**Your intelligent geko needs to reproduce**  

Intelligence is obtained in a species with mutations through evolution, not making one single element living longer (some turtles can live up to 200 years, more than any human does actually, and that doesn’t make the turtles more intelligent).  
The process works like this: If your geko is a little more intelligent than the other gekos, and that is an advantage in their current ecosystem, then the intelligent geko will have more chances to reproduce and distribute its “intelligent genoma” to its brood, so the intelligence can evolve IF it is an advantage for the species. But the intelligence of that geko will not raise just by living longer.