The researchers found changes in bill size in birds living in different environments on the Galapagos Islands.
Research fellow, University of Massachusetts (USA) Luis de Leon argues that the power of the bird human food affect natural selection that promotes the formation of new species in the wild. This is the conclusion scientist came after studying finches on the Galapagos island of Santa Cruz.
Galapagos finches are famous for that inspired Charles Darwin on his work on evolution. Their common ancestor arrived on the Galapagos about two million years ago, and since then the finches Darwin has become more than a dozen recognized species differing in body size, beak shape and behavior.
De Leon and his colleagues found isolated in natural conditions on the island of Santa Cruz, two kinds of finches with different size beaks. When they performed the same measurement in the next, populated by people of the district, the differences between the sizes of the beak types were absent. Comparing these results with data collected by other researchers in the 1970s, scientists discovered that changes have occurred over the last 40-50 years. They suggested that this may be related to urbanization and increasing population in the region — in particular, to the emergence of new food products in humans.
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Using the trays for eggs filled with natural seeds and unclean food products, corn and rice, the researchers found that the finches do eat human food, identifying their preferences by weighing food before and after food birds.
Finches living in urban areas, almost exclusively eat human food, preferring it to its natural diet. When the experiment was repeated in isolation from the people the place the finches ignored the trays. This indicates that ongoing urbanization in the Galapagos destroys ecological differences.
“The finches vary their diet of human junk food. We know that a variety of species of birds depend on the diet. All three or four species of ground finches in urban areas on the island of Santa Cruz seem to agree on one and the same love for fast food. If so, selective pressures, which naturally kept them from each other may be weakened, which in turn can lead to the collapse of the adaptive radiation of finches,” explains De Leon.
The researchers also found a strong attraction to human food in birds at EG Beach is located 12 kilometers from the town of Puerto Ayora, a small uninhabited area that is popular with tourists. This suggests that the behavior of the person and not the population density in the region can be considered a major factor in the dietary preferences of birds, extending the effects of urbanization.
Now that researchers know that the finches vary their diet at harmful human food, they want to examine the effects of the actual evolution of species on this island. Group of the scientists will return to the Galapagos Islands in January and will be doing genetic analysis, examining the question of possible increased gene flow among four species of ground Finch. Now, when birds consume the same food, the researchers want to know, do they continue to breed.
As reported by “Around the world. Ukraine”, genetics proved that among the people continues to act natural selection.