bio- :word-forming element, from Greek bio-,

 combining form of bios "one's life, course or way of living, lifetime"
 (as opposed to zoe "animal life, organic life"),

 from ProtoIndoEuropean root *gweie- "to live"
or PIE root    *gwiwo- "to live" 
(cf. Sanskrit     jivah "alive, living;"
  Old English      cwic "alive;"
  Latin         vivus "living, alive," vita "life;"
 Middle Persian    zhiwak "alive;"
 Old Church Slavonic  zivo "to live;"
 Lithuanian       gyvas "living, alive;"
 Old Irish        bethu "life,"  bith "age;"
 Welsh          byd "world").

 Equivalent of Latin vita. The correct usage is that in biography, but in modern science it has been extended to mean "organic life."

 * これは バイオロジの bio- であり それは 動物としての生命組織とそのハタラキを――それを意味していた zoe (つまり 動物園の zo- ですね)に代わって――担うようになったとか。