The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

But the reigning theories suggest that specialization and cooperativity conserve energy and resources while allowing new, synergistic functions to develop. One part of the collective can handle waste disposal, for instance, while another acquires food—and thus the multicellular cluster acquires an evolutionary edge. One prominent hypothesis, bolstered by experiments and mathematical modeling, suggests that multicellularity evolved to support larger sizes and rapid movement, thereby enabling the organism to escape predation (it’s hard to swallow a snowflake-sized body) or to make faster, coordinated movements toward weak gradients of food. Evolution raced toward collective existence because “organisms” could race away from being eaten—or, equally, race toward eating. The answer may be unknowable, or perhaps there are many answers. What we do know is that the evolution of multicellularity was not an accident, but purposeful and directional.