What caused humans to become the top species on earth, and why is there such an intellectual gap between humans and all other species?
In: Earth Science
Short answer is that evolution is a crazy, random process caused by random mutations. If that mutation is beneficial, it gets passed down (as that individual is more likely to survive and thrive). Apparently, having a larger brain was more beneficial for our ancestors. This could be because having more tool-making skill increased survival, it helped us socialize and work together, etc.
At some point, we became a dominant species. This would increase selection pressure for intelligence, because now we’re competing with ourselves instead of against the rest of the natural world. If intelligence is what helps me reproduce more often, it makes sense that we would increase in intelligence.
Other animals don’t need larger brains because they haven’t proven to help increase survival rates. There’s actually a lot of downsides to a large brain. One of these is that it takes up a lot of energy: if I’m low on food, having a large brain is actively harmful because it’s burning energy without helping me. Big brains also equal big skulls, making birth much more difficult. For a lot of animals, being born with a fully formed brain is important so that they can start feeding themselves immediately. Humans give birth to offspring with undeveloped brains. This is beneficial in that it allows us to have a larger and more complex brain when we reach maturity, but the downside is that we can’t fend for ourselves right out of the womb.
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