Man and his Environment
Ever since the dawn of time, the human race has had a deeply complicated relationship with its environment. Humans have changed the physical, ecological and biological components of the natural world to an astonishing degree. Those environmental changes impact human populations in return, and continue to shift, often in unanticipated ways.
Take the Aral Sea disaster for example. From the 1920’s till the break-up of the Soviet Empire, the Soviets heavily polluted the area in their efforts to turn the region into a vast cotton plantation. Heavy use of pesticides and other chemicals contaminated the sea and ground water. Huge irrigation networks diverted so much of the rivers that nearly all of the water flow to the sea was cut off. All this had an extremely negative impact on the surrounding human population. What was once a vibrant, fish-stocked lake became a massive desert that produced salt and sandstorms that killed plant life and had negative effects on human and animal health for hundreds of miles around. Diseases such as hepatitis due to poor drinking water became rampant and salinization ruined the land, deeply affecting the livelihood of surrounding populations.
Another similar case was observed in 1956, when the first human patient of the Minamata disease was identified. This affliction was a result of industrial poisoning of Minamata Bay by the Chisso Corp., who had long been the port town’s biggest employers. As a result of wastewater pollution by the plastic manufacturer, large amounts of mercury and other heavy metals found their way into the fish and shellfish that comprised a large part of the local diet. Thousands of residents slowly suffered over the decades and died from the disease
As much as the human race tries to modify nature according its needs, the natural world inevitably ends up shaping the evolution of humankind as well. Several interesting studies by scientists from the sea floors around Africa have helped draw a clearer link between climate change and human evolution. Cores drilled out of the sea bottom contain layers of dust blown off the surface soils of Africa. Analyzing these layers of dust back to five million years ago, a critical period in hominid evolution, paleoclimatologists have constructed a picture of changes in climate and vegetation, matching them to major developments in the evolution of humanity’s ancestors as shown by the fossil record. They find that a major cold, dry spell 2.8 million years ago forced woodlands in sub-Saharan Africa to yield to grasslands. Animal species, including pre humans, would have had to undergo major adaptations to accommodate to this shift in their environment. It is known that around this time, the ancient pre human line apparently split into at least two branches. One was the genus Homo, which led in time to modern humans. The other was a kind of ape-human, known as Australopithecus robustus, whose line ultimately became extinct. Even though there may still not be enough evidence to draw a conclusive answer, this study still gives an idea of the definitive impact change in environment has on human evolution.
Perhaps the case of specific varieties of Mediterranean thyme, may be a stronger example. These varieties produce oils with different chemical compositions, and the ones with stronger smelling compounds like phenols are more effective at deterring herbivores. Producing phenols typically comes at a cost, though, as these plants are more sensitive to freezing. But in southern France’s Saint-Martin-de-Londres basin, winters are getting warmer. Since the 1970s, the basin has seen fewer freezing nights during the cold season. Looking at 24 populations across the basin in 1974 versus 2010, one study found an increase in the proportion of plants that produce phenolic compounds. These plants are even popping up in areas where they didn’t grow in the 1970s. Since the plant’s genes determine the chemical composition of its oils, it’s likely that genetic changes are behind wild thyme’s response to warmer winters.
In a nutshell, the interaction between human beings and their environment is a multi-dimensional and complex phenomenon. Mankind is constantly interacting with the environment for its survival and will continue to do so, playing its part in an ever-growing and ever-evolving relationship.
