When investigating the shells of the living things classified as mollusks, which live at the bottom of the sea, the form and the structure of the internal and external surfaces of the shells attracted the scientists' attention:

The internal surface is smooth, the outside one is fluted. The mollusk body is inside shell and the internal surface of shells should be smooth. The outside edges of the shell augment a rigidity of shells and, thus, increase its strength. The shell forms astonish by their perfection and profitability of means spent on its creation. The spiral's idea in shells is expressed in the perfect geometrical form, in surprising beautiful, "sharpened" design.

The shells of most mollusks grow in a logarithmic spiral manner. There can be no doubt, of course, that these animals are unaware of even the simplest mathematical calculation, let alone logarithmic spirals. So how is it that the creatures in question can know that this is the best way for them to grow? How do these animals, that some scientists describe as "primitive," know that this is the ideal form for them? It is impossible for growth of this kind to take place in the absence of a consciousness or intellect. That consciousness exists neither in mollusks nor, despite what some scientists would claim, in nature itself. It is totally irrational to seek to account for such a thing in terms of chance. This design can only be the product of a superior intellect and knowledge, and belongs to Almighty Allah, the Creator of all things:

"My Lord encompasses all things in His knowledge so will you not pay heed?" (Surat al-An'am, 80)

Growth of this kind was described as "gnomic growth" by the biologist Sir D'Arcy Thompson, an expert on the subject, who stated that it was impossible to imagine a simpler system, during the growth of a seashell, than which was based on widening and extension in line with identical and unchanging proportions. As he pointed out, the shell constantly grows, but its shape remains the same.

One can see one of the best examples of this type of growth in a nautilus, just a few centimetres in diameter. C. Morrison describes this growth process, which is exceptionally difficult to plan even with human intelligence, stating that along the nautilus shell, an internal spiral extends consisting of a number of chambers with mother-of-pearl lined walls. As the animal grows, it builds another chamber at the spiral shell mouth larger than the one before it, and moves forward into this larger area by closing the door behind it with a layer of mother-of-pearl.

The scientific names of some other marine creatures with logarithmic spirals containing the different growth ratios in their shells are:

Haliotis Parvus, Dolium Perdix, Murex, Fusus Antiquus, Scalari Pretiosa, Solarium Trochleare.

Ammonites, extinct sea animals that are today found only in fossil form, too, had shells developing in logarithmic spiral form.

Growth in a spiral form in the animal world is not restricted to the shells of mollusks. Animals such as antelopes, goats and rams complete their horn development in spiral forms based on the golden ratio.