Teaching Biology & Evolution Through the Watery Matrix of Life

Water is one of the most common molecules in the universe. Water is polarized, but it has many states besides the normal tetrahedron depicted in standard biology texts. Water is also the most ubiquitous molecule on Earth, the universal solvent. It is the internal and external habitat of cells. Ecologically, water is contiguous with life and the chemistry it nourishes. Water merges with everything from DNA to itself in the vast ocean; it is a constant molecule, and it does not change—or does it? Water, is the planet’s unwavering, flowing, but fixed liquid substrate, and it has an elemental and evolutionary story to tell. Water can independently regulate solute transport, entangling with cell proteins to create the aqueous conditions that support life metabolisms and the evolution of other molecules. Water dynamics are rarely mentioned in standard biology discussions, even though biomolecules are strongly influenced by the hydration shells around them. For water to affiliate with all things living requires specialized entry and exiting of water, achievable by a ubiquitous channel protein called an aquaporin. In this article, we will explore water’s often neglected complex relationship with all things biological from an aquaporin perspective. The aquaporin family of proteins is ancient and spans the tree of life in archaea, bacteria, protozoa, fungi, plants, animals, and viruses. From DNA to osmoregulation, aquaporins literally channel the water molecule through geological time. We will also explore the bigger picture of the aquaporin as a teaching tool for evolution. Through the genomic medicine paradigm, we examine diseases that manifest from defective aquaporins. From a visual and arts perspective, we reframe biological processes in the light of the most abundant but nominally understood molecule on Earth: water.