Briefly describe how fossilization might occur for vertebrates.
Fossilization occurs in animals that died and were buried very quickly, perhaps in mud, a body of water, or a sand storm. Over time, more sediment continues to pile on top of the animal. Most of the animal decays but the harder parts remain, such as the bones and teeth. If there is water seepage (and there needs to be for a fossil to form), minerals from the water replace the atoms from what was left of the dead animal. This is called permineralization. In addition, the sediments that are surrounding the organism eventually turn to stone. So what is left is an imprint of the animal which is encased and preserved in stone.
Fossils do not preserve the whole body of organisms from the past, beside of exceptional situations. Because of their low resistance, soft tissues of plants and animals are naturally destroyed. In fossil rocks are usually found only parts of the hard tissues, mineralized, represented by wood tissue of higher parts of the plants, by protective coating in the form of shells of invertebrate animals or bones, which are constituting the internal skeleton of vertebrate animals. Primordial condition of fossilization is the burial as soon as possible, after the death, under a blanket of sediment. By burial,the organic debris are kept away from the oxidizing action of water and air, as well as necrophagous animals.