The new Iris van Herpen exhibition at the Brooklyn Museum may chart two decades of the Dutch designer’s practice—but her biomorphic creations are shaped by forces millions upon millions of years older.  Coral systems, skeletons, living alga, water, the coil of a snake, and the movement of a bird’s wings are just some of the natural phenomena that have fed into van Herpen’s visual language. Her couture pieces borrow the natural world’s rhythms and structures, adapting them into gravity-defying garments. “Nature is the best artist that we have on this planet,” she told me during a preview of the show. “To look at a fossil that’s 80 million years old, if you really try to comprehend that time, you realize how ephemeral we are as human beings,” she added. “That is almost the opposite of fashion that we know today.” Installation view of “Iris van Herpen: Sculpting the Senses” at Brooklyn Museum. Photo: On White Wall.…