Life on Earth fell into perhaps the greatest symbiosis ever found between two competing but complementary systems of life, one that lasts to this day. One category of life was photosynthetic converting water and carbon dioxide into sugar and oxygen. The other respiratory, converting sugar and oxygen back into carbon dioxide.
Fungi chose the strategy of waiting and animals chose the strategy of killing.
It is remarkable how little diversity there is in the animal kingdom. Almost all animals on Earth have the same body plan. A front with a mouth, a brain, and the main sensory organs and a back where waste comes out.
Radially symmetrical body plans work fine with the coral strategy of waiting for food. But they work horribly for the hunting strategy of navigating towards food.
The brain’s first purpose was steering with 2 simple rules:
Neuromodulators like dopamine and serotonin evolved long before humans appeared; they began their connection to affect as far back as the first bilaterians.
As far back as the first brains six hundred million years ago, the system for binge eating after a stressful experience was already put in place.
Primates, dogs, cats, crows, parrots, octopi, and many other animals don’t have human-like languages, yet exhibit intelligent behavior beyond that of our best AI systems. What they do have is an ability to learn powerful “world models” that allow them to predict the consequences of their actions and to search for and plan actions to achieve a goal.
Fruit-based diets come with several surprising cognitive challenges. There is only a small window of time when fruit is ripe and has not yet fallen to the forest floor. Sometimes less than 72 hours for 3 weeks per year.
Altogether this meant the primates needed to keep track of all the fruit in a large area of forest and on any given day know which fruit was likely to be ripe; and of the fruit that was ripe, which was likely to be most popular and hence disappear first.
Both carnivore and a non-fruit eating herbivore can survive by hunting or grazing only when they are hungry. But a frugivore must plan it’s trips in advance before it is hungry.