I was looking for interesting accounts on Tumblr that I can follow when I stumbled upon: itsokaytobesmart.com. I have always been fascinated with the origins of human life, the universe, things like that. So when I discovered this site, I find myself grinning because it contains all sorts of science-y stuff. This website was created by a biologist and you can feel his eagerness to share his knowledge about science. He also has a YouTube account with the same name so he can explain matters in depth.
There was one interesting post about why the brain is located in our heads. It was a video clip and I didn't really focus on what the answer was because I was distracted with what he was explaining at the beginning. (And now, I will try my best to reiterate what was explained on the video) He explained first how the brain was formed. And then came a picture of what looks like a worm. I call it a 'simple worm' because it doesn't have any other parts. I mean, there's no heart, no internal organs, it was just a simple organism composed of symmetrical cell structures on both ends. But through evolution, one side of it was being more interactive with the environment; thus, developing more complex cell structures. That other end of the worm was being more developed than the rest of its parts and it's called adaptation. And that's where it all started. Simple organisms, adapting to different kinds of environment, creates different kinds of species, evolving through time. I really can't explain it well enough but this is how I understand it. I was really entertained. First question that came to my mind was, why does it seem like humans have stopped evolving?
And then of course, I googled it. Two answers were offered. The first one, human evolution hasn't stopped. It's just veeery slooow. Human evolution is a process, not an event. And then the second answer was the opposite. He (Sir David Attenborough, a scientist I'm sure) proposed that humans have stopped evolving because we are now very well adapted to our environment. And because we, humans, have put a stop to natural selection (process where organisms interact with the natural environment, resulting to evolution). One very good example where natural selection barely exists now: If it's hot, we can just turn on the AC and when it's cold, there could be heaters available. Because of technology, we are more in control. He also said that, "We are the only species to have put a halt to natural selection, of its own free will, as it were."
Then napaisip nanaman ako, bakit may iisang specie lang ang mga tao? Na-explain na din siguro to dati sa school pero ngayon ko lang naintindihan. Familiar ako sa mga Homo Sapiens at Homo Erectus na sila yung mga sinaunang tao. Pero ngayon ko lang nalaman, na magkaibang human specie pala sila (May isa pa, mga Neanderthals). At ngayon ko lang nalaman, na sa Homo Sapiens tayo nanggaling. Hindi daw naka-survive sa natural selection yung mga H. Erectus at Neanderthals. Tas yung isang specie, kaya daw na-extinct gawa nung sumabog na bulkan 2M years ago. Kaya, H. Sapiens na lang daw ang natira at dun tayo nanggaling. Isang theory kung bakit naka-survive ang mga H. Sapiens, kase dahil sa brains nila. Mas matatalino daw sila kesa sa ibang human specie noon. Kaya yun.