RANDOM MUSINGS

MICROCOSMOS BY LYNN MARGUILIS
The book ‘Microcosmos’ by Lynn Marguilis and Dorion Sagan is one of the best reads for me in recent times closely following the book by James Lovelock on the Gaia hypothesis. The author removes humans from the high self-imagined pedestal of evolution and tramples upon them. They are bashed, abused, and totally battered into shame. We are hardly capable of surviving any catastrophes or holocausts. The bacteria have evolved into us and probably experimenting with the evolutionary mechanisms. If at all, it is a bad experiment and will not last forever. Our elimination would leave the biosphere to breath peacefully. Bacteria has been around for almost 4 billion years and are likely to go on for billions more. They have strategies for gene manipulation which includes the classical mutation but also horizontal transfer of genes and symbiosis. The horizontal transmission and mixing of genes is responsible to almost an infinite immortality of the species. The individual bacteria may divide but collectively, it is forever living. The rapid transfer of DNA across the entire species almost calls for a definition of a super-organism instead of single units. The common genetic pool with individual adaptations to the environment at local places has enabled the bacteria to be the sturdiest of all species.
The microworld of bacteria, algae, fungus, and planktons have actually interacted with the environmental inanimate matter leading to a very stable biosphere with just the right conditions of life. If the life is absent in these forms, Earth would have been like Venus or Mars, either too hot or too cold. The temperatures, salinity of oceans, rainfalls, richness of the soil, the fixed composition of atmospheric gases suitable for life, all are a consequence of the richness and the complicate interactions between the microbial world and the environment. Life cannot be seen in isolation but is a complicated web of interactions. It is difficult to say when inanimate matter ends and when life begins. It has been appropriately named the web of life. She compares this to the human body, where each organ is functionally separate but form the complex whole. Like the RBC which travel to distant parts of the body and serve them, the bacteria similarly carry information in a fluid manner across the whole biosphere.
Superimposed on all these is an important process called symbiosis. The mitochondria in each cell is actually a foreign bacterium which have got incorporated into all the eukaryotic cells and helped in the consumption and utilisation of oxygen. At one point in Earth’s history, the atmosphere was bereft of oxygen and all the organisms were surviving on anaerobic metabolism. Then, there was a huge output of oxygen suddenly which led to a mass extinction of almost all species who were exclusively surviving on anaerobic mechanisms. The bacteria did not die, of course. The symbiotic union of oxygen utilising DNA helped in a conversion from anaerobic to aerobic metabolisers.
Symbiosis is a very important mechanism for the purposes of evolution. The amazing fact of the human body is not only we are composed of 90% bacterial cells, but every human cell is containing a microbe in the form of mitochondria. There is all evidence to show that the mitochondrial DNA entered a remote ancestral cell of humans and formed a great symbiotic whole. The mitochondria get protection from the outside world; food from the waste of the cellular mechanisms; and in return produces ATP, the energy source, from oxygen. Oxygen at one point of time was the most toxic of all elements in the atmosphere and it was this useful union with the mitochondrial DNA that allowed survival of the species and future evolution. The author suggests at one point delightfully that bacteria have actually evolved into us.
Like the mitochondria in all nucleated cells, the chloroplasts in plant cells which is vital in photosynthesis is in all probability a bacterial DNA which got incorporated. The symbiotic nature in the plant cell is now responsible for the whole life on Earth. A very important speculation which seems to be eagerly investigated is the possibility of the microtubules in each cell as being of spirochaetal origin which got integrated into the human cell. The microtubular system is extremely important for all cellular processes where it creates actually mechanical paths for intra-cellular transport. The mitotic and meiotic divisions of the chromosomes is an intricate play almost akin to a ballet based on the microtubular strands. The movement of the cells, especially the sperms where the tail is very important for forward movement is based on the same DNA. This particular DNA which is responsible for cell movement, intra-cellular transport has independence from the main nuclear DNA, just like the mitochondria and the chloroplasts. So, the shocking aspect of humans is that we are 90% bacteria, only 10% actually is comprised of human cells. And further, each human cell is composed of bacteria derived organelles having some extremely vital functions. It is rather a humbling thought.
So, there is an entire paradigm shift from competition to co-operation in the process of evolution. She then defines sex as intermingling of genes and in this basic definition, reproduction as we know is not required. In fact, the ultimate purpose of life is to create copies of itself and the means of sex in humans is very cumbersome. The process of meiosis, the choosing of partners, the act of reproduction at the correct time of ovulation, the long time spent in the womb are all very detrimental to the process of survival and propagation. It is a very long and a bumbling process guaranteed for a lot of failures. However, this long period of maturation has allowed intelligence to evolve fully. Survival in strict Darwinian terms is fecundity, that is the amount of progeny one produces. In this regard, humans are distinctly at a disadvantage. The most rapid sex is in the bacteria which divide once every 20 minutes and the rapid exchange of DNA in a horizontal method ensures almost a super-organism spread across the globe. The only thing which is popular about human reproduction is that it happens to be pleasurable, but apart from that, there are no survival advantages in the human mode of reproduction. The pleasure aspect has allowed it to become very popular. But in most living world, it just goes on in a matter of fact manner without much ado. The bacteria are practically infinite in its living.
Water is an important component in humans. We have all come from water of the seas and the oceans. Our cellular composition and the extra-cellular composition is very close to the sea water composition. It is also a reminder of watery origins when the sperms and the eggs actually meet in a very fluid environment swimming towards each other and the nine months which are spent after fertilization surrounded by the amniotic fluid.
The microtubules in the brain may be actually responsible for intelligence and recent theories are talking about the quantum jiggling of these microtubules as a mechanism for consciousness. This leads to a shocking scenario where intelligence and consciousness may be of bacterial origin! In the final part of the book, the authors become highly poetic and thrash human beings as an evolutionary dead end. The humans either can fight with the nature and perish, or they may become too adapted to the environment and perish. But perish they will, if the present scheme of things and the philosophy of competition, struggle, fight, domination, and brutality continues. The human beings are a mammalian weed as she calls them, who have grown purely by an accident of evolution. We are neither required nor important in the scheme of life on Earth. The bacteria by symbiotic equations have led to us but we are in the process of using technology and genetic engineering to accelerate the process of evolution. Maybe, it is good if the ultimate goal of bacteria is to spread to other planets and solar systems and live forever. The bacteria are probably using the human body to spread outside the Earth and become a forever living unit despite the Earth being roasted and blown up after some millions of years. This is because 90% of the human body is bacteria and it is an impossibility that we can spread to outside of Earth in isolation of the bacteria. We have to take them along with us. But there is a grave danger from the way we are going that we would be extremely dangerous to the survival of many species. We are a bacterial symbiosis gone wrong.
The book is very thought provoking and reads almost like an Alistair MacLean thriller. This is quite an achievement for a book on evolution. It is a must read for everyone to open the world around us in a grand manner. There is too much of Darwinism and hard-boiled Dawkinism going around leading to a rather one-sided view of the whole scheme of evolution.