Brown algae of Phaeophyaceae class are a large group of eukaryotic plants, typical of coastal areas of the Baltic Sea, Atlantic Ocean and Pacific Ocean, late onset compared with other eukaryotic plants.

The biological tests of this late onset consisting of chloroplast existence surrounded by four membranes, in the existence of differentiated tissues and biosynthesis of organic iodine compounds and carotenoid pigments.

In this group are the Macrocistis, Fucus, Laminaria and Seytosiphon algaes that in 1812 were described for the first time as a source of iodine for the prevention of bone disorders. However Sydney Brenner, Robert Horvitz and John Sulston in 1965 showed that these algae also contained a carotenoid pigment fucoxanthin inducer of apoptosis.

Apoptosis is a process of cell differentiation very important in embryonic development and especially in the formation of the limbs. Thus fingers differentiation is only possible by the process of apoptosis.

A geological step back lets us know that fucoxanthin was present in the phycophyta algae from the Devonian 400 m.y.  ago

It would mark the following biochemical schedule:

(1) 400 m. y. existence of fucoxanthin and initiation of apoptosis in the inner extremities of littoral fish fins

(2) 245 m. y.  joint existence of fucoxanthin and iodine compounds and starting the development of external extremities in amphibians in lake areas.

The sequence of the appearance of phycophyta fossils, brown algae and extremities, first inner fins in the sarcopterygii and then outside in amphibians is new evidence of the link between dependence on cells and animal organs, and the molecules synthesized by the plant cells, in this case, through the epigenetic regulation of the expression of the Hoxd genes 10-13 as the basis for forming limbs through CsB switches.

Here is an example the development of frog tadpoles starting as a larva, without lungs and extremities, to an adult amphibian, with lungs and extremities metamorphosis in 90 days.

In the first phase (pre metamorphosis 20 days) herbivorous nutrition does not require specific nutrients, corresponding evolutionary age of fish. In a second phase (pro metamorphosis 20 days) requires a rich herbivory nutrition in iodine because the thyroid development is essential for the formation of limbs.

However sequence fucoxanthin (apoptosis) organic iodine (limb development) needs to be completed with the presence of calcitriol, which is synthesized in the animal body as Calcifediol as a result of parathyroid hormone that increases calcium absorption in the intestine.

In this biochemical triad found the origin of calcium metabolism in birds and animal nutritionist whose application provides advantages in bone development and egg production.