We often associate brains with humans, but all mammals also possess them. However, not all living beings have a brain, and it's believed that brains only emerged around 500 million years ago - more than 3 billion years after life began on Earth. So, why evolution created the brain?
Before the existence of brains, simple creatures relied on basic mechanisms for survival. For instance, bacteria move towards resources they need, like food, and change direction when resources become scarce. Bacteria don't know their location; they merely move forward, following a straightforward rule for when to change course. So you don’t necessarily need a brain to move, but as life grows more complex, being able to move more smartly becomes important.
Our current best theory is that brains were developed to help creatures better navigate their environments and stay safe from predators. However, it comes with a disadvantage: brains consume a lot of energy - 20% of our energy is consumed by our brains. That’s why a brain is not the best tool for all creatures, with some scientists now believing that some creatures such as sponges, might have had a rudimentary brain millions of years ago but evolved to lose it because the energy consumption wasn't worth the added value.
Human brains have evolved into powerful tools for storytelling and creating narratives. Remarkably, these complex abilities stem from a basic survival skill: attuning to our environment. Though we no longer face the threat of being chased by a lion, the capacity to be present and analyze situations remains a vital function of our brains.
Craving more? Check out the source behind this Brain Snack!
