How did evolution turn something with no bones into a creature with vertebrae

darwin's theory of natural selection has shown that variation can be seen among species, and that the ones most adapted to the environment survive causing the species to evolve ("survival of the fittest") and now this is backed up scientifically by the fact that DNA can mutate and create variations during cell division and fertilization... HOWEVER: i have no clue as to how in the world bone tissue can arise from genetic mutations, please help :)

"how did evolution turn something with no bones into a creature with vertebrae?"

Sharks, for example, have no bones but do have vertebrae. The vertebrae developed before bones. Bones have evolved from cartilage. They still develop from cartilage for bony critters during the growth of the embryo. The relevant bits of cartilage ossify.

It's believed that the first step in the evolution of vertebrae was a notochord similar to that found in the motile stage of certain deuterostomes such as tunicates. In the second step, the motile stage became dominate over the sessile stage as is the case in the modern chaetognaths. The next step was primitive cartilaginous fishes such as the placoderms, then sharks and rays, and finally bony fish. Of course, this entire process took place over a period of many tens of millions of years.

A main point of Darwin's theory is not that variation is seen among species--that is too obvious to need mentioning--but rather that gene-based variation exists among individuals of the same species.

http://www.mansfield.ohio-state.edu/~sab…

" HOWEVER: i have no clue as to how in the world bone tissue can arise from genetic mutations"

Many invertebrates have exoskeletons. Mollusks often have calcium carbonate based exoskeletons. Put the cells that excrete the exoskeleton on the inside instead of the outside and you are on your way to bones.