How did the 2ND agricultural revolution contribute to European population growth?

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 (<18 years old) and to growing populations (Fig. 6.2) (Bocquet-Appel, 2008, 2011). This conclusion is based on estimates of the proportion of immature skeletal remains, for instance, in the Levant (Bocquet-Appel, 2008) together with analysis of ethnographic data for transitions from hunter–gatherer to farming societies in historical times (Bocquet-Appel, 2011). Similarly, in the North American southwest, as agriculture expanded between 3100 and 1000 BP there were demographic shifts with increases in birth rates (Kohler and Reese, 2014). Contributing to the increase in birth rate was the earlier menarche in Neolithic than hunter–gatherer communities (Hermanussen, 2003).

Agrobiotechnologies: The New Frontier of Sustainable Agriculture

Needless to say, this newest agricultural revolution is largely driven by the advances in biosciences. Modern biotechnology applications, in particular, those related to the various ‘omics’ technologies, speeded up the plant breeding process with respect to conventional plant breeding approaches. Today genetically modified crops are grown in fields at a commercial, global scale. In consequence of this, the biotech crop area has increased from 1.7 million ha in 1996 to 160 million ha in 2011 (Khush, 2012). This trend is expected to continue and even grow considering the latest outstanding improvements in proteomic platforms. The combined action of accelerated gene discovery through genomics, proteomics, and other associated ‘omics’ branches of biotechnology will accelerate the crop breeding improvement programs.

Understanding the key proteomic patterns of a plant growth and development is crucial to achieve progress in crop plants biotechnology. ‘Phenotyping’ at the molecular scale is an emerging field that characterizes plant behavior and quantify features, such as growth and yield, in response to genetic mutation and environmental influences (Zivy et al., 2015). High-throughput phenotyping in plants – the so-called plant phenomics – is an area of emerging research and growing rapidly, which aims to bridge the gap between genomic, physiological, and agronomic approaches.

1.3.2 Industrial revolution

Swiftly on the back of the agricultural revolution came the industrial revolution. This was a period of rapid industrial growth beginning in England toward the second quarter/half of the 18th century (1725–50 AD), which then moved throughout the Europe and the United States. The early part of the revolution observed great leaps of invention, mechanical innovation, and general improvement in labor efficiency, especially on the agricultural playing field among many other sectors of industry. Among many advances in agriculture were the wooden plow, new horse-drawn threshers, grain and grass cutters, cultivators, rakes, and the labor-saving corn shellers and the like. Many in turn were superseded or improved on with arrival of the industrial revolution. Add to this the arrival and application of steam power during this time, which eventually led to the mechanization and industrialization of agriculture. This further led to the commercialization of food and ultimately to the beginning of the food-processing industries (UOR, 2009). Table 1.1 records some of these advances or seminal moments of the agricultural and industrial revolutions. However, during this period, the real coup was undoubtedly the invention of the internal combustion engine in the 1850s. This effectively freed up large agricultural labor forces, allowing millions for the first time to migrate to urban employment (Johnson 1997, 2000).

Table 1.1. Key innovations of the agricultural and industrial revolutions.

Compiled from Tull 1762; de Graffigny, 1898; Fouts, 1921; Ogburn and Thomas, 1922; Morris, 1933; Kuo-Chün, 1958; Olmstead, 1975; Rasmussen, 1977; Powell, 1988; Hills, 1989; Martin, 1991; Fox, 1993; McMichael, 1995; Brunt, 2003; Heldman, 2003; Kauffman, 2003; Nuvolar, 2004; Elliott, 2008; Britannica, 2009.

Migration Versus Acculturation

It has been proposed that the Agricultural Revolution spread from the Near East to South Asia at an average rate of 0.65 km/yr.55 Yet, as in Europe, the topic of the establishment of agriculture in India is plagued with a number of uncertainties. One of these controversial topics is the degree to which plant and animal domestication in South Asia derives from acculturation as opposed to actual movement of people. In other words, one might ask: Was the new more sedentary way of life of farmers introduced into India by sizeable number of migrating people, as part of a mass dispersion wave, or just by the dissemination of ideas including the novel subsistence system into the new land? Most of the available data from different fields support the contention that migration of individuals (not just communication) transmitted domestication and agriculture from the Near East to the Indian subcontinent.

For instance, based on genetic information, an acculturation model by itself would not explain the presence of DNA markers in India known to signal the movement of pastoralists and agriculturists from the Levant. Today the genetic signature of farmers and breeders from the Near East can be traced using Y chromosome–specific (Fig. 7.16) and mtDNA-specific lineages, as well as whole-genome genetic markers.56 Y chromosome type J, for example, has a focus of high concentration within the Fertile Crescent and gradually diffuses along the Arabian Sea coast of Iran and Pakistan, as well as the littoral region of western India, eventually extending into Sri Lanka (Fig. 7.16). This is the expected genetic distribution pattern if haplogroup J males migrated into the subcontinent, disseminating their genes along a coastal route in peninsular India. Specifically, Y haplogroup J2a-M410 exhibits a pattern of gene flow from the Fertile Crescent during the Neolithic period about 10,000 ya into the Indian subcontinent.57 More recent genetic studies suggest that the distribution of Y haplogroups J2a-M410 and J2b-M102 in South Asia indicates a complex scenario of multiple expansions from the Near East to South Asia.58 Maternally derived mtDNA lineages also indicate that a number of the West Eurasian mtDNA haplogroups detected in the Indian populace are attributed to gene flow from the Near East about 9300 ya.59 Whole-genome investigations also detected Eurasian gene flow from Iran and the Near East dating to the times of the Agricultural Revolution.60 Additional recent studies based on specific genes, such as the one that controls lactose tolerance, suggest gene flow from Iran and the Middle East about 10,000 ya.61 It seems that individuals in India carry the same lactose-tolerant gene mutation seen in the Near East and Europeans. Although there is always the possibility that the same gene variant (mutation) occurred in both places independently, it is more likely that a single lactose-tolerant gene originated in the Near East and then was transported to South Asia by migrating farmers. Altogether, these data are congruent with a demographic picture in which the lactose-tolerant mutation dispersed in two directions from the site of origin in the Near East during the Agricultural Revolution. One branch moved into Europe, whereas the other moved into South Asia using a coastal trajectory following the Persian Gulf and the Indian Ocean where the mutation is found. It is highly likely that this lactose-tolerant mutation reached polymorphic levels throughout its distribution range as a result of positive selection generated by the consumption of milk and dairy products made by farmers from domesticates.

Perhaps, the most studied farming community in South Asia is Mehrgarh. The settlement of Mehrgarh is located in the fertile Kacchi Plain of Balochistan in central western Pakistan. The area is on the western rim of the Indus Basin by the eastern foothills of the Suleiman Range (Fig. 7.3). Mehrgarh is one of the earliest agricultural centers in South Asia dating back to 9500 ya. The site is of particular importance because it exhibits a continuous progression of stages from domestication and agriculture to developed civilizations. In addition, Mehrgarh is thought to be a forerunner of a number of Bronze Age urban centers, such as the Indus Valley Civilization, which first appeared in the northwestern regions of South Asia approximately 5000 ya and then spread throughout the subcontinent.63 Mehrgarh had its beginnings as a small farming and herding community. Since its discovery in 1974, about 32,000 artifacts have been unearthed (Figs. 7.17 and 7.18). Habitation in the area extended to 4000 ya, the start of the Bronze Age.64 Although it has been argued that Mehrgarh represents an in situ development of agriculture and domestication, evidence from various fields points to a connection with the Near East and the genesis of farming in the Fertile Crescent.65 One line of evidence stems from studies on lactose tolerance in the subcontinent61 mentioned in the previous paragraph.

1 Introduction

With the onset of the green revolution, agricultural productivity has increased tremendously due to the introduction of better yielding varieties and the use of various agricultural inputs. In general, agricultural inputs are chemical and biological materials used in crop production.

Fertilizers and pesticides attract major attention with respect to inputs in increasing agricultural production. Fertilizer application provides nutrients required for crop growth while pesticide application can significantly reduce plant diseases or insect pests or weeds thus indirectly contributing to an increase in agricultural production. Gradually, the dependence on chemical inputs, mainly the use of chemical fertilizers and pesticides has increased significantly, in all modern agriculture practices. However, in a disturbing trend, the utilization rate of agriculture chemicals is only ~ 35% and the unutilized fertilizers and pesticides are most likely to contaminate soil and water bodies (Zhang, Yan, Guo, Zhang, & Ruiz-Menjivar, 2018). As a result, an alarming level of residues of agricultural chemicals, which are likely to be the result of runoff or unused chemical inputs, were reported to be present in the soil, water, air, and agricultural products in several parts of the world. For example, the buildup of metal contaminants, such as arsenic, cadmium, fluorine, lead, and mercury in agricultural soils was reported to be associated with the vast use of inorganic fertilizers (Udeigwe et al., 2015). Similarly, pesticides were detected in almost all stream water samples at multiple agricultural sites in the USA (Gilliom, 2007) and the residential environments of agricultural communities in Japan (Kawahara, Horikoshi, Yamaguchi, Kumagai, & Yanagisawa, 2005).

In the last century, the use of agricultural chemicals has aided in doubling the production; however, the current need to increase food production keep pressure on the intensive use of fertilizers and pesticides (Carvalho, 2017). There is still a mounting pressure on agriculture to meet the demands of the growing population. As per the United Nations, the world's population will increase by 2.2 billion, reaching around 9.7 billion by 2050 (https://www.un.org/en/development/desa/news/population/2015-report.html). To meet the growing demand for food, excessive and imbalanced use of pesticides and fertilizers continued, and this trend has caused adverse effects on the environment. Although harmful organic pesticides have been replaced by biodegradable chemicals to a large extent, contamination by historical residues and ongoing accumulation still impact the quality of food, water, and environment (Carvalho, 2017). It is essential to develop and adopt sustainable and environmentally friendly agriculture practices, which not only enhance yield but also crop quality and environmental sustainability. With respect to agricultural inputs, pollution impact assessment and pollution prevention/reduction strategies are the most researched areas in the past 3 decades (Zhang et al., 2018), and significant efforts are being continually taken to use harmless sustainable agriculture inputs such as natural fertilizers and biopesticides.

Microalgae can be a great value to agriculture. Many studies indicate the use of microalgae in sustainable and organic agricultural practices (Priyadarshani & Rath, 2012; Sharma, Khokhar, Jat, & Khandelwal, 2012) and still, extensive research is being carried out.

Microalgae are a diverse group of microorganisms that are ubiquitous and found in almost every habitat on earth be it soil, oceans, hot springs or in dessert lands. Microalgae are unicellular or multicellular eukaryotic organisms, however, cyanobacteria that are commonly called blue-green algae (BGA) are also interchangeably referred to as microalgae in this chapter. Microalgae can perform photosynthesis by capturing CO2 from the atmosphere and energy from sunlight. They have a high growth rate and hence produce higher biomass per unit area as compared to other microbes (Gautam, Pareek, & Sharma, 2013, 2015; Hu et al., 2008).

Microalgae are known to possess several functional properties that can make agriculture more sustainable. For example, microalgae have plant growth promoting, insecticidal, and pesticidal activities. Biostimulants produced by microalgae result in improved plant growth and hence enhanced crop performance. Further, microalgae act as biofertilizers and enhance nutrient availability by fixing nitrogen and improving the soil fertility/soil structure. Several microalgae symbiotically interact with higher plants, bacteria, fungi, mycorrhiza, etc., resulting in enhanced growth of the interacting species. Microalgae also find an application in crop protection and combating environmental stress by eliciting defense mechanisms in the plant and suppressing diseases by controlling the growth of pathogens. These beneficial qualities if further exploited in a judicial manner, microalgae can act as a sustainable alternative for wide applications in agriculture (Richmond, 2003). In this review, a detailed overview of a wide range of applications of microalgae, especially as alternatives to synthetic chemicals, in improving the agricultural sustainability has been presented.

The end of current diseases can invite new diseases

The era of infectious diseases began after the agricultural revolution took place, a time when the community began to increase in size and live close to animals by farming and herding. The age of chronic diseases following the Industrial Revolution can be said to have been caused by increased caloric intake and by the growing number of factors detrimental to human health, such as smoking, exposure to chemicals, and stress, in the wake of the drastic change in humanity’s lifestyle. Accordingly, we can say that the pattern of disease is basically determined by the circumstances of the time. The changes that have already started in the contemporary age are increase of the human lifespan, along with a decrease in the fertility rate, an increase in the elderly population, and the weakening of binding power of the family. This shift will change not only the man-man relationship but also the man-machine relationship, thereby evolving into a relationship that is totally different from the past.

The modern society is in the process of undergoing such changes. The successful prevention and treatment of the current chronic diseases will further accelerate the aforementioned changes, and as we have seen in the past civilizations and in the history of diseases, the sooner the society changes, the more likely it is that physical, mental, and social maladjustment will occur, opening up a new era of disease. In the end, to address the contradictory situation in which a new epidemic can occur when the current one is over, it is not enough to simply accept the changes because if the current change will be further accelerated, the possibility of the emergence of a new problem or disease will increase as much.

Therefore, the development of medical technology that can bring about the end of disease has an inherent potential to cause other problems. What will happen if the human capacity enhancement device will allow us to have excellent abilities, and if the strengthening of human abilities will be realized in a discriminatory way based on wealth, power, or specific population groups? Probably, we will no longer accept human abilities as they were given by nature; on the contrary, we will reveal the desire to have superior abilities through the help of such devices, to win the competition with others, and to live longer and healthier lives compared to others. This will undermine the biological laws that have so far relied on natural selection, as well as the moral and ethical foundations of humanity.

People have accepted their given biological abilities and have been living with the conditions that they have received from their parents, but they will likely no longer accept their existence in current form if they can develop superior abilities using artificial means. Competition will also depend more on the abilities enhanced by the strengthening device of the human body than on the natural abilities, which means that we will see greater dependence on machines and devices. Eventually, humanity will gradually transfer its very nature to machines and devices. These changes may lead to problems like identity crisis, loss of self-worth, adjustment disorder, and depression, opening up a new age of illnesses: the Age of Mental Illnesses. Therefore, humanity is now at a critical juncture. It is time for humankind to begin efforts in earnest to prevent such changes from escalating into a crisis of humanity.

Meat and Muscle Foods

Meat consumption by early hunter-gatherers predated the agricultural revolution. Meat and seafood provide a major source of animal proteins in the human diet, notably in Western countries. Meat comes from a wide variety of animal species ranging from poultry to pigs, cattle, sheep, goats and wild game to thousands of species of fish. The meat industry is based on obtaining animals, poultry, and fish from pastures, feedlots, and special intensive production systems, and from extractive industries such as fishing. Processing methods for the various species are different, but they all have been historically developed to ensure that the underlying principles of physiology and biochemistry in the conversion of muscle to meat are optimized. Assessment of meat quality from measurements such as muscle pH, tenderness prediction, color, and microbial contamination are critical for many aspects of the meat industry to provide quality meat products for consumers.