Completely unrelated species on each of the islands.
Species exactly like those found in South America.
Somewhat similar species, with traits that suited their particular environments.
Species completely unrelated to those found in South America.
Have the ability to interbreed.
Acquired traits through use and disuse.
All eat the same type of food.
Descended from a common ancestor.
How species become extinct.
How inherited traits are passed from parent to offspring.
How species change over time.
How evolution takes place in the natural world.
Similarities of the birds’ embryos.
Birds’ different-shaped beaks.
Length of the birds’ necks.
Number of eggs in each bird’s nest.