Chapter 13: Evolution: Today and Tomorrow
Chapter Summary
Focus of the chapter:
- Evolutionary forces
- Environmental shifts
- Human evolution
Global warming, the increase in the earth’s temperature, is everywhere in the popular media today. Strong scientific evidence exists for changes in the earth’s temperature and the resulting climatic changes.
Most of the changes in the earth today are anthropogenic, or caused by human actions. Increasing usage of fossil fuels, reliance on manufacturing techniques emitting greenhouse gases, and deforestation, among other practices, have contributed to the rise in temperature.
Human population growth is at an all-time high, with over 6 billion people on the planet today. Much of the population explosion has occurred in Africa and Asia, continents that lack the resources to handle the variety of crises caused by the size of their populations.
Infectious illnesses have increased with population size and density. Nutri tion al crises in the form of famine and overnutrition have also resulted.
Obesity and allergies are two costs of shifts in human culture. Increasing height and lifespan are two benefits.
Human evolution continues today and can be seen in such mutations as the sickle-cell gene and G6pd. Changes in the human skull, face, and dentition have also been documented. Although we cannot predict the exact nature of human change, we can be sure it will be influenced by energy consumption, population size, and global climate.
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