What are the effects of geographic isolation on the evolution process?

what happens to a species becomes isolated from another?What are the effects of geographic isolation on the evolution process?
A good example, is the isolated continent of Australia...





The Platypus, which has fur, nipples and breastfeeds its young like a mammal, also lays eggs, and has webbed-feet %26amp; a duck's bill like a bird, it lives in %26amp; out of the water, like an amphibian, and finally, the males have a venomous stinger in its hind-quarters, like a reptile!What are the effects of geographic isolation on the evolution process?
Isolation in one form or another is one of the driving forces of natural selection. Most species that become separated into isolated populations find an ecological niche by which the process of mutation and adaptation effects phenotypic traits. Different geographic locations provide different carrying capacities, survival conditions, and challenges. Over time, these isolated populations would likely encounter differing and successful mutations. Several classic examples of isolation's effects on evolution include island dwarfism, biodiversity on Madagascar, and the effects of human interaction and artificial selection on Canis familiaris.
Research the Galapagos Islands. Many species evolved there in isolation from the rest of the world. A species will evolve by adapting to it's environment and all contained within it, isolated or otherwise.
When populations of the same species are isolated, they continue to evolve. They eventually become genetically incompatible and then they are new species by even the most strict definition of species.