We used to hear about Darwin's theory of evolution as the explanation of the present bio-diversity and leftover fossils found by the archaeologist. Sure, it’s easy to agree that natural selection plays a major role at making the rest of us walk the earth while the unfit succumbed and later on known as part of our prehistoric ancestors. But then again, why were they so different than the survivors at all? One of the explanations I found on a course about biological evolution was the one about Allopatric Speciation.
As we know, it’s the name for” speciation by geographic isolation” which is what happens when a population of a species got divided by barriers which made them separated by locations, which in turns making both (or more) populations developed their genetic differently later on as seen in their descendants.
How in real life would this be happening? Now surely we can use our human populations on earth as logical reasoning. We can clearly see how people who live on East Asian continent part of the world phenotypically different from the people who live on African continent. Though studies said that we all came from Africa, by the time we discovered the fact, we already looked very different in terms of appearance. Of course scientists stated that individual humans’ genetic differences are so miniscule (around 0.1%) that even when we can see how different our appearances are, we’re still the same species.
Just by the fact that geographical separation can create such difference within a species, it’s no doubt genetic diversity between 2 species populations from the same origin can become distinct cousins in the phylogeny tree. One example of such, is the majestic African Elephant. “The African Elephant has always been regarded as a single species but, because of morphological and DNA differences, some scientists classify them into three subspecies “.
And just how an argument based on Allopatric Speciation would prove that Evolution is right? Well, as it’s just one method of how one species can become different species, just think how it gives such impact on earth’s huge scale within such long period of time? Species populations got separated from one another, and little by little they went different ways, and repeat the process from billions of years ago until today. With addition of fossil findings and lab researches, evolution is a mindset that doesn’t just make sense, but proven to be happening even now.
Sources:
http://evolution.berkeley.edu/evosite/evo101/VC1bAllopatric.shtml
http://en.wikipedia.org/wiki/Allopatric_speciation
http://humanorigins.si.edu/evidence/genetics
http://www.darwinwasright.org/speciation.html
http://news.bbc.co.uk/2/hi/science/nature/2282801.stm
