Because of symmetry, a structure that 'works' in its own right can be produced in bulk and used as a reliable building block. Symmetry is also a way to trace the development of organic forms from an inorganic world. Evolution then is built upon these structures to produce ever more complex life forms. Any symmetries that led to useful organs or functions were preserved, such as the multiple legs of a centipede or the multiple vertebrae of the human backbone. Virtually all living creatures have visible symmetries of form and function.
Snail shells have spiral symmetry, and delphiniums have five equally spaced petals.
Life is a production line, molded by genetics but driven by dynamics. Mathematics Awareness Week, the last week of April, is a time to remember that we are not just a collection of genes. All multi-celled creatures have a hidden symmetry at the very core of their being.