Worm
While the term ‘worm’ can refer to any number of different animals, many of which have no relation to each other, here we will focus on the common earthworm. Though originally native to mainland Europe, the common earthworm is one of the most invasive species in the world and can be found in great numbers in North America, Australia, New Zealand, Iceland, South Africa, and Asia. While it is not the most numerous species of worm, it is often the most commonly seen due to their habit of coming to the surface after a rain or at night. They are also often the species used in biology classes for dissection.