ABSTRACT
Serious migration to the land could never have happened at all unless the land had begun to offer its own food. Fortunately for the first settlers, the land had been supporting microbial life for over 2 billion years. Eggs have a very low chance of surviving the fossilisation process so it is difficult to know when animals that did not lay eggs in water first arrived first arrived. All existing and extinct vertebrates evolved from the jawless fish. This explains why they all share the same basic brain layout, and also possess the same set of basic learning processes. The original vertebrate evolved into all the major classes we know today, with the jawless lamprey fish thought to be its closest living relative. The "tripartite" ground plan of the brain has been preserved, with modifications reflecting the demands of different evolutionary "niches".
