Chapter Study Outline

1. The Forces of Change: A Warming Planet, Increasing Population, and Shifting Technology

a. Global Warming

i. Increasingly prevalent in media discussions today

ii. Refers to the increase in average earth temperature

iii. Has occurred during other times in the earth’s history

iv. Current warming trend due at least in part to human activity (anthropogenic)

v. Technological changes: use of fossil fuels, emission of gases from manufacturing

vi. Main cause: trapped CO2

vii. Results in climate change

(1) Shifting patterns of precipitation and dryness, affecting food resources

(2) Rising sea levels due to melting glaciers, threatening coastal areas

b. Human Population Growth

i. Climate extremes result in health crises from malnutrition.

ii. Health risks will double by 2030, as predicted by the WHO.

iii. Population growth, particularly in Africa and Asia, is the largest factor.

iv. These areas have the least resources to deal with the crises.

v. Today more than 50% of the world’s population lives in cities.

vi. Lack of vegetation, concentrated heat from roads cause higher temperatures.

vii. Concentration of people results in high levels of waste products.

viii. Increasing crowding provides new reservoirs for infectious diseases.

ix. Technology has increased human longevity through improvements in sanitation, medical care, and quality of life.

x. Costs of longer life include loss of bone mass, heart disease, and so on, as well as negative effects on Earth’s biodiversity.

c. The Nutrition Transition and Allergies on the Rise

i. Height and weight have increased in the past hundred years.

ii. Shift to a high-fat, high-carbohydrate diet; obesity as an epidemic.

iii. Extra weight causes cardiac, circulatory, metabolic disorders.

iv. Reactions to food, modern environment are becoming more prevalent.

v. Allergies are associated with a changing world, especially industrialization.

vi. Causes include genetics, but diet, overuse of antibiotics, and environmental pollutants are also factors.

vii. Hygiene hypothesis argues that cleanliness decreases endotoxins, which help decrease allergies.

2. Our Ongoing Evolution

a. Humans have affected other species’ evolution and continue to do so today.

i. Insects, bacteria, fish are only a few examples.

b. Changes in human skull, face, and dental morphology have been documented around the world.

i. Are occurring in a short amount of time

c. Genes such as the sickle-cell gene, G6pd, HIF2a, and others confer selective advantages on humans in certain environments.

d. Genetic studies are advancing understanding of the mechanisms that cause HIV/AIDS.

3. Who Will We Be Tomorrow?

a. Evolution, even in humans, will continue.

b. Left unchecked, human population growth, energy consumption, and global climate change will likely cause new selective pressures.

c. Humans will need to find ways to adapt to these new pressures— through culture or biology.