Evolutionary Proof

Your body is a temple, but it also has a museum of natural history. Look closely and you'll see parts that aren't there because you need them but because your animal ancestors did. No longer serving their previous function but not costly enough to have disappeared, these remnants of our deep history only make sense within the framework of evolution by natural selection. With your arm on a flat surface, push your thumb against your pinky and tip your hand slightly up. If you see a raised band in the middle of the wrist, you've got a vestigial muscle in your forearm. That tendon you see connects to the Palmaris longus, a muscle that around 10-15% of people are missing on one or both of their arms. It doesn't make them any weaker though. There's no difference in grip strength. In fact, it's one of the first tendons that surgeons will take out so they can use it in reconstructive and cosmetic surgeries. You can find the Palmaris longus across mammal species, but it's most developed among those that use their forelimbs to move around. In primates, that means the muscle is longer in lemurs and monkeys and shorter in chimps, gorillas, and other apes that don't do a lot of scrambling through trees. It's not the only leftover muscle that we've got. Look at the three that are attached to our outer ear. We can't get much movement out of these muscles, especially compared to some of our mammal relatives who use them to locate the sources of sounds. Presumably this would have been quite helpful for early nocturnal mammals.

Humans have remnants of an adaptation that allows them to detect the sound of a sudden sound coming from their left ear. This adaptation can be seen with electrodes, and can also be guessed based on the location of the sound. Goose bumps are another example of a futile effort by our body parts. Birds can puffy in cold weather because adrenaline is one of the hormones that help create this response. And in some people, music can cause Goosebumps because it can trigger the fight or flight response. The most adorable vestigial behaviour is where infants up until they're 6 months old have a great grasp on whatever you put in their hand.

Evolution has been surrounded by myths and misconceptions. Although some consider it controversial, most scientists support it. Understanding evolution can be nuanced. One earlier, now discredited, theory by Lamarck suggested organisms develop traits over their lifetimes and pass them on. However, genetic inheritance, not acquired traits, drives evolution. Giraffes' long necks aren't due to stretching; genetic mutations lead to advantageous traits. "Survival of the fittest" is often misunderstood; adaptation to the environment matters more than sheer strength. Evolution hinges on reproduction, not just survival. For instance, the male anglerfish's quick mating reflects this. Organisms not reproducing aren't "useless" evolutionarily, as genes spread within relatives. Evolutionary language like "genes wanting" is metaphorical; genes don't have desires. Evolution is both factul and a therotical, these can widely observable in laboratory and natural populations as they change over time. The fact that we need annual flu vaccines is latest example of Observable evolution. At the same time evolutionary theory explains more than observations, as the succession on the fossil record. Hence, evolution is also the scientific theory that embodies biology. Additionally, facts that are able to construct fairly consistent phylogenetic tree using distinct genetic markers in the genome is well explained by evolutionary theory. Finally, the processes that drive evolution both on long and short time scales, are observable facts. No predetermined plan exists; evolution is blind and incremental, leading to the diversity we see today.