This website is really cool! I just helped a student answer a regents question today about population growth, and this site does a great job explaining it. The section where you put your age and it tells you how many people were around when you were born, in comparison to what it is now is a good way to make the idea of population growth relevant.
This website would be a great introduction to thinking about evolution or adaptation? How does an octopus' eye help it see under water? How do an owl's eyes help it see at night? In terms of evolution, how have eyes changed over time? What differences do we see? Questions like these could be explored.