Figure 7.8: This tortoise is able to reach leaves high in shrubs with its long neck and curved
shell. ( 12 )
Darwin’s Finches
The most extensively studied animals on the Galápagos are the finch species (birds) (Figure
7.9). When Darwin first observed the finches on the islands, he did not even realize they
were all finches. But when he studied them further, he realized they were all the same type
of bird, and that each island had its own distinct species of finch. The birds on different
islands had many similarities, but their beaks differed in size and shape.
Inhisdiary, Darwinpointedouthoweachanimaliswell-suitedforitsparticularenvironment.
The shape of the finch’s beaks on each island were well-matched with the seeds available
on their particular island, but not the seeds on other islands. A larger and stronger beak
was needed to break open large seeds and a small beak was needed to feed on some of the
smallest seeds.
Darwin also noticed how different species were distributed around the world. The finch,
tortoise and other species found on the Galápagos Islands were similar to species on South
America, the nearest continent. Yet they also differed. Likewise, species he saw on islands
nearAfrica were similar to, but different from speciesonAfrica.