Photo by Mark Olsen[/caption] The most common shape for typical seed-eating birds is a short, thick, and conical beak. Think of the classic "triangle" shape. This strong, sturdy beak acts like a ...

Under these drastically changing conditions, the struggle to survive favored the larger birds with deep, strong beaks for opening the hard seeds. Smaller finches with less-powerful beaks perished.

How do you know that finches' beak depth is heritable? You can see from Figure 2 that there is a correlation between the parents' and offsprings' beak size. How did the finch population change ...

Caption Darwin noted how different finches from the Galapagos Island developed different kinds of beaks, based on the food that they specialized in eating. Later studies showed how rapid ...

The different finch species on the islands are closely related to each other, but show wide variations in beak and body size and feeding behaviour. In particular, changes to the size and shape of the ...

They consult genetic scripture. Consider, for instance, the famous finches of the Galápagos. Darwin could see that their beaks were variously shaped—some broad and deep, others elongated ...

Darwin's drawings of the different heads and beaks of finches Darwin's observations revealed that the finches had wide variations in their size, beaks and claws depending on which island he was ...