By Sharon Go
Text-only version

Some people think that evolution is something relatively easy to define. But in reality, it's far more complex than one would think... There's a lot of misconceptions about what biological evolution really is. One shouldn't feel too left out when faced with this realisation, because even popular dictionaries give unclear or downright false definitions of evolution.

Ok... So What IS Evolution??

In the global sense, evolution is change. Of course it goes deeper than that. "Biological evolution is a change in the genepool of a species or a population over time" (Chris Colby). It's a process that results into changes that are passed on from generation to generation. A genepool is the set of all genes in a species. A gene is a hereditary unit, meaning it carries information from progenitors to their offsprings. Now if there would be any changes in the genepool of a certain species, not an individual, then that is considered to be biological evolution.

Say What?!?

For example, Darwin discovered several varieties of finches (a type of bird) in different islands the Galapagos archipelago. They had morphological differences that were suited to the island and area they were in. But these changes did not happen overnight. It took hundreds of years for Galapagos finches to change and adapt to their surrounding environment. These changes were passed on from the parent finches to their offspring. The only way such type of changes can be passed on is through genetic information. Thus, a population of finches evolved because their genepool changed.
Just because an individual looks different, it doesn't mean it's necessarily a change in the genepool. You differ morphologically from your parents but that doesn't mean you have evolved! You are part of a population, where everybody has different characteristics. But these characteristics serve as variation, for there cannot be change without variation. Individuals who are adapted to their environment will keep the traits that helped them survive and propagate those traits to their offspring. The characteristics that are not needed in their environment will therefore slowly disappear over time.
Some people think that when a species evolve, they get better. They actually don't really get better, nor do they progress. They just adapt to their surroundings. If their surroundings would change, they would probably be forced to evolve to adapt. This doesn't mean that organisms are slaves to their environment. They too can change their current surroundings like we change ours (buildings, dams, bridges...)

Two Kinds of Evolution

There are actually two kinds of evolution: microevolution and macroevolution. Microevolution is something that happens on a small scale, like Darwin's finches. But Macroevolution is more on the larger scale, like the appearance of an altogether new species. Man's evolution from Australopithecus all the way to Homo sapiens could be an example of macroevolution.

The Importance of Biodiversity

Biodiversity gives rise to possible variations in the genepool. The more possibilities there are, the better the chances of finding the right combination of genes to better adapt to an organism's environment. Variation leads to change. When one population is better suited for the particular environment they are in, they will predominate over another variety of that species thanks to the mechanism of natural selection. Then again, if that other variety were in a different environment, it might predominate the latter. But as long as the variation is there, there will always be a chance for evolution. Nearderthal man grew parallele to Cro-magnon, yet they de-evolve due to the lack of variation. They practised inbreeding throughout the generations and thus remained at a evolutionary standstill. The chances for older, obsolete characteristics to resurface were more pronounced. By introducing new characteristics, we increase chances of change. And that is why variation and biodiversity is so important.

The Beauty of Complexity

Biological evolution not only depends on natural selection. It depends on other factors and mechanisms. But that's the beauty of it, being so unpredictable. It's so complex, yet it's common sense. It's never static, always dynamic. It's no longer a theory that can't be proven. It's not something that is easily defined, much less, grasped. We have a long way to go to fully understand evolution. But it's truly the "cornerstone of modern biology" (C.Colby)