Groups move efficientlyarmy ants
Army ants move efficiently in large numbers by maintaining three lanes of traffic; two outer lanes travel opposite the inner lane and are governed by behavioral differences related to possession of food.
Branches accommodate algaesea slug
The gut of one sea slug accommodates the algae it farms for nutrition by branching into leaf-like tentacles for increased housing space.
Optimizing size aids survivalsessile barnacles
Populations of sessile barnacles optimize space where physical habitat is limited by decreasing the average mass of an individual barnacle as population density increases.