Returning to work or school after spending time with family over the summer may leave us wondering how on earth we are related to some of them. In evolutionary terms, however, we all share ancestors if we go far enough back in time, and many features in our bodies stretch back thousands or even millions of years. Bipedalism, skulls with a single window, pentadactyl limbs, teeth, and spinal cords are all homologous features shared with our shared common ancestors from over 300 million years ago. The act of walking around on two legs enabled rapid increases in brain size, while our teeth, fingers and toes, and spines all evolved over many millions of years. We may be different, but we are more alike than we are unalike.