The other phylum that has received particular attention is the arthropods, which includes insects, crustaceans, spiders, and many other less familiar animals. This is an ancient and tremendously diverse group of animals, so any generalizations should be made with caution. Arthropods were among the earliest animals to evolve complex active bodies — and correlatively to evolve brains capable of adaptively controlling complex adaptive bodies (Trestman 2013a), and so if the function of consciousness is to solve problems raised by the control of complex active bodies (cf. Merker 2005), it may have evolved early on in the arthropod lineage, in a common ancestor of all living arthropods. 