Life, in all its beauty and complexity, is not arbitrary or designless. Rather, it was molded over billions of years through the process known as evolution via natural selection. This process is not planned, in the sense that there doesn’t appear to be a conscious designer in place that decides exactly what is to happen; rather, the changes that take place occur naturally as a result of variation in reproductive success resulting from genetic/phenotypic variation.
If we go back in time, to the origin of life, and then work our way forwards, overseeing the evolution of life, we’ll discern that the living world has become more complex and “advanced” over time, with new and often larger life forms arising from smaller ones, all of which are bound together by common descent, forming a tree of life that’s breathtaking in its spectacularity. This is part of the beauty of Darwinian selection. Given sufficient time, it can turn something very simple into something very complex.
The realization that all of the life forms that have ever existed on this planet have taken part in this evolutionary peregrination is profound, and can help us make sense of pretty much everything that has to do with life, ranging from why peacocks are equipped with a colorful plumage to why mothers will go to great lengths to protect their children to why we find sex so stimulating and enjoyable. Furthermore, it can help us make sense of why organisms are built the way they are…
It’s not a coincidence that organisms give the impression of having been designed
There’s nothing random about the way organisms are built. Every major attribute of the organismal design serves – or has served – some type of purpose. This is something that can be inferred from Darwinian reasoning (there’s no reason to evolve something that has no function), as well as from examinations of the natural world.
If you stop for a second and think about the way organisms of different kinds are built and spread out in nature, you’re likely to recognize that each distinct life form appears almost perfectly suited to do what it needs to do to survive under the specific conditions that it lives. Take a polar bear for example. It has thick, white skin, which enables it to stay warm in the cold habitat it inhabits and camouflages it, blurring the distinction between bear and snow. It has an impressive set of teeth, including sharp incisors and jagged premolars and molars, and a heavy, muscular build, all of which perfectly suits its carnivorous way of life. Furthermore, if you were to examine the way its internal organs function, you’d find that they all appear to be configured in such a way that their morphology and capabilities precisely meet the demands that are placed on them.
This is not a unique feature of polar bears; it’s seen all over the place in nature. It’s not something we tend to think much about though. We tend to just take it for granted that nature “works” and that organisms are built the way they are. We tend not to dwell so much on the matter of why or how they are built the way they are. That’s somewhat unfortunate, as it may lead us to overlook many important features of life, in particular features that have to do with the connection that exists in nature between the design and the environment of organisms.
From a Darwinian point of view, it’s not surprising that each distinct group of organisms appear biologically suited/adapted for a particular set of circumstances, nor that organisms that are subjected to an environment that doesn’t suit their biology express an unpleasant phenotype. It’s exactly what one would expect, given that natural selection acts over evolutionary time so as to bring about organismal adaptation to ever-changing environmental conditions.
Furthermore, it’s not shocking that life appears to have spread out, exploiting available niches all over the place. It’s not a given that large organisms such as ourselves exist, but it’s not wholly surprising either, seeing as it’s easy to imagine that it would have been beneficial, in the past, when only small life forms (e.g., bacteria) were around, to evolve “into” and adopt new, “higher” positions in nature.
A depiction of the Darwinian nature of the organismal design
So as to illustrate the idea that we’re Darwinian creations, I recently created the infographic below. As you see, the creature that’s featured in the illustration is a lion. It might as well have been a human, tiger, caterpillar, or any other life form though, as we’re all under the jurisdiction of natural selection.