ved ▁through ▁natural ▁selection . ▁That ▁reason ▁is ▁typically ▁that ▁it ▁ach ieves ▁some ▁result , ▁such ▁as ▁that ▁ch lor oph yll ▁helps ▁to ▁capture ▁the ▁energy ▁of ▁sun light ▁in ▁photos yn thesis . ▁Hence , ▁the ▁organ ism ▁that ▁contains ▁it ▁is ▁more ▁likely ▁to ▁surv ive ▁and ▁reproduce , ▁in ▁other ▁words ▁the ▁function ▁increases ▁the ▁organ ism ' s ▁fit ness . ▁A ▁characteristic ▁that ▁ass ists ▁in ▁evolution ▁is ▁called ▁an ▁adaptation ; ▁other ▁characteristics ▁may ▁be ▁non - function al ▁sp and rel s , ▁though ▁these ▁in ▁turn ▁may ▁later ▁be ▁co - opt ed ▁by ▁evolution ▁to ▁serve ▁new ▁functions . ▁ ▁In ▁the ▁philosophy ▁of ▁bi ology , ▁talk ▁of ▁function ▁in ev it ably ▁suggests ▁some ▁kind ▁of ▁tele ological ▁purpose , ▁even ▁though ▁natural ▁selection ▁oper ates ▁without ▁any ▁goal ▁for ▁the ▁future . ▁All ▁the ▁same , ▁bi olog ists ▁often ▁use ▁tele ological ▁language ▁as ▁a ▁sh orth and ▁for ▁function . ▁In ▁contemporary ▁philosophy ▁of ▁bi ology , ▁there ▁are ▁three ▁major ▁accounts ▁of ▁function ▁in ▁the ▁bi ological ▁world : ▁theories ▁of ▁caus al ▁role , ▁selected ▁effect , ▁and ▁goal ▁contribution . ▁ ▁In ▁pre - e volution ary ▁bi ology ▁ ▁In ▁phys i ology , ▁a ▁function ▁is ▁an ▁activity ▁or ▁process ▁carried ▁out ▁by ▁a ▁system ▁in ▁an ▁organ ism , ▁such ▁as ▁sens ation ▁or ▁lo com otion ▁in ▁an ▁animal . ▁This ▁concept ▁of ▁function ▁as ▁opposed ▁to ▁form ▁( res