Role Of Male In Diversity Of Species By Dr.v.t

Role of Male in Diversity of Species Dr. V. T. Ingole

Although the origin of life on earth is a mystery, the evolution of so many diversified species and subspecies has been puzzling the evolutionists. The mystery is further deepened by the numerous varieties (more than billion) of living matter adapted to survive in water, land and air that too in the most extreme environment. The fundamentals of variation in characters of species could be explained by gene mixing as well as spontaneous mutations. Darwinian concept of survival of fittest is generally accepted for evolution and existence amongst such genetically mixed as well as mutated species. However, it remained unclear as regards to the present state of evolution of millions of living organism in such a short period (less than 3 billion years) as compared to the life supporting age (4 billion years) of the earth. From the early stages of life formation, be it a single or multicellular, the replication of cells comprising genes, the survival and further propagation have been responsible. There are two processes involved in life formation by cell namely mitosis and meiosis. In mitosis double stranded chromosome cells replicate in to similar double stranded chromosome cells whereas in meiosis double stranded chromosome cells are transformed in to a cell having only half the chromosome or single strand of chromosome. The former is the process wherein the number of chromosome pairs remains unchanged after replication whereas, in the later case a whole cell is formed from two cells each having half the number of chromosomes. It is known that during both the processes (mitosis, meiosis) mixing of genes and spontaneous mutation occurs. It has been postulated that mitosis was the only process of replication/propagation when life began on earth and is still prevalent in many of the unicellular and few multi-cellular organisms. Meiosis evolved at much latter stage of evolution. Let us try to understand these processes. The mixing of gene involves three processes such as: 1. Exchange of genes on the similar chromosomes within the pair (lateral). 2. The jumping of genes where genes exchange their position on the same strand of chromosome or within the pair. 3. In spontaneous mutation the genetic code changes within the gene. The first process brings in changes in the offspring more in physiological than anatomical. By the second process there are more changes in anatomical along with physiological. Whereas the by the third process there are likely to be radical changes in all the aspects. In mitosis the jumping and mixing of genes are regular as compared to spontaneous mutation however, as explained before the changes in the subsequent generations would occur only through such mutations. Normally genetic mutations do not occur concurrently but sequentially and governed by probability theory. Considering the number of species evolved and the duration of life supporting environment on Earth it appears improbable for the evolution by mere mitosis. In species of higher order like human mitosis takes place only 6 to 7 times in his lifetime. Considering multiple generations of replicated cells by mitosis the chances of genetic variation necessitates substantial period for present day picture of evolution. Similar phenomenon is observed in the surviving strains which become naturally immune to antibiotics/pesticides. In the reproductive cycle of certain gecko species only female is involved without male. Its eggs comprise all the chromosomes of the mother and the offspring are true replica of their mother genes. Such mechanism is some way simple however; the species are very susceptible to infections, environmental changes etc and only those would survive which are fittest as per

Darwin’s principle. If we substitute unicellular by multi-cellular then the period required for genetic evolution would go many folds due to higher age of maturity. It could be inferred from the foregoing discussion that the mechanism of evolution exclusively through mitosis is vulnerable and slow. If we consider the evolution another process of reproduction in the form of meiosis, perhaps this might give an answer to the faster evolution mechanism. This process is somewhat complex because it involves two similar species. Let us give a logical consideration to this process. For simplicity let us call the two species involved in meiosis as female and male. In meiosis reproductive cell are formed having half the chromosomes (one strand of double helix). The one, who has fewer reproductive cells (called female ovum), accepts external reproductive cells (called male sperms) and conceives. The advantage of this process over mitosis is that two separated partners are involved in reproduction thereby promoting the probability of increased gene mixing hence having offspring with varied characters. In certain species both parts are played by same specie known as hermaphrodite however, in breeding again two partners are involved. The danger of self breeding is circumvented by typical location of reproductive organs. In this process there is likely to be disadvantageous due to inbreeding similar to mitosis. Inbreeding means where female & male of close relations are involved in the reproduction in the breeding process. It is interesting to observe the number of ovum which is in less as compared to the number of sperms is many many fold. Female has one ovum per month as compared to 350000000 sperms per ejaculation. Theoretically as such there is a need of one to one ratio between ovum and sperm to satisfy gene mixing criterion then wonders as to why this ratio is deviated by nature to such a large extent? In the species of higher order it has been observed that the formation of ovum takes place during the embryonic development during pregnancy of the female whereas production of sperm in male is a continuous process during the matured life of male. The ovum is released for conception by female at a defined time or period whereas male sperms are ready all the time. In terms of probability the occurrence of mutation in female is rather less due to fewer numbers of ova whereas the probability of mutation in male has to be many many fold due sheer number of sperms. One has to consider the mortality of all these sperm cells as per survival of fittest theory. All such sperms are subjected to the test of survival by two forces such as intrinsic and extrinsic parameters. The intrinsic parameter comprises body temperature, immunity, antibodies etc. whereas extrinsic parameter comprises atmospheric temperature, oxygen level, altitude, pollution encompassing everything around including prevailing global and cosmic forces. Only those sperm would survive which are fittest to live in good and combat evil forces and pass on such competent genes to the next generation. In case of mosquitoes for example similar phenomenon has been observed where subsequent generations have become immune to DDT and many insecticides. Let us now give attention to the size of ovum and sperm. The size of ovum is more and hence less mobile whereas size of the sperm is very very small hence more mobile. It can be carried to a great distance by natural currents. Simple analogy can be given in case of dust and stones subjected to wind or water currents. Dust may cover very large distance as compared to stone. Such mobility on part of one partner not only avoids but mixing of varied sperms with varied ovum surviving in different environment globally. Secondly the energy of the sperm is limited and hence the ablest and strongest one would survive. And few amongst those would take part in reproduction. In conclusion it can be postulated that by the sheer large population of sperm the probability of mutant

sperm increases, the continuously produced sperms are subjected to global and cosmic environment hence they are time tested and due to their mobility they not only avoid inbreeding but fertilize most suitable ovum globally. Thus sperms are responsible for main genetic changes thereby enhancing the diversity of species in evolution. This way the time required for the evolution is cut down drastically. This probably is the answer to the question as to why meiosis was evolved. By this postulation one can account for the evolution of millions of species in rather short a period in relation to age of earth. We shall term such evolution as parallel evolution which to some extent answers the enigma of duration of evolution and life of the earth. Further reading: 1.The Selfish Gene, (Oxford Press) by Richard Dawkins 2.The Web of Life (Collins Publisher) by Fritj of Capra 3.The Blind Watchmaker (W. W. Norton NY) by Richard Dawkins

By Dr.V.T.Ingole ‘104’Ganerdiwal layout Camp Amravati Maharastra India -----------------------------------------------------------------------------------