A review of Life Ascending by Rob Mason
Life Ascending: The 10 great inventions of Evolution by Nick Lane
“Where and how life has originated we do not know, but Nick Lane argues well for his view of marine alkaline vents as the cradle of life. He believes that the cell has been invented independently by bacteria and archaea.” Lars Olof Björn
“The Archaea constitute a domain or kingdom of single-celled microorganisms. These microbes are prokaryotes, meaning that they have no cell nucleus or any other membrane-bound organelles in their cells.” Wikipedia
In some systems for classifying all of life, the archaea constitute one of three great domains of living creatures. In 1977 American microbiologist Carl Woese, on the basis of analyses of ribosomal RNA, proposed that the prokaryotes, long considered to be a single group of organisms (essentially, the bacteria), actually consist of two separate lineages. Woese called these two lineages the eubacteria and the archaebacteria. These names were subsequently changed to bacteria and archaea (the archaea being distinctly different from bacteria), but Woese’s splitting of the prokaryotes into two groups has remained, and all living organisms are now considered by many biologists to fall into one of three great domains: Archaea, Bacteria, and Eukarya. Carl Woese
It is proposed that the pre-cellular stage of biological evolution unraveled within networks of inorganic compartments that harboured a diverse mix of virus-like genetic elements. This stage of evolution might comprise the Last Universal Cellular Ancestor (LUCA) that more appropriately could be denoted Last Universal Cellular Ancestral State (LUCAS). This scenario for the origin of cellular life recapitulates the early ideas of J. B. S. Haldane sketched in his classic 1928 essay.
In chapter 3, Photosynthesis, Lane starts the chapter: “Imagine a world without photosynthesis,” and goes on to tell us that it would not be green. He then goes on to say that: “Oxygen is the key to planetary life and is let loose by photosynthesis and subsequently energises all life. He further comments that: “nothing else can provide the energy needed to fuel the demands of multicellular life.”
This is definitely a fact filled book and provides the basis for understanding this subject. However I have included below some expanded details for some of the terms used in this chapter
Photo-synthesis is a compound word made up of two words, photo, which means light (it comes from the Greek word photos, and synthesis (which means "to put together"). An analogy might be the word synthesizer, which puts together different sounds to produce music.
Chlorophyll is a term used for several closely related green pigments found in cyanobacteria and the chloroplasts of algae and plants. Its name is derived from the Greek words chloros ("green") and phyllon ("leaf"). Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to absorb energy from light.
Light is a form of energy. Photosynthesis captures the energy from visible light but it doesn't use all of the light equally. It mostly uses light from the blue and red parts of the spectrum. Plants are green because chlorophyll reflects green light. And chlorophyll is found in all plants because it is the molecule that absorbs the light that is used to make sugar. . Being also responsible for almost all the oxygen in atmosphere, photosynthesis is the basis of all life on earth.
Chapter 4 - The Complex Cell - A fateful Encounter
Complex life did not emerge repeatedly from bacteria at seperate times. Plants from one type of bacteria, animals from another, fungi or algae from yet another. On the contrary, on just one occassion a complex cell arose from bacteria and the progeny from this cell went on to found all the great kingdoms of complex life. Nick Lane points to the eukaryotes as being the single most important cell to that transition. He believes that the the bacteria, mitochondria enabled the eukaryotic cell to evolve by providing a ready made system of internal energetic membranes along with the out posts needed to control respiration locally. The union relieved the energy constraints that forced bacteria to remain bacteria for all time.
The eukaryotic cell only evolved once because the union of the prokaryotes in which one gains entry to another is a truly rare event. A genuine fateful encounter resulting in all the marvels of the world.
Other chapters in this interesting book cover Sex, Movement, Sight, Hot Blood, Consciousness and Death.
Life ascending is not an easy book to read because of the need to obtain more supporting detail of the topic. However, if you have the time to do this it becomes more enlightening. One thing that must be acknowledged is the absolute dependence on chance. Nick Lane illustrates this point in a paragraph in the chapter entitled; Sex. He relates a conversation between George Bernard Shaw and a beautiful actress. We should have child together, the actress declares, ‘for it would be blessed with my beauty and your brains,’ Shaw replies by saying; ‘but what if it had my beauty and your brains?’
Shaw had a point: sex is the most peculiar randomiser of successful genes known.