Evolution, simply put, is the change in the physical and/or anatomical structure of a species due to external environmental factors. Every organism has evolved since the beginning of time. Along with natural terrestrial changes like the Ice Age, volcanic eruptions, droughts and floods which took place over the course of 4 billion years, species have evolved and have adapted accordingly, to ensure life on Earth. From prehistoric creatures like trilobites, toothed fishes and dinosaurs, to the five-kingdom classification which encompasses every organism present today, the Earth has indeed seen an extensive history in terms of biota.
Coming back to present-day Earth, it is undoubtedly not dinosaurs who rule the planet. From discovering fire to making robots, man has indeed made great progress. In this process, however, humans have also made use of other organisms for their development. Using bacteria for tests against antibiotics, using plants for medicine, animals for drug testing are some of the methods humans have utilised other living beings. How has this affected their survival? And how do these organisms adapt themselves accordingly?
Due to their close relationship with man, these organisms have had to adapt themselves in ways to benefit their own survival. This is termed as ‘anthropogenic evolution’. Animals, plants, fungi and even the tiniest bacteria have thus evolved mechanisms to help them survive the greatest geophysical force of Earth: humans. An extreme case of co-evolution. Here are some examples of evolution in species induced by anthropogenic activities:
Industrial Activities
This is regarded as the most common example of evolution initiated by anthropogenic means. During the industrial revolution, a lot of pollution was created through dust, soot and other particulates. Soot and sulphur dioxide which settled on trees rendered the barks dark-coloured. As a response to this external change, butterflies and moths in the area changed their wing colour to black, helping them camouflage in the background. In this way, through natural selection, the moths were able to escape predators.
Invasive Species have Developed Resistance Pesticides
Products used to get rid of pests and weeds actually induce a sort of resistance among these organisms and thus some species actually become resistant to certain chemicals. Typically, pests develop resistance to these products within 10 years, so much so that eventually, efforts to control their growth become futile. In a similar manner weeds develop resistance within 10-25 years, thus becoming immune to the chemicals which were once considered fatal for their survival. To protect themselves from these chemicals, insects, weeds and other pests develop their genes in such a way that they now are immune to the reaction of these chemicals. In short, they mutate, thus leading to a newly reformed species.
Medicines put evolutionary pressures on bacteria
The progress of human medicine is definitely remarkable. Humans have made use of a wide range of organisms to facilitate discoveries and invent new remedies in human health. In this process, antibiotics have been created which act as bactericides, thus suppressing the disease further. Today, however, due to the massive production and utilisation of a massive number of drugs and antibiotics, their effect seems to have worn out, giving a chance for bacteria to proliferate further.
This is the reason why some vaccines must be taken annually, or even as frequently as twice a year, since bacteria and other viruses become immune to their function. This may turn out to be dangerous for human health and medicine, since at some point of time, there may be a need to replace or reform every single kind of drug to enhance its effectiveness!
From Wolves to Dogs
Dogs are considered as man’s best friend. But were they really so a few thousands of years ago? The dog descends from wolves, a fierce predator known to hunt in packs. Then, how exactly, did dogs evolve from hunter animals to breeds you could carry in your shoulder bag? The simplest answer to this is domestication. Though regarded as a wise step to take, domestication has led to the downfall of many species like cats, dogs, horses and cows.
As their ‘wild’ factor was replaced by the ‘tame’ one, we can say that these species have undergone some sort of atavism i.e., negative evolution. Apart from dogs and cats, even ferocious beasts like tigers are kept on chains and leashes and domesticated for the purpose of touristic pleasure. Furthermore, these places are termed as tiger ‘temples’, sugar-coating the cruelty behind this selfish act. How will this restore balance in ecological communities, if the predator itself becomes a sedated version of its usual self?
Domestication of Wild Species
Besides domestication, the inhuman act of breeding is currently creating a rapid wave of keeping pets. We often see videos surfacing on the Internet showing animals like otters, snakes and even crocodiles being kept as pets, but shouldn’t they be where they belong, in the wild? Furthermore, breeds of dogs and cats are continuously bred as a form of business, making sure to produce exotic breeds in countries whose climate doesn’t even suit the animal. Is this really a positive form of evolution?
Conclusion
Human influences on evolution can thus alter ecological processes at the population, community levels as well as on the ecological function. Apart from direct influence on animals through testing, drugging and other chemical processes, humans also have indirect effects on populations of species through overexploitation of species, habitat destruction, infrastructural development and illegal hunting and trade. This may take a toll on the entire ecosystem in general, if the population of an important element of the ecosystem such as an ecosystem engineer, keystone species or a foundation species is drastically affected.
The decline of species which go through human-induced evolution also affects the decline of human society. Hence, to erase and reform past mistakes, it is time to take up sane measures to end exploitation of biological resources as well as protect biodiversity on Earth.
Efforts such as production of non-Bt crops, size limits and interdictions in the fisheries sector, genetic engineering of mosquitoes which won’t be potential vectors to diseases like malaria, drug discoveries and inventions to reduce resistance evolution in pathogens are some of the ways humans have already started protecting biodiversity, human health, agriculture, and natural resources, all the while not hindering anthropogenic progress and development.
Written by: Shreya Patankar
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