Heartbeat of a 2-day-old zebrafish
From the spots on a cheetah to the long neck of an ostrich, it takes just one trip to the zoo to realize animals come in different shapes and sizes. Though animals can develop in phenomenally different ways, the genes that encode for development are surprisingly similar. How can similar genes bring about such variety? To answer this, scientists turn to model organisms like zebrafish to understand its development from all aspects: genes, molecules, cells, tissues, environment, etc. This video of a zebrafish heartbeat was taken to understand how a single-celled embryo divides and changes to make cells important for the diversity within and around us.
Image by Fengzhu Xiong, Harvard Medical School.