Skin uses UVB to form previtamin D, which is then converted, through the function of several organs, into D3. This is how animals are able to manufacture their own D3. UV light also effects how things visually appear to lizards.
http://www.uvguide.co.uk/whatreptilesneed.htm
http://www.anapsid.org/jamesball.html
http://www.anapsid.org/holick.html
http://www.anapsid.org/uvtable.html
http://www.anapsid.org/uvbanne.html
http://www.testudo.cc/
http://www.reptileuv.com/
http://www.solarmeter.com/ -> http://www.solarmeter.com/model62.html
http://www.chameleonforums.com/10-0-reptisun-ok-21451/
http://www.chameleonforums.com/chameleons-regulate-uv-exposure-23548/#post208933
http://www.chameleonforums.com/discussion-lights-uvb-15599/
http://www.chameleonforums.com/bad-chameleon-get-close-18629/
http://www.chameleonforums.com/repti-sun-5-0-a-13239/
http://www.uvguide.co.uk/whatreptilesneed.htm
http://www.anapsid.org/jamesball.html
http://www.anapsid.org/holick.html
http://www.anapsid.org/uvtable.html
http://www.anapsid.org/uvbanne.html
http://www.testudo.cc/
http://www.reptileuv.com/
http://www.solarmeter.com/ -> http://www.solarmeter.com/model62.html
http://www.chameleonforums.com/10-0-reptisun-ok-21451/
http://www.chameleonforums.com/chameleons-regulate-uv-exposure-23548/#post208933
http://www.chameleonforums.com/discussion-lights-uvb-15599/
http://www.chameleonforums.com/bad-chameleon-get-close-18629/
http://www.chameleonforums.com/repti-sun-5-0-a-13239/