The Galápagos Islands:
The Galápagos Islands are a small, but unique group of islands in the pacific, approximately 1000km west of South America; the islands were discovered in 1935 by the Spanish. Their volcanic origin should make the islands uninhabitable, but in fact, it’s actually teaming with life on the island. The current between the islands is hot and cold, giving it a good diversity, which means there is a variety in living organisms in that area. Life is everywhere on the islands because the animals have learnt to adapt to the conditions, this means that over time, an animal has change in order to fit in with its environment. A few examples of the animals on the islands are the ...view middle of the document...
The underwater volcano has been active for millions of years and it was an artery near to the centre of the earth. Española Island is the oldest of the Galapagos Islands. The Galapagos plumes have not produced a linear chain of islands similar to the Hawaiian Islands, but rather a loose collection of islands. Some geologists believe that the Galapagos mantle plume could be about 90 million years old.
Natural Selection is the process in nature by which, according to Darwin's theory of evolution, only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations while those less adapted tend to be eliminated.
Natural selection is a big deal when it comes to the islands, and the diverse living conditions causes species to form sub species. One of the species on the islands is the land iguana, which has a sub species called the marine iguana, which is the only sea going lizard. The marine iguana has some amazing and unique adaptations to fit in on the Galapagos Islands, although these iguanas look fierce, they survive exclusively on algae and seaweed. They are adapted to have short, blunt snouts and small, razor-sharp teeth which help them to scrape algae of the rocks. They also are adapted to have laterally flattened tails to help them move like crocodiles in the water, as well have having long, sharp claws to help them cling on to rocks on shore or underwater in heavy currents. Also their cold bloodedness means that they can only stay in the cold sea water for a short amount of time before they seize up, and are unable to move efficiently, because of this they have developed to have the ability of being able to dive up to 9m deep, and once they’re out of the water, they can warm up rapidly due to their dark grey skin colour. Another remarkable adaptation they have is their ability to excrete excess sea salt through special salt glands in their nostrils. Finally, if there is a famine on any of the islands, it has been recorded that the marine iguanas become thinner and shorter and then regrow when the amount of food becomes plentiful again. They do this because the amount of food they take in is linked to their bones, so if there is less food they will need smaller bones to help them survive.
Marine iguanas are remarkably well adapted to their environment, but on a few of the Galapagos Islands, it has been noticed that the minority have been feeding on the terrestrial vegetation. This could be due to selection pressures, which is a factor that affects the reproduction of a population, and since there is a decreasing amount of nutrition on the sea algae, there might be a very dramatic effect that occurs, causing a new species of iguanas to evolve.
Charles Darwin's visit to the Galapagos in 1835 is one of the most famous few weeks in the history of science. Darwin started to develop his theory of evolution by natural selection within two years of his...