Charles Darwin's experiences in the Galápagos Islands in 1835 helped to
guide his thoughts toward a revolutionary theory: that species were not
fixed but diversified from their ancestors over many generations, and
that the driving mechanism of evolutionary change was natural selection.
In this concise, accessible book, Peter and Rosemary Grant explain what
we have learned about the origin and evolution of new species through
the study of the finches made famous by that great scientist: Darwin's
finches.
Drawing upon their unique observations of finch evolution over a
thirty-four-year period, the Grants trace the evolutionary history of
fourteen different species from a shared ancestor three million years
ago. They show how repeated cycles of speciation involved adaptive
change through natural selection on beak size and shape, and divergence
in songs. They explain other factors that drive finch evolution,
including geographical isolation, which has kept the Galápagos
relatively free of competitors and predators; climate change and an
increase in the number of islands over the last three million years,
which enhanced opportunities for speciation; and flexibility in the
early learning of feeding skills, which helped species to exploit new
food resources. Throughout, the Grants show how the laboratory tools of
developmental biology and molecular genetics can be combined with
observations and experiments on birds in the field to gain deeper
insights into why the world is so biologically rich and diverse.
Written by two preeminent evolutionary biologists, How and Why Species
Multiply helps to answer fundamental questions about evolution--in the
Galápagos and throughout the world.
