However evidence elsewhere in the literature exists that suggest possible mechanisms. Using data from Zimbabwe Hoddinott and Kinsey find that children exposed to the 1995 drought while they were one to three years are shorter. Alderman et al. find that short run height deficits from exposure to civil war or drought in Zimbabwe during childhood are still apparent at adolescence and reduces readiness for school and school progression. Moreover in an attempt to cope with shocks, parents may induce their children to leave school for work. De Janvry et al. find evidence of state-dependence in enrollment rates among young children in rural Mexico which suggests that short-run impacts on school enrollment may have large medium-run to long-run consequences on enrollment status and accumulated years of schooling. My findings lend some support to this as I find that in the provinces most affected by the drought children who were exposed to the drought were still less likely to be enrolled in school five to six years after the drought. The findings outlined in this paper also suggest that the current effort to increase rainfall insurance in developing countries may have large benefits on the skills and productivity of future generations.The transition from hunting and gathering to agricultural subsistence, characterized by the development of human control over the reproduction and evolution of plants and animals,square black flower bucket wholesale has long been interpreted as the most significant shift in human interaction with the natural world .

A general characteristic of this transition is the reduction in dietary breadth and dependence on one or a few highly productive domesticated plants that may lead to associated nutritional deficiency and a greater proportion of dietary carbohydrates relative to protein . Such nutritional changes are a component of the dominant paradigm of our understanding of the transition to agriculture, that it engendered a negative impact on human health which was exacerbated by sedentism, greater population density and frequencies of infectious disease, and the increased prevalence of zoonotic diseases associated with domestic animals . A decrease in stature in the transition from hunting and gathering to farming has been documented in a wide range of contexts ; however, many studies treat the transition as a rapid and discrete dichotomous contrast between foraging and farming subsistence strategies. This masks the complexity of the underlying social and biological transitions . In many regions, foragers are known to have extensively managed wild plants prior to full agriculture, and the process of plant domestication and the associated shift to crop farming is associated with hundreds or thousands of years of cultural and domesticate coevolution, during which many farming populations practiced mixed subsistence strategies and continued hunting and foraging. These trends suggest that dichotomous contrasts between foragers and farmers may be problematic, and the phenotypic consequences of the transition to agriculture should be considered using very deep diachronic skeletal series that document human biological change over long-time spans within the late Pleistocene and Holocene.

Studies adopting this approach demonstrate that in some regions, initial declines in health indicators and stature are followed by a recovery , or conversely that body size decreases predated the origins of agriculture . Recently an innovative study integrating estimates of the genetic component of stature based on ancient DNA and direct measures of human stature from European skeletal remains, demonstrated that a decline in stature between the Upper Paleolithic and Mesolithic and subsequent increase between the Neolithic and Bronze Age, was supported by both lines of evidence . An important aspect of the domestication of animals is what has been termed the Secondary Products Revolution, the use of domestic animals for byproducts such as milk, wool, or as a source of labor for agricultural subsistence . A potential barrier to the consumption of milk among most human populations is the inability to digest the milk sugar lactose. The production of secondary milk products such as yogurt, where fermentation reduces the levels of lactose, or cheese, which separates lactose in whey , buffer adverse side effects of lactose consumption and involve a rich array of cultural practices for the reduction of milk . Human infants typically produce the intestinal enzyme lactase to enable digestion of dietary lactose in breast milk but lose this ability during early childhood. There are a variety of single-nucleotide polymorphisms in the gene promoting lactase persistence that demonstrate independent convergent evolution in the ability to digest lactose among some European and Eastern African populations , and there has also been selection for lactase persistence in other regions , in each case indicating an adaptive response to cultural shifts toward dairying. Milk is a source of insulin-like growth factor I but IGF-I is degraded during the production of cheese or yogurt.

It has been proposed that lactase persistence and milk consumption during childhood development and adulthood elevate circulating concentrations of IGF-I, which coordinate the timing of life-history events and promote skeletal growth . In two recent papers, we have hypothesized that many of the phenotypic and health consequences of cultural and dietary change in the Holocene can be linked through energetic tradeoffs, which provide a diversity of phenotypic outcomes in different contexts , and an adaptive shift toward milk consumption and lactase persistence may have mediated nutritional stress and “turbo-charged” growth in regions where chronic nutritional deficiency was mediated by dairying . There is some evidence that increases in stature in southern Sweden occurred during the early Bronze Age due to a consolidation of an agro-pastoral economy, rather than the onset of farming . Collectively, these papers support what we term the Lactase Growth Hypothesis , which suggests that lactase persistence and the ability to digest primary dairy products and lactose increased available dietary energy, shifted the energetic biology of human growth, and fueled regional differences in human body size.The earliest evidence for the transition to agriculture occurs in the Levant region of the Eastern Mediterranean. The late Epipaleolithic “Natufian” of the Levant is often interpreted as providing the earliest archaeological signature of the transition due to the extensive exploitation of wild grains and grindstones, stone architecture, and a variety of organized site structures , including the earliest evidence for bread . Many of the features associated with the Natufian are actually found at Epipaleolithic sites as early as 20 kya representing long term trends toward sedentism, architecture, and exploitation of grain among hunter-gatherers ; however, there is evidence of intensification of cereal cultivation associated with the Younger Dryas cooling at approximately 13,000 B.P. . The PrePottery Neolithic A period shows the first evidence for larger human settlements with permanent architecture and intensive use and storage of grains by 11 kya . The Neolithization process was in full swing by 9 kya , yet the importance of hunting and gathering to subsistence in these periods remains evident ,plastic square flower bucket and illustrates the complexity of subsistence transitions in this region. While these late Pleistocene and early Holocene cultures in Southwest Asia reflect the earliest transition to farming, it is now well established that agriculture and the domestication of animals originated independently in different regions of the world at different times throughout the first half of the Holocene , while agriculture also spread through migration and cultural diffusion into other regions including Europe . The adoption of agriculture in Europe was geographically and temporally variable. In Southern Europe, the process occurred fairly rapidly between 8 and 7.5 kya as climatic conditions were favorable for Southwest Asian domesticates, and was driven by a combination of demic diffusion and cultural change by existing Mesolithic hunter-gatherer populations . The adoption of agriculture in Central Europe was primarily driven by demic diffusion from the Balkans , but there is evidence that this process was more gradual because of the rich aquatic resources in river systems such as the Danube , and possible challenges of establishing agriculture based upon Southwest Asian crops in more northern climes.

The Linearbandkeramik culture, representing the early Neolithic of Central Europe, marks a crucial period in the expansion of agriculture into Central and Northern Europe as there is evidence of a reduction in crop diversity , the herding of mature cattle used for milk and secondary by-products , and selection for lactase persistence in this population. In the higher latitude regions of Northern Europe, the adoption of agriculture was limited by climatic factors, which reduced growing seasons and limited the viability of Southwest Asian crops, delayed the establishment of full agriculture, and led to closer contact and interaction between hunter-gatherers and farmers . The earliest Neolithic in the Baltics at ca. 7400 B.P. was characterized by population continuity from the Mesolithic, continued hunting and gathering, and the introduction of pottery. There appears to have been no significant shift in diet at the time, and broadscale agriculture was not established until ca. 4000 B.P. in the region . The adoption of agriculture in Scandinavia was characterized by genetic discontinuity and long-term persistence of hunting and gathering and distinct genetic lineages of foragers and farmers, with a gradual cultural diffusion and dietary shifts by 4000 B.P. . The process of Neolithization in Britain was similar to other regions of Northern Europe in that the process was delayedrelative to other European regions, but it differed from Scandinavia and the Eastern Baltics as it appears to have been characterized by the replacement of Mesolithic foragers by diffusion of continental farmers . In central and northern Europe, the Neolithic transition is associated with animal herding and milk consumption because crops were precarious . The delayed transition to agriculture across Northern Europe is associated with evidence for a selective sweep for increased lactase persistence genotypes that occurred from ca. 6000–2000 B.P. with evidence for strong selection after 3000 B.P. .There is evidence for widespread use of dairy products from lipid residues in Neolithic pottery throughout Europe and increased dairy production in northern latitudes . The use of pottery often indicates a greater emphasis on delayed return resources that take time to process through activities like fermentation, and the storage and trade of food . The production of secondary milk products such as yogurt or cheese, which could be consumed without the presence of a lactase persistence allele, likely accounts for much of this evidence . The very earliest evidence for the direct consumption of milk , via whey protein in dental calculus, comes from Northern Europe . Selection for increased frequencies of genetic variants that lead to the persistence of lactase production into adulthood in Central and Northern Europe demonstrates the dependence of human populations on direct dairy products such as milk and that Neolithic culture drove human evolution in marginal environments . These shifts within Central Europe are the likely starting point of selection on FADS1 and lactase associated with the demic diffusion of farmers . Recent evidence suggests that selection for LP in Central and Northern Europe may have been in response to famine or pathogen exposure, and the pattern of LP persistence alleles reflected in ancient DNA corresponds with incident solar radiation , patterns which may be explained in relation to the challenges of establishing crop species at higher latitudes or increased prevalence of zoonotic diseases . While no direct associations between LP alleles and phenotypic variation have been found in contemporary UK Bio-bank data, representing populations buffered from severe caloric restriction or high disease prevalence , the relationship between LP and phenotype in the past is unknown. The process of transition toward agricultural life ways differed in other regions. In the Nile Valley, agriculture was introduced as a relatively complete package from the Levant at ca. 7500 B.P. . While there were independent domestication events of species such as pearl and finger millet, sorghum, and African rice within sub-Saharan Africa, none of these species were indigenous to the Nile region. There is evidence for the presence of herd animals on the same timescale , however, there are variable patterns of lactase persistence genotypes in the region today, which have been attributed to past selection and gene flow from Southwest Asia . In China, there is evidence for the in situ domestication of common and fox tail millet between 10,300 and 8700 cal B.P. and the domestication of rice between 6900 and 6600 B.P. in the lower Yangtze River ; however, the dietary shift toward dependence on cereal crops was a gradual process distributed over millennia .