The unique life on islands

Maybe you have heard about the rich fauna that lives on islands. Many of them is endemic, that means they live only at one place. It's quite fascinating that there can be like this and we will here see what make it like this and explain the nature of islands.

Why endemic?
So why are so many plants and animals unique at a particular island? It have to do with some of the characteristics that islands have. The most important is that they are not connected to the mainland. There is water in the way otherwise it is not an island we are talking about. This make it hard for animals and plants to get away and to the island. A island that is easy to get to will not result in new species. It is when the species are isolated they will change to be it's own. They adapt to the life on the island witch is often different than on the mainland. The climate is different. Of course it take a long time for new species to evolve. The food on not so big islands are often limited. This make small animals a bigger chance to survive. If we look at the species that lives only on islands and compare them to their relatives on the mainland those on the island is often smaller because they have adapt to the limited amount of food.

How life move
Plants is often very durable and can float a long way. Seed can fly in the wind and so on. That makes the plants not easy to isolate from the mainland. There is some exceptions. Orchids is one. They grow slow and are often sensitive. That's why there is so many orchid species. Some animals swim better than other. Sea living animals like turtles can often spread among islands. What people not think of is the fishes and other animals like frogs that live in fresh water. They can't swim away from the island if the water around the island are salt water. Insects can be in many ways. Some can fly and other can't this will of course affect if they will be staying on the island and maybe become unique species. Birds can fly from island to island but they are actually very good to become unique. If they found a new island they will adapt relative fast.

Different size of islands
There is many kinds of islands. Small islands will of course not contain as many species as a big one. Very small islands can be so small that they not have enough food to feed the animals that lives there. If the island is near the mainland the animals maybe can go over to feed themselves there otherwise it can be empty on big animals. Only insects and that kind can live there. Bigger islands like Madagascar do not have the same food problem. It's more like the mainland but it's still isolated from the mainland so many species are endemic.

Different history of islands
Islands can be created in two main ways. One is that the large landmasses are moving. Then a part of the mainland can move out in the sea and become a island. That is what have happen to Madagascar. These islands will keep there plants and animals. The move goes very slowly so the animals can slowly adapt to the new situation. The other way new islands can be created is by volcanic activities. The Galápagos Islands have been created like this. These islands will have no plants and animals from start. Everything have to come. Plants can float and seed can blow in the wind to the island. Animals have to come there from somewhere but it is hard for many animals to reach the island. Birds is one of those animals that have a chance to reach the island. Volcanic islands will have another kind of fauna than the other kind I described.