Due to the fact that the Galapagos Islands were never part of the mainland and arose from the bowels of the earth, their flora and fauna are unique. Most of the representatives are endemic and are not found anywhere else on Earth. These include different types of Galapagos finches. They were first described by Charles Darwin, who discovered their significance in the theory of evolution.
Origin of the species
An endemic group of small birds, some scientists attribute to the family of oatmeal, others - to the tanager. The second name - Darwin - they received thanks to their discoverer. A young and ambitious scientist was struck by the nature of the islands. He suggested that absolutely all finches in the Galapagos Islands have one common ancestor who came here more than 2 million years ago from the nearest mainland, that is, most likely from South America.
All birds are small, body length averages 10-20 cm. The main difference that prompted C. Darwin to think about speciation is the shape and size of the feathered beak. They vary greatly, and this allows each species to occupy its own separate ecological niche. In addition, there are differences in the color of plumage (black and brown are predominant) and vocalization. Watching the birds, the scientist suggested that initially only one type of finch came to the island. It was he who gradually settled on the islands of the archipelago, adapting to various environmental conditions. However, not all Galapagos finches turned out to be ready for life in harsh conditions. Beaks - this is what became the main criterion for natural selection. In the struggle for survival, the advantage was in those species in which they were suitable for local food. Some individuals received a variety of seeds, while others received insects. As a result, the original (ancestral) species was split into several others, and each of them specializes in a specific food supply.
As a result of his research and discoveries, the small Galapagos reel entered the world history of biology, and the mysterious and distant islands became an open-air laboratory, which is ideal for observing the results of evolutionary processes.
Modern look
Inspiring C. Darwin to create a theory of evolution finches actively helped modern science to confirm it. At least that's what Prince Grant scientist Peter Grant and his colleagues are talking about.
By their studies, they confirm that the reason for the appearance of different types of Galapagos finches lies in the food supply and the struggle for it between different populations. In their work, they say that in a fairly short period of time such changes occurred with one of the bird species. The size of the reel's beak has changed as a result of the fact that competitors arrived on the island, and there was a limited amount of food. It took 22 years, which for evolutionary processes is almost equivalent to instants. In finches, the beak has decreased in size, and they got the opportunity to get away from competition by switching to other foods.
The results of over 33 years of work have been published in the journal Science. They confirm the important role of competition in the formation of new species.
A large number of finch nests on the islands, and they are all endemic, but most often there are three main species from the group of earthen. Let us dwell on them in more detail.
Large cactus reel
A small songbird (photo above) lives on the four islands of the archipelago and, as the name suggests, its life is closely connected with cacti. This Galapagos reel is used not only as a shelter, but also as food (flowers and fruits). The beak is oblong, strong, it is best suited for insects and seeds. The color is black, with gray spots in females.
Middle earthen reel
This is one of the types of song finches discovered by C. Darwin in the Galapagos Islands. The structure of the beak is strong, powerful, adapted for clicking seeds of small sizes. The basis of the diet is also insects (in particular, it collects parasites from the skin of Konolof and in turtles), as well as berries. According to recent studies, this particular species can serve as a worthy example of early sympatric speciation. There are two populations (morphs) that differ slightly in the structure of the beak. However, this led to a difference in singing. As a result, individuals of both populations live on the same territory, but they cross mainly only within the morph.
Sharp-billed earthen reel
The amazing Galapagos finch is known primarily for one of the subspecies - septentrionalis. His diet consists mainly of the blood of other animals living on the island, in particular gannets. With a sharp and thin beak, they literally nip off the skin until it begins to bleed. In such an unusual way, they compensate for the body's need for fluid, whose reserves on the islands are extremely small. Presumably, this behavior developed as a result of feeding on parasites, which birds pecked from other animals.
The species exhibits sexual dimorphism: males are predominantly black plumage, and females are gray with brown spots.
Wood reels
The genus consists of six species, they are all endemic and live only on the Galapagos Islands. The fauna and flora of this place are extremely vulnerable and easily destroyed when they intervene. Islands that developed in isolation from the whole world need protection and protection. In particular, the mangrove reel is currently threatened with extinction. Small gray birds with olive breasts live on only one island - Isabela, with a population of about 140 individuals.
Of interest is how this Galapagos reel eats. He prefers large insect larvae, which it is sometimes difficult to get out from under the bark of a tree, so he uses a special tool (sticks, twigs, blades of grass) that he cleverly digs inside. Another bird from this genus acts similarly - the woodpecker reel (pictured), who prefers to use cactus spines, among other things.