It depends what kind of lamp it is. It's either to provide heat or light - or both !
decorative
It is just for decoration
we still use the Widow's Lamp to comemorate the momory of the race accoring
Well it depends on the reptile but generally you can get a glass tank, get synthetic grass, a food dish, a heat lamp (50-100watt) and some kind of rocks or branches or what ever kind of habitat best suits your reptile. Ex. for a tropical reptile heat lamp, vines, high humidity, smooth wood to climb and a big water dish. Or for a desert reptile fine sand, a small water dish, some kind of hide hole or box and a nice hot heat lamp. But before you do consult your local pet shop and they will point you in the right direction. And if it is a spare of the moment thing a plastic tub or bucket with a lid or something of the like should suffice until proper arrangements can be made for the reptile.
It is just for decoration
what the function of lamp holder
A backup lamp on a vehicle is there to see what is behind it. Another type would be a extra lamp ready to use if the main lamp fails.
It is just for decoration
To control the burn rate
to show God was the Eternal light.
That would depend on what type of turtle or reptile you are referring to. All animals do need a break from the UV's at some point.
To improve management decision-making.