you're aboard the Beagle. You've carefully collected five tortoise
subspecies from five different islands for observation. But a flash
rainstorm has mixed up the field journal pages that show which tortoise
lives on which island.
Consider the evidence and return each tortoise to its home island.
you start on your mission, it’s helpful for you to know that
giant tortoises have three different kinds of upper shells, usually
called carapaces. Darwin was intrigued by these different shaped
shells. But it took many years to determine that the different shaped
shells were adaptations to the particular environments of each island.
tortoises – have longer necks and legs than their
domed buddies, and have a shell shape that lets them extend their
heads up higher. These tortoises live on drier islands with scattered
plant life that's often hard to reach from the ground. Over many
generations the tortoises with “saddleback” shaped shells
were more successful at getting food from higher bushes and trees
than dome-shaped tortoises. The tortoises that ate better were also
better able to survive and reproduce.
tortoises – live on wetter islands with plenty of
vegetation available close to the ground. Domed tortoises have the
advantage of being better protected against attacks from predators
because they can draw their neck and head into their domed shells
and block off their shell entrance with their front legs.
tortoises – tortoises that live on islands with climates
that are in between moist and dry. Intermediate tortoises have shells
that give them more protection than saddlebacks, but less than domed
tortoises. They can reach higher than domed tortoises, but not as
high as saddlebacks.
HOW TO PLAY
Click each of the five tortoises to learn more about it. As you
examine the tortoise, figure out what kind of shell it has: saddleback,
dome, or intermediate.
Then take a look at each of the five islands. When you think you
have a match drag one of the tortoises to one of the islands.