Life Science

Which Embryo Is Human

The visitor is challenged to select which of the displayed embryos is human. Adult fish, chickens, dogs, and lizards don't look much like humans. So why do these embryos look so much alike? The basic design of all these animals is more similar than you might think. Since all vertebrates (animals with backbones) evolved from a common ancestor, the genetic information that guides their development is nearly the same. That's why scientists can learn about human development by studying other organisms—including zebrafish.