Predecessors of Fishes, Jawless Vertebrates: Beginning of the way to man

The book about the jawless vertebrates (Agnatha) introduces the readers into the wonderful and little known world of oldest vertebrate animals. Till now they have not been considered in detail in the popular scientific literature. However just they, the Paleozoic agnathans, played a particularly important role in evolution of vertebrates. The jawless vertebrates appeared in the biosphere approximately 470 million years ago. They presented the basal morphological level from which the evolution began to form those vertebrates that surround us now and are known in fossil state: fishes, amphibians, reptiles, birds, mammals. The mammals comprise the man. For the first time we will see that the similar features are present in the morphology of the man and of ancient vertebrates (Diplorhina: Heterostraci). In the book the external view of Paleozoic jawless vertebrates, their external and internal morphology, relationships, evolution, mode of life, environment and causes of extinction are considered. The comparative material includes some other vertebrates, mainly old and contemporary fishes. For the first time the imprints of the brain of Paleozoic Agnatha (Diplorhina: Heterostraci) are compared to the brain of contemporary man. It is shown that the morphology of olfactory part of the brain and, on indirect data, the scheme of ontogenetic development of hypophysis (internal secretion gland) are similar in heterostracans (agnathans) and man. The fundamental characters of morphological similarity between diplorhina (Agnathans having two separate nostrils) and gnathostomes (vertebrates having jaws) are interpreted as an evidence of the close affinity of these groups. This conclusion does not coincide with another opinion widely spread in the scientific literature. Both points of view are
analysed in this book. It is shown that Diplorhina and man (humanity, species Homo sapiens) present the lower and the highest levels in direction of evolution: jawless vertebrates – Gnathostomes.
The important biological problems are discussed in the form of lively communication with readers. The book contains many illustrations including those which were made by the author.