Throughout this blog, I shall often look into the past to help explain things going on in the present, and this article is intended as an introduction to this reasoning as well as some important facts that will make my future articles more comprehendible. If you are an ecologist, like myself, you might wonder someday why anybody bothers to study nature, as it is so unpredictable. I recall during my undergraduate degree, having spent the first two years studying theoretical ecology, being told in my final year, “Just take it all with a pinch of salt”. However, although this may ring some truth, I think the problem here is misinterpretation. Every single organism on this earth is the product of years of evolution. It wouldn’t exist unless it could do so in it’s natural environment. These organisms do not have a purpose they are simply a consequence of the process of natural selection. Because of this, quite fascinatingly, but nonetheless ‘blindly’, organisms have become adapted to their environments. It is the selection pressures in an organism’s environment that drive natural selection and it is these pressures that ecologists are often trying to understand.
What I am trying to say is there is always a reason why things are the way they are. To explain why a giraffe has such a long neck is a question into its ecology or what its purpose is in its daily life. A single giraffe in present time however, is just one of many giraffes that have lived in the past. Its long neck certainly did not crop up during the lifetime of a single giraffe in the present-that would go against everything we epitomize a giraffe to be. The giraffe’s neck is the product of years of evolution with its natural environment, as species are products of their environment. Therefore to explain why a giraffe has a long neck, we must look at the selection pressures that acted on it during its evolution – we must look to the past. I think the problem with studying the ecology of a species is actually the misinterpretation of findings. For example, a study might conclude that giraffes prefer to eat the leaves of Acacia trees. However this does not mean that all giraffes only eat Acacia trees, and that they won’t eat other trees if they need to (I might just point out here that some humans have been known to become cannibalistic in survival situations). It just means that the majority of giraffes eat these leaves because it has benefited them in the past. We must remember although we define groups of organisms as different ‘species’, every organism is essentially its own species; the only thing that binds them together is their interdependency to reproduce. We must also remember that species are always evolving and although the past can explain the present, it is the selection pressures of today’s environment that will determine the future ecology of different ‘species’.
To accompany this article, I present here a diagram of the geological timescale courtesy of the U.S. Geological Survey, which will be useful when referred to in the future. For now all I will explain is that this scale begins at 4.5 billion years ago at the birth of our planet and ends in the present. The past 4.5 billion years of Earth’s history is broken down into periods of time that relate to significant changes in the Earth’s geology.