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America, are a hotspot of biodiversity. When Charles Darwin explored the Galápagos Islands, he found evidence for his theory of evo-
                  lution all around him. Over millions of years, many new species have evolved on the islands, each with unique adaptations that allow
                  them to live and reproduce.







 Natural Disruptions  Succession
 The Islands originated from volcanoes.   Bare rock is succeeded by pioneer species such as lichen, lava cactus,
 Natural disruptions such as volcanic   and carpetweed. Over hundreds or thousands of years, these plants
 activity and weather pattern changes have   die and create soil conditions in which small herbaceous plants such
 affected ecosystems on the Galápagos.  as common sow thistle and grasses such as Mexican lovegrass can
 grow. Eventually these are succeeded by shrubs and small trees such   Woodpecker
                                                        Woodpecker
 as leatherleaf and manchineel. Finally, in higher, humid zones a climax    nch
 forest can consist of a combination of plants including the giant daisy
 trees, which are endemic to the Galápagos.  Invasive Species
                      Some species brought to the
                      islands by humans have
                      become invasive and threaten
                      native plants and animals.                                                                           Vegetarian
                      Among these species are
                                                                                                                              nch
                      goats and blackberries.                                                                                 nch


                                                Common
                                                  cactus
                                                   nch

 Volcanic  Lichens  Small  Shrubs and  Daisy tree
 rock  herbaceous  small trees  forest
 plants











 Blue-footed  Flightless
 booby  Sea lion  coromant






 Adaptations
 Over time, organisms evolve adaptations
 that help them survive and reproduce in a
 speci c environment. For example, the                                                              Large ground
 marine iguana, the only sea-going lizard                                                                nch
 in the world, has adaptations that allow it   Marine iguana
 to dive into the ocean for algae and
 seaweed and to expel excess salt.
 The  ightless cormorant evolved with
 reduced wings and adaptations that allow
 it to dive to the ocean  oor to hunt for  sh.

                                                                                             Evolution
                                     Galápagos                                               Genetic variation is at the heart of biodiversity
                                                                                             and makes evolution possible. The birds known
                                     penguins                                                as “Darwin’s  nches” are all descendants of
                                                                                             one original  nch. Over many years  nches
 Island Biogeography                                                                         evolved adaptations to  ll different ecological
 Over 600 km from the mainland in South America, the                                         niches on the islands. For example, the large
 Galápagos Islands were initially populated by plants and                                    ground  nch has a bill adapted for picking and
 animals that could reach them by  oating, swimming,                                         crushing seeds. In contrast, the woodpecker
  ying, being blown, or carried. Some initial colonizers                                      nch has a sharp bill adapted for extracting
 evolved over time to take advantage of available                                            and eating insects. The vegetarian  nch has
 resources, making the islands rich in biodiversity with                                     evolved adaptations to pull buds off trees.
 many species found nowhere else on Earth.                                                   Darwin’s  nches continue to evolve today.
                                                   Uncorrected proofs have been used in this sample.
                                                   Copyright © Bedford, Freeman & Worth Publishers.
                                        Distributed by Bedford, Freeman & Worth Publishers. Not for redistribution.

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