So, I'm drafting out a science fiction being. It's a bipedal, anaerobic, autotrophic sentient being that is almost entirely mechanical and it has no DNA or cellular structure - instead, it's physiology is a maze of gears and metal mechanisms (although they do store information somewhat digitally) almost all the way down to the microscopic level. They're made completely of various metal alloys and they live on a planet made of carbon. Petroleum lakes cover 70 percent of the planet's surface and they use it to maintain smooth joints. The surface of the planet is covered in various metal alloys. The atmosphere is rich in various gasses, some of which are flammable. The beings have only one purpose - to create others of their kind. Because they have no cellular structure - no way of physically reproducing - they opt for a different option, assembling others by hand. It can take hundreds of years but in the end, the gain is greater because the beings have no natural predators. Not only this, but each being adds new function to its creation, thus sustaining a form of artificial evolution, you might say. The main issue I have in designing the species is its metabolism. How do they gain energy? Metal cogs and gears that make up an entire organism would surely require a steady and powerful source of energy. My first thought was that the surface of the beings planet was covered in thick layers of powerful gas (such as nitrogen) that they would absorb to maintain homeostasis. There are two issues that I can think of. First, the beings need an almost constant source of fuel and gas vapors could be sparse in some areas and overly thick in others. I came up with a temporary solution to this – the planet has no wind so gas is evenly distributed throughout its surface. The flip side is that an area wherever a being has been is a “dead zone” because the being has used up some of the gas there and it lacks enough gas to maintain any other life forms. Second, how would the being use the fuel? I originally imagined that it would absorb the gas through porous holes and then turn it into energy from controlled combustion processes (similar to cellular metabolism). There might be problems with this as well. For example, would the organism damage any of its components during the process? If a cellular organism was to kill itself due to an accident, it could easily be replaced. But when a non-cellular organism has thousands of irreplaceable parts, a single accident could prove to be fatal. So, what are your thoughts? Is it an organism that could live with a little faith? I'm open to criticism.