In what way did the agricultural Revolution pave the way for the Industrial Revolution

Population Density and Urbanization

The agricultural revolution in developing countries has produced large resident human populations with the potential for direct person-to-person spread of infection and greater environmental contamination by feces. In addition, animal husbandry has created other cycles for parasite transmission, for example Cryptosporidium spp. in calves. Rapid urbanization, especially in the tropics, is often associated with increased poverty, poor housing and unsanitary conditions. The result is that people may be living in a more fecally polluted environment than in rural areas, encouraging such diseases as amebiasis and giardiasis. Epidemics, such as outbreaks of cryptosporidiosis, may occur when public water supplies become fecally contaminated.1 Cyclospora cayetanensis is transmitted via contaminated produce and contaminated drinking water. The soil-transmitted nematodes Ascaris lumbricoides and Trichuris trichiura are often more common in towns and cities. Overcrowding favors direct transmission of Hymenolepis nana and Enterobius vermicularis, especially in children when levels of hygiene and sanitation are poor.2

Summary

The agricultural revolution is the name given to a number of cultural transformations that initially allowed humans to change from a hunting and gathering subsistence to one of agriculture and animal domestications. Today, more than 80% of human worldwide diet is produced from less than a dozen crop species many of which were domesticated many years ago. Scientists study ancient remains, bone artifacts, and DNA to explore the past and present impact of plant and animal domestication and to make sense of the motivations behind early cultivation techniques. Archeological evidence illustrates that starting in the Holocene epoch approximately 12 thousand years ago [kya], the domestication of plants and animals developed in separate global locations most likely triggered by climate change and local population increases. This transition from hunting and gathering to agriculture occurred very slowly as humans selected crops for cultivation, animals for domestication, then continued to select plants and animals for desirable traits. The development of agriculture marks a major turning point in human history and evolution. In several independent domestication centers, cultivation of plants and animals flourished according to the particular environmental conditions of the region, whereas human migration and trade propelled the global spread of agriculture. This change in subsistence provided surplus plant food that accumulated during the summer and fall for storage and winter consumption, as well as domesticated animals that could be used for meat and dairy products throughout the year. Because these new survival strategies no longer required relocation and migration in search of food, humans were able to establish homesteads, towns, and communities, which, in turn, caused rapid increases in population densities and lead to the emergence of civilizations. This dependence on plant and animal domestication entailed a number of other environmental adaptations including deforestation, irrigation, and the allocation of land for specific crop cultivation. It also triggered various other innovations including new tool technologies, commerce, architecture, an intensified division of labor, defined socioeconomic roles, property ownership, and tiered political systems. This shift in subsistence mode provided a relatively safer existence and in general more leisure time for analytical and creative pursuits resulting in complex language development, and the accelerated evolution of art, religion, and science. However, increases in population density also correlated with the increased prevalence of diseases, interpersonal conflicts, and extreme social stratification. The rise of agriculture and the influence of genetics and culture [gene–culture coevolution] continue to affect modern humans through alterations in nutrition, predisposition to obesity, and exposure to new diseases. This chapter will cover the various regions that adopted early agricultural practices and look at the long-term positive and negative effects of agriculture on society.

6.4.2 Impact on Population and Fertility

The Neolithic or agricultural revolution resulted in a demographic transition and major increases in population [Table 6.1] and population density [Table 6.3]. The population of hunter–gatherers rose at a very low rate constrained by the carrying capacity of the land [see Chapter 4, Fig. 4.1]. The increase in Paleolithic global populations parallels the increase in range as humans migrated from Africa to Asia, Europe, the Americas, and Australia. The increase in the growth rate of human populations increased by as much 60-fold with the Neolithic Revolution [Table 6.1]. “Population, when unchecked, goes on doubling itself every twenty-five years or increases in a geometrical ratio” [Malthus, 1798]. This is seen in the USA with the population rising from 2.5 million in 1776 to 5.3 million in 1800 to 11.1 million to 1825 and 23.2 million in 1850 [US Census, in press]; the population growth being unchecked as more land came into cultivation.

The birth rate of the Natufian hunter–gatherers was low and seemingly declining [Fig. 6.2] [Bocquet-Appel, 2008, 2011]. With the transition to cereal and legume production in the Neolithic Revolution, there was a marked increase in birth rates leading to a concomitant increase in the proportion of young people [