1. List five observations Darwin made about the Amblyrhynchus lizards.
a. They measure about 2-3 feet long.
b. They are cold-blooded.
c. They feed on crab and sea lion feces.
d. They are the only marine iguanas in the world.
e. Their nostrils are connected to salt glands that allow them to expel excess sea salt.
2. Describe two examples of structural adaptations that Darwin observed.
a. Darwin discovered that finches in the Galapagos have thirteen different kinds of beaks.
b. Darwin observed two kinds of giant tortoises that are distinguished by the shapes of their carapaces (dome-shaped and saddle-shaped).
3. Describe two behavioral adaptations that Darwin observed.
a. The marine iguanas have developed several ways of coping with the cold. At night, they huddle together for warmth.
b. In the face of famine, the marine iguanas have adapted by having the ability to shrink their body size. They are able to grow back to their original size once the food is supply increases.
4. Explain how these observations influenced his theory of evolution?
These observations led Darwin to believe that if a certain trait is more advantageous in a specific environment, then the carriers of that trait are more likely to survive into adulthood and to generate offspring than those who do not have that trait. Eventually, the advantageous traits for a species will proliferate. Darwin later called this as "survival of the fittest".