Scientists at the University of Bristol in the UK found out, how did the various body plans (life forms) of animals. All these anatomical structures, there are several dozen. Article biologists published in the journal Proceedings of the National Academy of Sciences.
It is known that there is only a limited number of possible anatomical structures, and it is believed that all of them were implemented already in the early stages of life. A possible reason for this is a set of systems of gene regulation governing the development and structure of the body. However, another hypothesis is that new morphological forms may occur throughout the course of evolution.
In the new work, the researchers analyzed the diversity of life forms and came to the conclusion that many of the clades (group of organisms with a common ancestor) originally had a large number of anatomical structures. However, arthropods, chordates, annelids, molluscs and echinoderms continued to expand the range of forms throughout the Phanerozoic (542 million years ago to present), starting with the Cambrian period.
In addition, the apparent limitations arose because the intermediate life forms died out, as a result, the types of existing animals are very different from each other. The sheer increase in the number of anatomic structures has occurred due to the expansion of the genome and the emergence of new systems of gene regulation.
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