the shoulders rotate strongly one way while the hips rotate the other, which keeps us in balance. We can also swing the upper body without rotating the head, so we can see where were going. Homo also has several “antibobblehead” adaptations that apes and cavemen lack. The first is a modification of semicircular canals, the organs in each ear that tell the brain which way is up. Three canals sit at right angles to each other in each inner ear. Two are enlarged in Homo, and the size makes it easier to sense, and to counteract, a moving head. An elastic ligament that runs from a ridge at the base of the skull to the base of the neck also damps the bobbing effect. Analougous ridge structures, to which damping ligaments can be attached, occur in dogs and horses, but not in the chimp. Bramble and Lieberman’s analysis makes corrections to the scientific picture of early humans. Our ancestors might have ranged across large distances in the heat of African dessert in relatively short spurts of long-distance running, as well as walking. They may have been trying to maximize the chance of encountering carrion before other scavengers did, or perhaps they were adapted to running down prey before spear throwers or bows were invented.
Scientific Article Analysis
Topic: Genetic traits in sexual organisms.
Find an article that discusses any genetic trait that is presented in any sexual organism; you can talk about particular characteristics, genetic defects, particular adaptations that enhance the survival of an organism, etc.
Read the article and type a one paragraph summary of the findings. Post your work on the Biotic-Blog (link), don’t forget to log in with your Gmail account.
Analysis
After the paragraph, identify the approach the researcher or group of researchers took to make their discovery.
· Was the article you selected an example of discovery science or hypothesis based science? Explain
My article is discovery science because we discovered the qualities of the tendons and shoulders of the chimps, the homo, and the cavemen.
· What importance does the research or findings have for humans?
It gives a good adaptation for survival and health.
Article Written by: Adam Summers
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