of examining the specimens he had collected and sent back to England, many of which came
from these islands.
Figure 7.5: The Galápagos Islands are a group of 16 volcanic islands 972 km off the west
coast of South America. The islands are famous for their many species found nowhere else.
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Darwin was amazed by the array of life he saw on the Galápagos Islands. He saw animals
unlike anything he had ever seen before. Darwin was struck by how the same kind of animal
differed from one island to another. For example, the iguanas (large lizards) differed between
islands (Figure7.6). The members of one iguana species spent much of their time swimming
and diving underwater for seaweed, while those of another iguana species lived on land and
ate cactus. In England, he was accustomed to watching cormorants fly, so he was surprised
to find flightless cormorants on the islands alongside flying cormorants.
Giant Tortoises
Giant tortoises (Figure7.7), large enough for two men to ride on, plodded across the islands
and foraged on super tough leaves. Some of the tortoise species were found on only one
island. Darwinwasfascinatedbythenumberofwaysthatorganismswerewell-suitedtotheir
environments. Even the tortoise shells were specially adapted to the conditions. Tortoises
that ate plants near the ground had rounded shells, while the tortoises that stretched their
necks to reach plants higher in shrubs had shells that bent upwards, allowing them to stretch
their necks upward (Figure7.8).