In the mid-1800s, the scientific maverick Charles Robert Darwin unearthed and described a fundamental biological principle that would go on to transform our understanding of the origin, evolution, and nature of life. He called that principle Natural Selection.
Darwin informed humanity that the organisms that make up the ecosystem of the Earth take part in a never-ending struggle for existence, in which those organisms that are best suited, trait wise, to the conditions under which they live are at an advantage, in the sense that they are more capable of surviving and reproducing than organisms that are not as well equipped to deal with the challenges and obstacles they face.
The implications of this assertion are that heritable traits that are beneficial under the existing environmental conditions become more common over time, whereas deleterious traits are weeded out, and that life has changed (evolved) over time. There is no governor that oversees everything and decides what is to happen; rather, the changes occur naturally as a result of variation in reproductive success.
A five-step illustrated introduction to natural selection
1. Darwinism in a nutshell
2. The fundamentals of natural selection
3. The intelligibility and logicality of natural selection
In light of the information we have at hand today, it’s quite obvious that Darwin was right. One doesn’t even have to look at any of the countless scientific experiments that have verified his seminal theory of evolution to reach this conclusion; all one has to do is inspect how things work in nature. Given that one is perceptive and possesses basic knowledge about genetics and heritability, one will quickly deduce that organisms take part in a battle for existence, in which the “winners” are those that are best suited to their environment.
This can be inferred from the observations that organisms, including organisms of the same species, vary with respects to their design and behavior, as well as their reproductive success, and that there’s a degree of overlap between the traits of parents and offspring and that this heritability is relevant to the organisms’ reproductive success. Put together, this equals evolution via natural selection.
4, The Darwinian nature of the organismal design
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.
The following quote by evolutionary psychology pioneers Leda Cosmides & John Tooby highlights the importance of natural selection in the context of the evolution of organized biological systems.
… natural selection is the only evolutionary force that is capable of creating complexly organized machines. (1)
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 what we know about the workings of natural selection.
5, The bigger Darwinian picture of life
The theory of natural selection confers humanity with the basic means to understand life: how and why species emerge and go extinct, why organisms instinctually operate the way they do, and why there is such an abundance of varied life in nature. It’s almost impossible to overestimate the value and usefulness of Darwin’s principle theory. Pretty much everything that has to do with life on Earth can be effectively organized and understood via Darwinian thinking. Basically, Darwin’s great insights shed light on all major aspects of life.