Evolution—The Theory and Its Supporting Evidence - The Changing Earth: Exploring Geology and Evolution - page 470

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Figure 18.1 Darwin's Finches of the Galápagos Islands These birds probably evolved from
accidental immigrants much like the blue-back grassquit fi nch that lives along the west coast
of South America.

Tree dwellers Ground dwellers

Mangrove finch

Large
insectivorous
finch

Large
ground finch

Tool-using finch

Medium
ground finch

Medium
insectivorous
finch

Vegetarian
tree finch

Small
ground finch

Small
insectivorous
finch

Cactus finch

Sharp-beaked
ground finch

Cocos island finch

Berry eater

Large
cactus finch

Seed eaters

Insect eaters

Warbler finch

Cactus eaters

Insect eaters

a Darwin's fi nches arranged to show evolutionary relationships.

Four of the species of Galápagos fi nches. Note the differences in size, color, and beak shape.

b