Please answer all questions
1. Provide a case against the Multiregional Model of the evolution of Homo sapiens.
2. Explain how the decline in genetic diversity with distance from Africa supports the Out of Africa hypotheses.
3. What characteristics of Sahelanthropus tchadensis exclude it from being considered human?
4. What characteristics of Sahelanthropus tchadensis exclude it from being considered human?
5. Should Homo erectus be considered human? Defend your answer.
6. Describe two relic structures in man’s anatomy that reflect our common evolution history with other animals.
7. What does Shubin mean by the phrase “Your Inner Fish”? How do vestigial or maladaptive features enhance his message?
- Several theories oppose the multiregional model of the evolution of Homo sapiens. One such theory is based on the significant similarity in humans all over the world. If evolution from different Homo erectus groups could have happened, it means that humans would have been very dissimilar, which is not the case.
- Considering that humans originated from one place, it means that different people stayed at that place and as they mated, diversity was encouraged. However, as they moved further and further, they interacted with more or less the same people thereby giving little rise to diverse offspring.
- Most of the human fossils had a sizeable brain, averagely bigger than that of a chimpanzee. However, the Sahelanthropus tchadensis had a smaller brain than a chimpanzee, therefore disqualifying it from being human. The brow ridges of the Sahelanthropus tchadensis were low, and the hominid also had a sloping face.
- Homo erectus should be considered human because of the physical features that the hominid displayed. Firstly, the Homo erectus had a developed brain, a characteristic that enabled the hominin to intellectually make decisions, such as lighting a fire and cooking. Besides, the hominin could walk upright, and the upper body was in proportion with the lower body as it is with humans today.
- Appendix- Plant eating mammals have the appendix, which is essential in the digestion of their food. Since humans have appendices but use them, it means they were once part of the ape family. Coccyx/tailbone- humans have this part on their body as a vestigial structure. Apes and chimpanzees also have the same tailbone meaning that humans and apes were once in one family.
- During the formation of an embryo, some features of the embryo resemble those of a fish, like the gills and the tail. Therefore the phrase ‘Your inner fish’ may mean evolution took place, and that is why humans, as well as other mammals like whales, are having vestigial structures and maladaptive features.