Roughness cover with small spikes the oldest of four-legged animals, apparently, had a remarkable feature - the removal of excess carbon dioxide from the body.
The results of the research presented by scientists in the Proceedings of the Royal Society B, may explain the gradual transition of some sea creatures to the earth’s way of life, which took place about 370 million years ago. They will also be able to reveal the cause of the appearance of the features of, in particular skin-bone coverage of these early animals.
"Dermal bones at the top of the skull and on the front of the shoulder is a common feature of bony fish, as they have flakes in the skin together with the components of dermal bones," said study author Christine Janis, told Discovery News.
Inspiration for the start of the study was 10 years ago when a co-author Daniel Warren noted that modern leopard frogs use bone area of the skin to buffer buildup of carbon dioxide. According to the researchers - frogs, turtles and caimans are doing the same.
Janice explained that all the birds, mammals and reptiles use special breathing edge to ventilate their lungs, allowing you to consume oxygen and produce carbon dioxide. Amphibian can not do this, but they are small enough so that they can be used to produce a skin CO2. Without such systems, the animals could die from the overflow of the body with carbon dioxide.
"If the content of CO2 in the blood increases, it generally comes in contact with water: H2O CO2 plus equals H2CO3, and a carbonic acid" said Janice.
Fish can get rid of CO2 through their gills, but the gills only work in water. Early tetrapods probably encountered many difficulties when they ventured to leave the water, probably lured by food. It would be like people suddenly forced to live in the ocean without the existence of the necessary technology.
As a result of these first quadrupeds being possibly developed bone and other non-structural mineral growths to neutralize the acidity. As you know - calcium and magnesium ions, when released into the blood, act as a buffer acidity.
The authors suggest that a direct proof of their theory can be obtained by identifying the chemical or structural component of bone in the skin of today’s animals that use it to neutralize the CO2 stored in minerals, and then find the same characteristics in the fossil record of early tetrapods.
Original: Physorg com