Consider the sea urchin. Specifically, the painted urchin: Lytechinus pictus, a prickly Ping-Pong ball from the eastern Pacific Ocean. The species is a smaller and shorter-spined cousin of the purple urchins devouring kelp forests. They produce massive numbers of sperm and eggs that fertilize outside of their bodies, allowing scientists to watch the process of urchin creation up close and at scale. One generation gives rise to the next in four to six months. They share more genetic material with humans than fruit flies do and can’t fly away — in short, an ideal lab animal for the developmental…