Environmental Problems, Their Causes, and Sustainability 1

A continent ages quickly once we come.ERNEST HEMINGWAYThis chapter addresses the following questions:■■■What major beneficial and harmful effects havehunter–gatherer societies, agricultural societies,and industrialized societies had on the environment?What might be the environmental impactof the current information and globalizationrevolution?What are the major phases in the history ofland and wildlife conservation, public health,and environmental protection in the UnitedStates?What is Aldo Leopold’s land ethic?2-1 CULTURAL CHANGESAND THE ENVIRONMENTWhat Major Human Cultural Changes HaveTaken Place? Agriculture, Industrialization,and GlobalizationSince our hunter–gatherer days we have undergonethree major cultural changes that have increased ourimpact on the environment.Evidence from fossils, DNA analysis, and studies ofancient cultures suggests that the earliest form of thehuman (Homo sapiens) species was Homo sapiens idaltu,which existed about 160,000 years ago. The latest versionof our species, Homo sapiens sapiens, has beenaround for only about 60,000 years. Thus the variousversions of Homo sapiens have walked the earth for lessthan an eye blink of the estimated 3.7-billion-year existenceof life on this marvelous planet. We are theplanet’s new infants.Until about 12,000 years ago, we were mostlyhunter–gatherers who typically moved as needed tofind enough food for survival. Since then, three majorcultural changes have occurred: the agricultural revolution(which began 10,000–12,000 years ago), the industrial–medicalrevolution (which began about 275 yearsago), and the information and globalization revolution(which began about 50 years ago).These changes have greatly increased our impacton the environment in three ways. They have given usmuch more energy and new technologies with whichto alter and control more of the planet to meet ourbasic needs and increasing wants. They have also allowedexpansion of the human population, mostly becauseof increased food supplies and longer life spans.In addition, they have greatly increased our resourceuse, pollution, and environmental degradation.How Did Ancient Hunting-and-GatheringSocieties Affect the Environment? LivingLightly on the EarthHunter–gatherers had a fairly small impact on theirenvironment.During most of their 60,000-year existence, Homo sapienssapiens have been hunter–gatherers. They survivedby collecting edible wild plant parts, hunting, fishing,and scavenging meat from animals killed by otherpredators. Our hunter–gatherer ancestors typicallylived in small bands of fewer than 50 people whoworked together to get enough food to survive. Manygroups were nomadic, picking up their few possessionsand moving seasonally from place to place to findenough food.The earliest hunter–gatherers (and those still livingthis way today) survived through expert knowledgeand understanding of their natural surroundings.Because of high infant mortality and an estimated averagelife span of 30–40 years, hunter–gatherer populationsgrew very slowly.Advanced hunter–gatherers had greater environmentalimpacts than those of early hunter–gatherers.They used more advanced tools and fire to convertforests into grasslands. There is also some evidencethat they probably contributed to the extinction ofsome large animals. They also altered the distributionof plants (and animals feeding on such plants) as theycarried seeds and plants to new areas.Early and advanced hunter–gatherers exploitedtheir environment to survive. But their environmentalimpact usually was limited and local because of theirsmall population, low resource use per person, migrationthat allowed natural processes to repair most ofthe damage they caused, and lack of technology thatcould have expanded their impact.What Was the Agricultural Revolution?More Food, More People, Longer Lives,and an Increasing Ecological FootprintAgriculture provided more food for more peoplewho lived longer and in better health but alsogreatly increased environmental degradation.Some 10,000–12,000 years ago, a cultural shift knownas the agricultural revolution began in several regionsof the world. It involved a gradual move from usuallynomadic hunting-and-gathering groups to settled agriculturalcommunities in which people domesticatedwild animals and cultivated wild plants.Plant cultivation probably developed in manyareas, some including tropical forests of SoutheastAsia, northeast Africa, and Mexico. People discoveredhow to grow various wild food plants from roots or tubers(fleshy underground stems). To prepare the landhttp://biology.brookscole.com/miller1421