The Miraculous Origin of Brain Intelligence in Land Animals (Like Us)
When aquatic animals first transitioned to land, a virus-like element probably hijacked their neurons.
During the Devonian period, around 360–390 million years ago, sea animals took their first step onto the land, marking the first appearance of semiaquatic creatures called tetrapods.
Tetrapods had limbs with digits instead of fins, allowing them to move in shallow water and on land (Figure 1). They retained both lungs and gills, allowing them to breathe in both water and land. Over the next 60–90 million years, tetrapods evolved into amphibians and amniotes. Amniotes, in turn, diversified into reptiles, mammals, and birds, fully conquering terrestrial habitats over an additional 100–150 million years.
But during that venture onto land, an extraordinary event occurred: a virus-like element hijacked their germline cells. This invasion endowed their neurons with the capability to form synaptic connections vital for learning and memory. It was the beginning of land intelligence.
(Germline cells are the reproductive cells of an organism, such as sperm and eggs, which pass genetic information to the offspring. Germline genes are then present in every cell of the organism, including…
