<http://schema.org/description>
"Go back far enough in our history--maybe about 650 million years--and you come to a time when our ancestors were still invertebrates. That is, they had no skulls, teeth, or other bones. They didn&amp;#039;t even have a brain. How invertebrates became vertebrates is a fascinating question, made all the more fascinating because the answer tells&amp;hellip;"^^<http://www.w3.org/2001/XMLSchema#string>
<http://phenomena.nationalgeographic.com/2006/02/22/the-dawn-of-brains-and-bones/>