What is Appendage?
An '''appendage''' is a part of animals attached the main body. Many [[arthropod]]s have appendages on each, or most, of their [[segment]]s. [[Millipede]]s, for example, have many segments, and almost all carry two legs. [[Insect]]s have exactly six legs, two on each segment of the [[thorax]]. [[Antenna (biology)|Antennae]] (feelers) attached to their heads are another type of appendage. Wings, parts of the tail, legs, some mouthparts, external [[sex organ]]s can all be described as appendages. Appendages may be '''uniramous''', as in insects and [[centipede]]s, where each appendage comprises a single series of segments, or it may be '''biramous''', as in many [[crustacea]]ns, where each appendage branches into two sections. All arthropod appendages are variations of the same basic structure ([[Homology|homologous]]). Which structure is produced is controlled by [[homeobox]] genes. Changes to these genes have allowed scientists to produce animals (such as ''[[Drosophila melanogaster]]'') with modified appendages, such as legs instead of antennae. {{biology-stub}} [[Category:Animal anatomy]] [[Category:Developmental biology]]