>If all that tissue is not needed, then why did evolution conserve it? It consumes energy, adds size, and increases weight and head size which reduces agility.

>If all that tissue is not needed, then why did evolution conserve it? It consumes energy, adds size, and increases weight and head size which reduces agility. Because evolution is just survival. Fittest doesn't necessarily mean "best", particularly if we're talking about individuals of the species. What genes live on are what worked well enough to be passed on to offspring and didn't happen to get erased from the gene pool.