WORD BANK beak size, competition, die, deep beaks, environment, evolution, food, genetic, greater, lesser, medium beaks, natural selection,
overproduce, shallow beaks, survive
L
One trait that demonstrates the genetic
variation of finches of the Galapagos Islands is their
beaksize
This variation leads to some finches being better suited to their
For example, after the drought of 1977, finches with
were best suited to the
in the drier
were best-suited. Scientists know this
environment. In the very wet year of 1983, finches with
frequency of finches with the favorable
because in each sampled finch population there is a
in that the finches that are best-suited to their environment survive
trait. This demonstrates
as more
and reproduce, whereas ill-suited finches do not. Finches, like all organisms,
for limited resources.
individuals are born than the environment can support. This leads to
The Galapagos finch
Individuals with less favorable traits fail to reproduce and do not
or change over time, is a consequence of all these factors.
population demonstrates that
