Adapting to the Asphalt Jungle
Throughout the history of human civilization, humans have ventured further and further into the wild, ‘taming’ it to suit our needs. Several species of animals such as dogs and cattle have been domesticated for thousands of years as we have depended on these animals for milk, meat, transport, agriculture, and an array of other resources and services. As we have evolved from a hunter-gatherer species to an agricultural society and then finally to an industrial civilization, this has transformed the ways in which we relate to our environment and the wildlife that lives amongst it. For centuries now, we have organised ourselves around hotbeds of civilization: our cities. These urban centers have grown over years, developing into jungles of concrete buildings and asphalt roads that snake in between them, with pockets of greenery scattered around. In this novel ecosystem, several non-domesticated creatures that make up the urban wildlife have taken to various adaptations that have aided them to survive in landscapes defined by the species self-proclaimed to be at the pinnacle of evolution: Homo Sapiens.
According to Darwin’s theory of evolution, certain genetic mutations that aid a few members of a species to adapt to their environment and better survive, also allow them to better pass on these genes through procreation. This is a phenomenon known as natural selection, and the traits that are said to be naturally selected determine the trajectory of evolution. In the current era known as Holocene, the greatest sweeping ecological changes are a result of the impact of growth and proliferation of human civilizations around the world, which has paved the way for the current global urban realm of the living. During such an era, sometimes termed as Anthropocene due to it being defined by the expansion of human civilization, the influences that spur the forces of evolution are largely manmade. Humans have plowed to create agricultural land, built cities, mined, combusted fossil fuels, created widespread pollution, introduced exotic species into native ecosystems and exploited several of earth’s abiotic as well as biotic “resources”. Evolutionary scientists have observed natural selection taking place at a faster pace in urban ecosystems. In fact, scientists have ascertained that the impact of human activity on modern earth and its ecosystems is of great evolutionary significance to the future of life on our planet.
A variety of animals have changed their behavioural pattern to better adapt to the urban environment, including reptiles such as lizards and snakes, as well as monkeys. The Macaques have for long been accustomed to living in close proximity to humans. The Rock Agamas of Bangalore have learnt to be less fearful of humans and have adapted to better navigate their surroundings.
Several bird species, including European blackbirds, European starlings and house sparrows have evolved traits to better utilize the resources of urban environments. These urban-dwelling avians tend to have proportionally large brains, a wide range of diet and nesting choices, and reduced fear of humans.
Most birds use sounds to communicate with one another, whether to defend their territory, attract mates, or interact with their partners and offspring. In an urban landscape, sounds of traffic, construction and human activity can interfere with these channels of communication, hampering these birds’ chances of survival and procreation. Since city noises are generally disturbing at lower frequencies, some bird species have adapted to communicate using sounds at higher frequencies.
The evolution of the house sparrow has been shaped by the forces of the Anthropocene era. The range of habitat of the House Sparrows has closely flocked to that of human civilization, due to their adaptations of being able to digest starch which allows them to feed on agricultural produce and their lack of aversion and rather affable demeanor towards humans. The image of the House Sparrow foraging for leftovers dropped by humans is a common one emblazoned throughout history and across several cultures. Both these traits have better enabled the House Sparrow to survive in proximity to humans, thus resulting in their evolution from their sparrow ancestors.
With the advent of industrialization, humans began to increasingly impact their environment in newer ways. The Peppered Moth was observed to evolve from a predominantly white coloration, which was previously adapted to avoid being spotted by predatory birds, to a predominantly black coloration which provided them with the ability to camouflage into the urban smog composed of polluted air and against tree bark darkened by soot.
Scientists have observed that White-footed mice in New York parks have adapted in different ways to expand their diet in order to include food with high-fat content, such as the fast food and snacks left behind by human park visitors. Another study has observed that European snails have adapted through a change in their shell color from dark brown to yellow, a transformation scientists attribute to increasing temperatures especially in cities.
The expansion of human civilization has transpired at the cost of several other species. Animals such as monkeys have suffered from a loss of habitat as forests are increasingly cleared. Many have succumbed to hunting activity while others have faced a rather indirect fate due to the far-reaching consequences of human activities, such as climate change and a corresponding increase in temperatures, rampant pollution, and scarcity of water resources. Several ecologists are claiming the current loss of biodiversity as the Sixth Extinction in natural history and the first to be almost single-handedly caused by mankind. The consequences of our way of living are being borne by nature at a rate far too rapid for the forces of evolution to facilitate adaptation. If we do not change our ways soon, wildlife unable to keep up with the changing tides of survival will perish, all for the sake of the so-called progress of civilization.
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