Part 5 in a series. Click here for part 4: why natural selection is not random
Things have felt a bit different lately. Perhaps it’s the weather. Maybe it’s the new baseball season. No? Oh, I’ve got it—it’s been too long since we had a Misconceptions About Evolution!
My freshman year of college I had a floormate named Steve. Steve’s man goal in life was to get better—no matter the subject, his aim was to come out more accomplished than he came in. Everything Steve did had this goal in mind—he studied, exercised, and ate with more fervor than the competition, and sure enough he became slightly better. Well done, Steve.
Many see evolution in the same light. Species are constantly getting better, improving themselves to become evolutionarily superior…except not quite. Much like Steve’s devotion to self-improvement, there is much more to this than meets the eye.
Why species are not “getting better”
Let’s recall the basic ideas behind evolution. Over time a species’ genetic makeup changes. These alterations stem from mutations, outside pressures, and statistical phenomena. While many of these changes have little effect, some can increase an individual’s chances of survival and reproduction. Let’s use the example of a fish with improved eyesight. Our seafaring friend will be able to better identify food and predators, which will in turn increase his odds of survival.
As our fish reproduces, some of his offspring carry his new trait. These little fish again survive more often than the others, and in time a sizable portion of the fish population will have better eyesight. This is the beauty of natural selection. So far, it seems the Steve analogy applies—our fish friends are getting better.
Now imagine the lake experiences an algae outbreak. Microorganisms cloud the surface, cloaking the water in darkness. Our fishes’ eyesight, previously an optimal trait, can hardly make out anything at all. This is a bad day to be a fish. Any that relied on eyesight will either starve or find themselves in the belly of a predator.
So what happened? Even though the fish’s vision allowed it to thrive in direct sunlight, it became useless in the dark. An ability advantageous in one situation proved ineffective in another. This is the key to understanding natural selection—species adapt to their environments. This includes everything from amount of sunlight to terrain and predators. Unfortunately for Steve, “getting better” has no meaning in natural selection.
As for our fish friends, their future is uncertain. Maybe individuals with better hearing will find higher rates of survival in the new world. Perhaps the population will die out. It all depends on the fishes’ surroundings and which traits ensure higher chances of survival.
So there’s a bit of Misconceptions About Evolution to brighten your day. Is this surprising? Confusing? Remarkably good looking? Let me know in the comments below. As always—you know the drill, so please share, like, comment, and subscribe if you like the post! Thanks for reading! Don’t forget to subscribe for new content every Wednesday. IT’S FREE!
Comment question of the week
Are human beings currently “getting better?” Why or why not?
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