Explain how the study of bird beaks supports evolutionary theory.
Darwin gave the theory of natural selection. According to him the fit species would survive. In 1973 a project started to study evolution take its course. This study was headed by Peter and Rosemary Grant, who undertook an expedition to the Galapagos Islands to study the beaks of finches, a type of songbird.
They followed 13 generations of the birds and noticed that indeed the shape and texture of the beak was changing with time. The variation began, when the island was going through a severe drought. The birds with the thick beaks were able to break open the big and hard seeds. The finches with the slender beaks could not break open the seed and died of starvation.
It was then seen that when these thick beaked birds reproduced, the offspring had thicker beaks than their parents. Evolution was being seen in action by these researchers. The climate on the island changed gain. This time it was heavy rain. Now, the environment had flipped over to the side of slender beaked finches. Due to heavy rain, the larger seeds were swept away and only small seeds remained.
The birds with the slender beaks could now easily eat the seeds and survived, while the thick beaked finches died. However, by the next generation the beak size was considerably smaller. In 2003-04 due to another drought, beak size changed again. Recently, the compound has been discovered that turn on the genes for the shape of the beak.