God and Evolution

Many years ago I had a hard-working student who started by loving the introductory biology course I was teaching. We had started off with the section on unity, which emphasized the similarities in life forms from the point of view of cell structures and basic biochemistry. He had no issues with that. The next part of the course emphasized diversity. It was an introduction to classification and went on to elucidate different respiratory and digestive systems from the Haldane point of view that as things grow bigger, physical laws and surface-to-volume ratios force them to get more complicated. He still loved the course and continued to do well. The third theme was continuity. The intro to genetics was no stumbling block. But as soon as we looked at all the fossil and biochemical evidence of evolution, he looked depressed and withdrawn every second of every class. He later bombed his test on the topic. It wasn’t a case of correlation without cause. His parents were evangelicals, and they had taught him that evolution was the idea of the devil.

I tried explaining to him that many people of faith accept the evidence of evolution and continue to believe in God. But it was to no avail. Of course, since fundamentalists are not impressed with Catholicism,  it does no good to point out that in the 1950s in the encyclical “Human Generis ,” Pope Pius XII said that Catholic teachings on creation could coexist with evolutionary theory. Or that in 1996 Pope John Paul II admitted that evolution was “more than a hypothesis.” And since Darwin and Wallace started it all by proposing a mechanism, it doesn’t appease antievolutionists to point out that the two naturalists remained religious.

This memory resurfaced because I heard a former colleague say that she refuses to believe that we are intelligent monkeys. Technically she is right. We are not monkeys; we are more closely related to apes and you have to go further back in time to find a common ancestor between humans and monkeys than between humans and apes. But she just meant that she believed humans have always been the way they are now, ever since their “creation”. Somehow, she has been convinced that evolutionary theory is a form of political correctness. In her mind refusing evolution is somehow a sign of courage and ability to think freely.

I had previously pointed out that last century’s perverse idea of social Darwinism in no way discredited the idea that natural selection plays a role in evolution. But it did nothing to appease her irrationalism. I ultimately lost my patience arguing with her. Life is too short. That doesn’t help matters and neither do the arguments of atheists.

Let me explain why. Different world religions have different cosmology stories. The fact that they all contradict one another leaves one with at least a pair of possibilities. (1) They are all wrong and made up. (2) Only the one you grew up with is true. The second possibility is unlikely. Then there’s solid evidence from radioactive isotopes and half-lives about the age of the earth which reveal that the creation-numbers in the Bible are indeed fiction. Leaders of organized religion say that it’s the symbolism that’s important. What matters, they argue, is that God did create the universe. But the nature of God itself varies greatly from one religion to the next. In fact, the transition from polytheism to monotheism in many cultures was not based on new evidence. It’s not clear as to why it happened. From all this, atheists conclude that all religions are nonsense, and that there is no God.

Religious people find such a conclusion reprehensible. Given that most atheists accept the evidence from the theory of evolution, it’s inevitable that at least a minority of religious people will be even more compelled to throw evolutionary theory under the bus. ( 1/3 of all people in the United States reject evolution. )

One can construct a model of an evolutionary bush of life from cytochrome c, an almost universal electron exchanger in cellular respiration. Better ones have been constructed more recently based on 15 different ribosomal proteins common to all organisms. It suggests that bacteria is much more important and more evolutionary diverse than we imagined. The fact that a different model arises reminds us that we would have a better idea of life’s origins if we found more direct evidence from another planet—one where life just started. Antievolutionists exploit those uncertainties to jump to the dubious conclusion that it’s all wrong. But are atheists doing the same thing?

I do feel that it’s pretentious to anthropomorphize God or to try to package all our spiritual feelings and capacity for empathy and ethics into a single concept. But it might be equally pretentious to wish God and all religions away and to be convinced that we would be better off without these notions and customs. Taleb and others have pointed out that without religion, too many people find worse substitutes. Maybe it’s led to more worship of technology, more social fragmentation and more obsession with divisive politics.

“The fact that religions through the ages have spoken in images, parables, and paradoxes means simply that there are no other ways of grasping the reality to which they refer. But that does not mean that it is not a genuine reality. And splitting this reality into an objective and a subjective side won’t get us very far.”—Neils Bohr, 1927

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Why Potassium is Essential to Life

In life forms, in between cells, no other positive ion is more prevalent than potassium (K+) . The easiest way to collect it is from ashes. If you let water pass through a cloth holding ashes, the water will dissolve some of their compounds, especially potassium carbonate and create a yellowish solution. Evaporating the water will leave behind potash. This is where potassium got its name. If you dip litmus into a potash solution, it turns blue indicating the presence of a basic or alkaline substance. The K+ ion is not responsible for this. It’s the carbonate which snatches an H+ from water, forming bicarbonate and hydroxide. But since the metal will react with water to also liberate hydroxide, it is appropriate to call potassium an alkali metal.

Alqali (اَلْقِلْي ) in modern Arabic means frying. Most sources link it to saltwort, a plant whose ashes are rich in potassium carbonate. In any case, alkali is also the source of the German word for potassium, kalium, which lends its “K” to the symbol of the element and K+ to the symbol of the ion in ashes and rocks.

The concentration of potassium ions (shown as red dots) changes, depending on whether pores are open or closed. Source: Wikipedia commons

i.                   Why do plants have K+ ?

K+ is involved in the opening and closing of a plant’s pores(stomata). The concentration of potassium ions rises inside guard cells when stomata are open and drop when pores are closed. The ion also affects several enzyme systems and affects the shape of proteins, which is crucial to the function they serve.

Along with nitrogen and phosphorus, potassium is one of three elements most likely to be missing from agricultural soils and limit plant growth. Plants deficient in potassium ion have a hard time polymerizing sugars and amino acids into large molecules of carbohydrates and protein.  Depending on the species, leaves could go yellow or brown, their edges curl or their stalks become weak. Root growth can be stunted, and fruits and seed yield may diminish.

Why is the ion also essential to animals? Well, without it we can’t move, think or hear. Let’s see why.

ii.                 K+ ‘s Role in Nerve Cells

I once asked my dentist how an anesthetic works, and he did not know. That does not make him a bad dentist. So long as he knows how much lidocaine or articane to use and where and how to inject it, ultimately, it’s what matters. It is however another reminder of how scientifically uninquisitive we are as a society, regardless of the education level reached by an individual.

Potassium ion plays an important role in the transmission of nerve impulses, which are of course interrupted by an anesthetic . The axon, the long stem-like section of a nerve cell, is nothing like a copper  wire.  An axon does not easily allow electrons to flow through it. In fact, it does not rely on them at all to transmit impulses, which move more slowly than electricity.

The thick axon (0.5 to 1.5 mm) of the squid led to a classic study of how a nerve impulse  is sent along the length of the nerve cell. An oscilloscope was connected to microelectrodes to keep track of any build up of either positive or negative charges, which when separated create a voltage, also known as a potential difference. When both were inserted in different regions outside the axon, there was no voltage. But if one microelectrode was inserted inside the axon, it revealed a voltage of -70mV, revealing that the inside of the cell was negatively charged and that the outside was positive. This is known as the resting potential, the voltage in the absence of a stimulus.

A potassium channel has ATP-powered molecules than can draw K+ ions away from water’s pull and move K+ in and out of the cell. In contrast, Na+, which is smaller than K+, cannot be pulled through. Source: Max Planck Institute.

When the axon is stimulated by applying pressure, a small region experiences a reversal of polarity: the inside becomes more positively charged and the outside becomes more negatively charged. If the stimulus is strong enough to overcome a threshold level, that region will experience a short-lived spike in voltage that will be strong enough to cause neighboring regions to go through a similar experience, we have a so-called action potential.    

What is happening at the level of ions? What does potassium have to with it? In the resting state there is 30 times more potassium inside the cell than outside. The K+ ions are free to move in and outside the cell through potassium channels in the membrane, but an excess of chloride, negatively charged proteins and other organic ions keep the amount of K+ at steady state and keep the inside negative. There is also another channel that’s narrower and which potassium ions cannot cross. It’s the sodium channel, which is wide enough for smaller sodium ions to cross. But in the resting state, it is closed, and the exterior of the cell is stuck with 10 times as much Na+, which is why the outside is positive.

A stimulus changes the membrane’s permeability to Na+. With the “doors” briefly open, a small amount of Na+ ions (1 in a million) move in, drawn by the excess negative ions(protein  ions, hydrogen  phosphate and others) on the inside. During the short-lived inflow of sodium, known as depolarization , a very few potassium ions get repelled and pumped out of the cell, but overall the Na+-deprived exterior becomes more negatively charged, and the Na+-enriched interior becomes more positively charged. 

The sodium gates re-shut. But before the cell’s pump can restore the original concentrations of sodium and potassium to that section of the axon, some of the excess positive ions from the inside move towards the negative organic ions of a neighboring region. This change of voltage opens the adjacent Na+ gates leading to an action potential next door. The cascade of events is replayed until the nerve impulse  travels to the dendrites at the end of the neuron. Why does it move in only one direction? In each region, after a surge in negative voltage, the potential difference drops below the original resting potential. This region’s extra positive charge inside the cell makes sure that the nerve impulse does not travel backwards. 

In vertebrates, a “design”-modification makes the impulse travel faster. The myelin sheath has nodes, which are the only parts get polarized. Effectively, the impulses jump from one node to the next, skipping over parts of the axon. This means a shorter length of the axon must be repolarized; the ATP -powered Na+/K+ pump works less, and less energy is consumed.

At the nerve terminal, the impulse eventually causes the release of neurotransmitters. They move across the gap between nerve cells, and when they reach the receptors of the neighboring cell, they affect the permeability of the membrane. The permeability can either be increased, which will cause an action potential; or if the interaction is of an inhibitory nature, it will decrease permeability, preventing a stimulus from being effective.

Each of the dentist’s common anesthetics, lidocaine or articaine, temporarily block the sodium channel. Although inflicted pain still opens the floodgates, the sodium ion cannot enter and cause an action potential. Without an impulse, no pain is felt by the patient while the dentist is drilling and not thinking about the theory he learned back in college. 

iii.       Why We Need K+  in the Inner Ear

The ear is a beautifully intricate organ. The outer ear, which consists of the recognizable outer part and the external auditory canal, focus air pressure disturbances on the tympanic membrane, the so-called eardrum . The middle ear has three small bones that evolved from the jawbones of ancient reptiles. The area of contact between the eardrum and of those bones(malleus) is much smaller than the eardrum. The combination of that factor with the leverage of the malleus and the incus allow for very little force to do significant work on the oval window, the boundary between the bones of the middle ear and the fluid of the inner ear’s cochlea, a structure shared by all mammals.

Along the length of the coiled cochlea there are three canals.  The following figure reveals three cross sections of those canals. Notice how wide they are at the base, which is closer to the round window,

and how they get progressively narrower as they move towards the apex of the coil—to the left of the other two in the diagram. Between two of the chambers there is the basilar membrane which plays a crucial role in an organism’s reception of sound waves.  If you could roll it out onto a flat surface, despite the progressively narrowing canals of the cochlea, the basilar membrane becomes gradually wider. The base is stiffer, and the membrane gets displaced by higher sound frequencies, whereas the membrane at the apex is sensitive to bass sounds of lower frequencies. Intermediate frequencies affect corresponding parts in between.  But how do the stimulated parts of the membrane get their message to the brain?

If we continue our game of Russian dolls, where we find one doll within another, magnification of the surface of the basilar membrane reveals the Organ of Corti.  This includes two types of hair cells, which are connected to two types of nerve fibers whose message flow in opposite directions to and from the brain. Embedded in the tectorial membrane,  are the hair cells’ stereocilia. As sound frequencies move the fluid inside the cochlea, disturbing specific sections of the basilar membrane, the interconnected stereocilia of its hair cells get bent. 

Finally, we come to potassium ion (K+)’s role. The membrane’s hair cells are in the middle of the 3 chambers, known as the cochlear chamber, and it is filled with aqueous fluid rich in K+and with lower concentrations of sodium ion. If the cilia get bent towards the tallest of the structures, it opens the gates of the coiled structures (tip links) connecting the cilia. Potassium ion flows into the hair cells, depolarizing them. By a mechanism we shall reveal in a future blog, depolarization open calcium channels, which stimulate the release of neurotransmitters. As the latter flow to auditory nerve fibers, they get an impulse that’s relayed to the brain.

How to Make Magnesium With a Lower Carbon Footprint

Magnesium, the metallic element, is too reactive to be found in its unbound, elemental state. Not only does it react with air, but in the presence of acid, its loose electrons are snatched up by acidic ions and liberate hydrogen gas, leaving behind invisible ions of magnesium in solution. A similar but much slower reaction occurs in the presence of water. Although the ions generated in such reactions are far from being useless, the metal is also highly practical because it has a higher strength to weight ratio than aluminum(158 kNm/kg versus 130 kNm/kg). A high-strength aluminum alloy that’s used to make aircraft contains 2.5% magnesium. Magnesium also comes in handy when making other alloys for lightweight luggage, cases for electronics, textile machinery and that beautiful invention with a low-carbon footprint known as the bicycle. Cars have been made lighter, which improves mileage, thanks to the use of magnesium alloys in engines and other parts.  When including magnesium in cars, however, protective coatings are needed if the component will be in a wet, corrosive environment. In such conditions, when magnesium is in direct contact with other metals, it will act as a sacrificial anode, meaning that neighboring metals will be protected from oxidation but only at the expense of the magnesium part.

Magnesium is used in the alloy for some motorcycle engine blocks. (http://www.scienceimage.csiro.au/pages/about/)

How do we convert the natural ionic state of magnesium to the metal? There are two general approaches, each of which has a few different methods. Overall the methods are energy-intensive and leave a large carbon footprint. One approach is electrolytic and relies mostly on sea water and electricity; the second one called thermochemical uses rocks, heat and other compounds. The first approach which dominated magnesium production from the 1970s to the 1990s is based on Michael Faraday’s 1833 technique. His mentor, Sir Humphry Davy had announced that magnesium oxide was a source of a new element but without actually isolating it. Twenty years later, Antoine Bussy fused magnesium chloride with potassium metal to free magnesium for the first time. But later, Faraday isolated the metal by passing electricity through magnesium chloride, forcing the magnesium ions to be neutralized.

In the Dow Method, one of the ways of making magnesium electrolytically, shells, ocean water and lime are used to precipitate magnesium hydroxide, Mg(OH)2. Hydrochloric acid is then added to neutralize the solid and create magnesium chloride (MgCl2), which goes into solution. A lot of the water is evaporated off, and a concentrated solution of MgCl2 (35%) is purified and passed into electrolytic cells operating at 700 oC. There, at every electrode receiving electricity, magnesium metal is deposited. At every electrode returning electrons to the circuit, chloride ions are converted to chlorine gas. But the poisonous gas passes through a furnace where in the presence of steam, it reacts to form hydrochloric acid, which could be recycled back into the initial neutralization reaction.

Almost all the methods using the thermochemical approach begin with dolomite. In the Pidgeon process, silica and dolomite are first treated separately. The latter is heated and converted into a mixture of calcium oxide and magnesium oxide, while the silica is turned into a ferrosilicate using scrap iron and coke. After a few steps and at about 1200 oC, the ferrosilicate reduces only the oxide of magnesium, creating magnesium vapor, which can be cooled to the desired metal.

A comparison of magnesium-production’s energy requirements( GER) and global warming potential (GWP) to that of other metals. Image source: Magnesium: current and alternative production routes.  Conference: Chemeca 2010, At Adelaide, Australia

The Bolzano reactor. Source: Handbook of Extractive Metallurgy

The Pidgeon process became the dominant method (80%) after the 1990s as the technology became deployed on a massive scale in China.  But the electrolytic process has a lower global warming potential (GWP) compared to the Pidgeon process (47.3 kg of CO2/kg of magnesium to 62.7 kg CO2/kg of Mg).  In Canada, one company has managed to make the magnesium oxide-reduction part of the Pidgeon process twice as energy-efficient.

In another modification of the Pidgeon, known as the Bolzano Process, several modifications are made to the feeding apparatus, furnace shape and recovering operation of products. Briquettes of mixed dolomite and ferro-silicon are introduced into an electrically heated furnace under vacuum with only 400 Pa of pressure.  The GWP of the Bolzano process is only 33.2 kg CO2/kg of Mg about half of the traditional Pidgeon method’s footprint. Other sources suggest that the footprint might be as low as a 1/3, but that’s because hydroelectricity supplies 80% of energy for the process.

Unfortunately there is nothing in free trade agreements to ensure that the Bolzano process should be used over the less ecological methods.

Other sources:

Cherubini, F.  and al. LCA of Magnesium Production. Technological Overview and Worldwide Estimation of Environmental Burdens. Resources Conservation & Recycling, 2008, vol. 52(8-9), pp. 1093-1100.