Savanna Hypothesis

5a. Dracunculus medinensis, commonly known as the Guinea worm, is a human parasite. It enters the body through water fleas, but when the fleas reach the digestive tract, the fleas are killed and the worm larvae are not. Over the course of about a year, the larvae grow and develop into full-fledged worms carrying thousands of new larvae. The worms travel to the skin and expel acid to burn their way out. The burning sensation causes human hosts to feel the urge for cold water to ease the pain. However, this is host manipulation because the cool water triggers the worms to release the milky substance carrying the larvae. This allows the Guinea worm to continue the life cycle with a new generation of larvae.
5b. Hymenoepimecis argyraphaga is
Both the “savanna hypothesis” and the “aquatic ape hypothesis” attempt to explain the bipedalism of humans—our tendency and ability to walk upright, on two feet. According to the savanna hypothesis, our ancestors left the forests in Africa for the plains. The males hunted and needed to survey the horizon and walk a great distance. So, they began walking on two feet to better accommodate this need. This hypothesis also explains our larger brain size since smarter individuals were more adept at making and using tools. On top of this, it also states that we lost our hair because we overheated from all the hunting. However, this theory focuses on the males; in reality, the women and children should shape evolution as well. That’s when Elaine Morgan postulated a different idea, one that seemed to make more sense. After all, many quadrupeds cover distance much faster than humans; this provides much controversy on the distance coverage part of the savanna hypothesis. In addition, females have less hair than males, so it wouldn’t make sense that the evolutionary cause for hair loss is overheating due to hunting. It also doesn’t make sense that we’re the only land mammals without hair, despite the other animals hunting for food as well. That is better explained in Morgan’s aquatic ape hypothesis, which suggests a semiaquatic ancestor. This theoretical ancestor spent large amounts of time living and hunting in water, developing the ability to hold its breath and dive underwater to obtain food. Predator avoidance was easier given that the species could survive in and out of water. Bipedalism would have evolved to help go into deeper water without having to submerge the head. Having semiaquatic ancestry also may explain our downward-facing nostrils, a trait shared with a modern semiaquatic species that stands on two feet in water. The aquatic ape theory also shows our lack of hair as an adaptation to help us in the water. Other hairless mammals also live in the water, like