Editing Cephalization (section)

{{Short description|Evolutionary trend}}
{{good article}}
[[File:Lobster, National Lobster Hatchery 2.jpg|thumb|upright=1.5|A [[lobster]] is heavily cephalized, with [[arthropod eye|eyes]], [[Antenna (biology)|antennae]], multiple [[Arthropod mouthparts|mouthparts]], and the [[arthropod brain|brain]] (inside the armoured [[exoskeleton]]), all concentrated at the animal's head end.]]

'''Cephalization''' is an [[evolution]]ary trend in [[animal]]s that, over a sufficient number of generations, concentrates the [[special sense]] [[organ (biology)|organ]]s and [[nerve]] [[ganglia]] towards the front of the body where the [[mouth]] is located, often producing an enlarged [[head]]. This is associated with the animal's [[animal locomotion|movement direction]] and [[bilateral symmetry (biology)|bilateral symmetry]]. Cephalization of the [[nervous system]] has led to the formation of a [[brain]] with varying degrees of functional [[centralization]] in three [[phylum|phyla]] of [[bilaterian]] animals, namely the [[arthropod]]s, [[cephalopod]] [[mollusc]]s, and [[vertebrate]]s. [[Hox gene]]s organise aspects of cephalization in the bilaterians.