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A brief history of understanding biodiversity

Photo: Vignesh Kamath/Research Matters

Imagine a parallel world where you wake up to the morning sunshine and look through the sealed window of your room. No exciting splash of green of trees, no birds soaring in the sky or chirping next to the window, no butterflies fluttering by, not even a housefly annoyingly buzzing around! It’s just humans and only humans all around. A sight out of the window is all about a grey world with soaring buildings, zooming cars and a lacklustre sky. How mundane such a world would be!

Though you may shun thinking about a world without animals and plants, the reality is that we may land there pretty soon! Biological diversity or biodiversity, a term used to describe the variety of living organisms on the planet, from the smallest bacteria to largest honey fungus that can grow to 3kms (larger than blue whales or red sequoias), is rapidly disappearing.

Like most species on this planet, we humans also depend on the rich biodiversity of our Earth for our survival. The air we breathe, the food we eat, the houses we build, the clothes we wear and the medicines we take – all these come from Earth’s rich biological resource – the animals and plants. To appreciate and better understand this biodiversity and to increase its awareness, the United Nations has declared the 22nd of May of every year as the International Day for Biological Diversity. This year’s theme is ‘Biodiversity and Sustainable Tourism’

But how about taking a tour of our understanding of biodiversity in itself? In the long course of history, our attitudes towards biodiversity have been evolving. It wasn’t until the recent centuries that we began to scratch the surface and formally understand the importance of the various living organisms around us, their role in the ecosystem and how they are all connected.

First steps in understanding biodiversity

Our knowledge of biodiversity is as old as humanity. Though we may have never recognized, our ancestors who lived in the wild as hunter-gatherers, had a subtle understanding of ‘biodiversity’ of sorts. Through their continuous interaction with their environment, they recognized what can be eaten, what is poisonous, what animals can be hunted or what animals pose danger.

As we progressed, the knowledge of farming allowed us to modify our surroundings and distance ourselves from the wild, building civilizations. In the process, we played God by controlling biodiversity. Dangerous carnivorous animals were hunted or scared away, while others were domesticated and bred for meat, to work in the farms or as companions. Wild varieties of plants were domesticated by picking those that bore tasty and nutritious seeds and fruits, while the distasteful and poisonous ones were discarded.

The earliest known attempt to document and classify biodiversity finds its place in the ancient Greek civilisation. The Greek philosopher Aristotle, observed the different animals and classified them into different groups based on their morphology, behaviour and physiology. Aristotle’s method of classification stood strong for the next 2000 years. Until the early 17th century, it was believed that all the biodiversity that was seen on the Earth then, had existed forever. In fact, this assumption was reinforced by religious beliefs and the phenomenon of extinction was never thought of.

But nature always gave out some clues, which we noticed but misunderstood. The fossils and bones dug out from the earth were attributed to mythological creatures like dragons and gargoyles. A key discovery in 1676 set out a chain of events that shook the entire fundamental beliefs of the world at that time. Robert Plot, a British naturalist and the first keeper of Ashmolean museum, found a very large bone and documented it as the bone of a ‘giant’. Little did he know that he was documenting the first ever bone of a dinosaur! Over the next 100 years, more such bones were discovered and documented which were similar to each other, but resembled none of the current animals.

So what animals were they? Where did they go away? Curious minds struggling with such questions formed a new branch of science - palaeontology. By the mid 19th century, many had begun to acknowledge that there was indeed life on Earth, in a form totally different from today’s living organisms and that biodiversity could change, evolve and maybe, most importantly, go extinct.

Yet another discovery in the 1670s also set a similar chain of events that further expanded our perception of biodiversity. This time, it was too small for the naked eye! With the help of a simple microscope, that he himself had created, Antonie Philips van Leeuwenhoek discovered and documented the fascinating world of microorganisms. Prior to this study of microorganisms, it was believed that grapes turning into wine and the formation of cheese was the ‘hand of God’ or a miracle.

In the 19th century, Louis Pasture and Robert Koch independently expanded Leeuwenhoek’s work and showed that microorganisms were responsible for curdling of milk and also caused diseases. Their discoveries debunked the theory of ‘spontaneous generation’, which stated that smaller organisms like fleas could spontaneously take birth from inanimate objects like dust. While these scientists identified some microorganisms, today, after decades of research, scientists estimate that there might be 1 trillion species of such invisible microorganisms on the planet!

The origin of species and more

With imperialism spread out, the 19th century saw some heroic voyages around the world by amateur naturalist and naturalist entrepreneurs. During these trips of much fanfare, they collected specimens of animals, plants and other living forms found in these regions. The most famous among these voyages were those of Charles Darwin aboard the HMS Beagle and Alfred Wallace. Being the most well-known naturalists of their time, they explored the then remotest corner of the world including the coastline of South America, the Amazon basin and the Malay Archipelago.

The specimens that were collected during various such voyages, and the documentation of organisms that were witnessed, are the basis of many of the ecological theories in science today. The idea of speciation, evolution through natural selection, concept of warning colouration, the Wallace effect, colonisation of remote islands by plants are some examples that form the basis of our understanding of ecosystems and evolution.

The interconnected biodiversity

While recognizing the different types of animals and plants was a solved problem, a bigger puzzle was understanding how these animals and plants are interconnected in an ecosystem, and are interdependent on each other. It wasn’t until the recent years that we have succeeded in doing so.

The story that unfolded in the Yellow Stone National Park in the United States of America is a testimony to this interconnection. Just after the creation of the national park in 1872, protection was not yet granted to the animals in the area, leading to widespread poaching. Elks were regularly poached and also threatened by brucellosis from cattle in the neighbouring ranches. To protect their cattle, ranchers in the neighbouring areas of the national park hunted wolves. In 1914, to promote the growth of elks in the park, the US government ordered the killing of wolves with the last of the wolves killed in 1926. Soon after wiping off the entire wolf population, the elk numbers rose unprecedentedly without any predator to hunt them and the lush landscape of the park began to deteriorate due to over-grazing.

Recognizing this, the wolves were reintroduced in the park after about 70 years, leading to one of the most surprising discoveries in the study of biology, unforeseen by any naturalist. The reintroduction of the wolves helped control the elk population since they began to hunt elks, resulting in the elks avoiding the area of the park where they could be easily trapped and hunted. This in turn resulted in the regrowth of vegetation in such areas and helped other animals to occupy their ecological niches, from birds to beavers and rats to foxes; all organisms found their place in the park. The reintroduction of wolves had another surprising effect – regulating the waterways of the park. The regrowth of vegetation and the presence of beavers ensured that there was less soil erosion, forming more pools, and thus the rivers rarely changed their course and flowed less meanderingly!

While various studies across the world are helping us better understand of biodiversity and explore this interconnection and interdependence. The modern world brings its own challenges for biodiversity. Climate change, urbanisation, deforestation and poaching are taking us towards a mundane grey world – a sample of which you read in the introduction. Do we really want to get there? On this International Day of Biodiversity, it is probably the right moment to focus our attention on how our actions affect other living beings who we share our planet with. We are all connected to each other and extinction of any one of these beings can affect us in unpredictable ways.  After all, who expected wolves to change the rivers?