Of all the millions of species of animals and plants that live on our planet, which could be considered the most successful? Is it the ant, in which supercolonies exist with over 300 million individuals. Maybe the beetle - without doubt the most numerous species on the planet. Or perhaps it is ocean plankton, without which the life-giving oxygen on which we survive would not be the same. We name the top ten contenders for the most succesful life-form on Earth.