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Unless otherwise indicated all photos © Richard McKie 2005 - 2019

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Back in 2015 a number of friends and acquaintances told me that Climate Change is a myth.

Half a decade on and some still hold that view.  So here I've republished a slightly longer version of the same article.

Obviously the doubters are talking about 'Anthropogenic Global Warming', not disclaiming actual changes to the climate.  For those of us of a 'certain age' our own experience is sufficient to be quite sure of that the climate is continuously changing. During our lifetimes the climate has been anything but constant.  Else what is drought and flood relief about?  And the ski seasons have definitely been variable. 

Beyond our direct experience everyone, including Greta Thunberg, has to rely on others: parents; teachers; books; and so on.

Some things confirm what we are told others do not. So I like to let the grandchildren play with my microscope to see for themselves. Similarly, the existence and complex functioning of your mobile phone confirms much of modern physics in a single device and quite a bit of chemistry too. But it's existence is a bit ambivalent on the accuracy of ancient climate history. So for that I must rely on the reports of scientists who have themselves examined ice cores or tree rings or sea level records or other physical evidence that can be dated.

So I'm prepared to believe aspects of quantum theory and I'm prepared to believe the scientists who have determined sea levels showing that fourteen or fifteen thousand years ago a hypothetical Australian could walk from Hobart to New Guinea or an Irishman all the way from Galway to Denpasar in Bali.  Indeed it now seems likely that our Denisovan cousins/ancestors did exactly that during a cold snap around 65,000 years ago. Yet I'm a bit sceptical when it comes to the attributes of the god Ganesha or the efficacy of prayers to St Anthony.

 

Changing sea levels during the past 20,000 years
 Source Wikipedia: Early Human Migration & Sea Level change

 

It seems to me that this rise has not stopped.  During my lifetime the average sea level in Sydney Harbour has risen by nearly a foot, in keeping with long term trends.  More water in the Harbour on average obviously has temperature and therefore microclimate implications.  There are thousands of well documented examples of changes like this that have climate impacts.

But like the tides there is great variability that masks the underlying trends.   For example 2014 was a record warm year in Sydney.  But in mid 2015, when climate scepticism was at a peak, we were going through the longest cold spell in 45 years.  It snowed in Queensland!  Now in 2019 we, like California, have high temperatures; little rain; and the worst bushfires ever.

Notwithstanding this variability, sea level rise shows that the planet has been getting warmer for at least twenty thousand years and the trend continues.

So there is no doubt that climate changes and that the earth's surface is presently getting warmer.  The only debate possible concerns the impact mankind is having on this change. 

This debate goes to:

  1. how significant has the impact on the planet of our various activities already been;
  2. how significant might our influence be in future;
  3. and given that we are experiencing changes is there anything we can do to mitigate negative impacts or perhaps exploit the changing environment?

These are the same issues that I addressed in 1990 in my paper: Issues Arising from the Greenhouse Hypothesis that you can still read on this website.

As I have written and said repeatedly since, although the climate has changed nothing much has changed about the climate debate.

Let's reprise some of the key evidence.

Among the symptoms of mankind's impact on the planet is the extraordinary recent rise in the levels of carbon dioxide (CO2) in the atmosphere. 

co2 data mlo
Source: NOAA - Global Greenhouse Gas Reference Network
 

This is of concern because over the past four hundred thousand years there has been a close correlation between global atmospheric temperature rise and higher levels of CO2 in the atmosphere.

 

Vostok Petit data Graph of CO2 (green), reconstructed temperature (blue) and dust (red)
from the Vostok ice core for the past 420,000 years
Source: NOAA derivative work: Vostok-ice-core-petit; in Wikimedia Commons

 

 

Other, shorter term records like tree rings and stalagmites confirm this close correlation between temperature rise and CO2 levels. 

But ice cores are one of the best tools for looking back into the past as they contain both dust and air bubbles trapped when the snow fell and in some places, like the Antarctic, the layers of snow have been building up relatively undisturbed for tens of thousands of years.

The above ice core data shows that for half a million years, until the the middle of the last century, CO2 levels fluctuated widely but never exceeded 300 parts per million (ppm).  We broke this half million year record in the 1950's.  So we have been in unchartered territory since then.  As I said in my 1970 paper it is probably already too late to correct the damage already done.

Yet in mid 2015 Atmospheric CO2 went past 400 ppm and if anything its rate of rise is accelerating.  Some think that this is approaching the highest level since the Carboniferous Period, over 300 million years ago.

This alarms most observers.  Should you be worried?

"Not at all," say some of our radio and TV 'shock-jocks'. 

Many in the good old USofA agree with them. After all God - or the gods, depending on our upbringing - put us here with a purpose. Thus He or they looks after us all individually.  It must all be part of a mysterious 'Plan'.

So there must be some mitigating consideration not immediately obvious, a: 'get out of jail' card?  A literal 'Deus Ex Machina'.

Possibly say some the core data contain a silver lining? The ice core data shows that higher atmospheric dust correlates to lower temperatures. It has been demonstrated during recent events that dust in the atmosphere, from volcanoes meteor impacts, large fires and so on, reflects sunlight and lowers global temperature. Historically when this happened possibly as a result of fires and volcanoes that release CO2, CO2 levels actually fell, in line with the drop in radiant absorption.  So if the worst comes to the worst maybe we can deploy a protective dust layer or some sophisticated orbiting 'parasol' to moderate incoming radiation?

Others say: "What's carbon dioxide anyway - a tiny fraction of the atmosphere?"  "Maybe," say some, "CO2 levels have nothing to do with anything?"  Yet this ignores both theory and numerous experiments that demonstrate a causal relationship between 'greenhouse gasses' and the rate of temperature rise. The affect of various gasses, CO2 amongst them, has been measured and confirmed repeatedly. So it's not irrelevant.

Some critics doubt the data altogether and claim that the researchers are seeing what they want to see.  Yet there are now vast amounts of supporting data.  So this argument is difficult to sustain. 

Could atmospheric temperature determine natural CO2 levels, not the other way around?  I canvassed this possibility in my 1990 paper but a moment's glance at the data dismisses this possibility.  The climate has been hotter several times in the past half million years yet CO2 levels have never been as high as they are now.

Some might observe that correlation does not imply causation. So can we rely on the historical correlation at all?  Plausibly both changing temperature and CO2 levels are a response to something else, like changes in the carbon cycle of plants and animals or our orbit relative to the sun and moon or corresponding changes in ocean currents.  Again, I canvassed this possibility in the 1990 paper.

Over 400 thousand years the earth's surface has changed significantly.  Plants and animals and the area covered by water have been in constant flux.  Just 40 thousand years ago there were still mammalian mega-fauna and huge herds of smaller beasts pursued by sometimes frightening predators competing with early modern humans and other hominids like the recently discovered Denisovans.  The carbon cycle and atmospheric water vapour (clouds) must have varied too. Agriculture where it existed at all was once limited to small gardens. Now our engineered crops cover much of the planet.    

As you can see from the graphs based on ice cores CO2 has shot up steeply in the past ten thousand years, that correlates with the rise of human civilisations, and you can see from the Mauna Loa data that it has not stopped. 

Critics of the prevailing scientific view argue that if CO2 in excess of 260ppm causes accelerated warming, CO2 levels above 300ppm since the 1950's should have already resulted in much faster warming than we are actually experiencing.

Other critics suggest that the prevailing climate models are faulty because significant negative feedback effects have not been properly accounted for.  For example: water vapour may play a greater part in reflecting sunlight back into space than accounted for.  And maybe recent human activities, like aircraft vapour trails are having much greater than expected cooling effects. 

Given the evident lag in predicted warming I find this argument quite persuasive. 

It's clear that majority of climate scientists argue that temperature will indeed rise steeply as a result of higher levels of CO2.  Many argue that the reason that rapid rise has not been relatively small to date is that the impact of high CO2 has a lag of many years before it takes effect.  I'm not convinced by this lag theory and think other factors such as water vapour must be at play.  If it's all going to ocean warming Sydney Harbour should be a lot more than a few inches higher. 

But Science is not a democratic process.  You can't determine facts by taking a vote or counting up scientists. The history of science is littered with examples of lone voices who turned out to be correct in the face of accepted orthodoxy. 

Today scientific orthodoxy is reinforced by the peer review process; the need to get a higher degree then attract research funding and career support. This results in a natural tendency to accept the present paradigm in the scientist's field of study. Rebels who turned out to be right have often been cast out, losing financial support, their job and their livelihood.

Having said that, those few rebels who turn out to be right are generally very well read, carried out novel experiments or observations and were among the most experienced in their field.  Galileo is an example and Darwin spent many years of detailed experimental work confirming he was right before he dared publish his, then, controversial theory.

It is extremely unlikely that a journalist, shock-jock, casual observer, theologian, businessperson or politician is actually a modern day Galileo, a voice of reason in a sea of conformity.  Historically it was these very popularists who were at the head of the mob suppressing books or demanding that the malefactor be brought before an Inquisition.

I've spent the past thirty years listening to this debate. One thing I can see for myself is that the harbour is a little deeper.  Another is that there are now nearly four times the number of people to feed, house and support, with increasingly complex goods and services, as when I was born.  Otherwise I'm not a lot wiser.

But I've recently done quite a bit of travel and I am certain that humans are altering the planet in other ways, that are much more obvious than global warming.  More than three times more humans have inevitably resulted in massive differences, including to micro-climates, in the past seven decades. Pay a visit to Morocco or Uzbekistan.  But has human life improved overall?  Maybe, for us in Australia, but not globally. In some places, like Egypt, it is noticeably worse. Even in Europe some would make that claim.

As travel or Google Earth quickly reveals, humankind has already devastated vast areas of the planet to meet our many needs - destroying the natural balance everywhere you look.  This devastation is set to grow by at least half as much again by the middle of this century.

As I said at the outset, for things we can't see for ourselves we must rely on the expertise of scientists, so it's easy for some to gainsay the climate data.  Yet we can all see, before our own eyes: relentless urban sprawl; houses burning on the fringes, where once there was only bush and pavements clogged with humanity, where once one could stroll unjostled.  As Joni Mitchell sang in 1969: “They[ve] Paved Paradise and Put in a Parking Lot.

But it's not just scientists or readers of 'New Scientist' who know that the planet is in serious trouble. We just have to listen to the news to know that numerous species are extinct or close to extinction; the number of small birds is down dramatically, possibly because the number of insects, including important pollinators, has also been in freefall and that the planet is increasingly drought affected with drinking water at a premium. 

These changes are often put down to climate change alone.  Yet, like anthropogenic climate change itself, they are but symptoms of the most obvious reason of all.  There are already too many people (anthrops) competing with the other higher life-forms for the earth's resources and more every day.

At the beginning of the 19th Century there were less than one billion people on the planet, an estimated doubling over the previous five thousand years. The human population took well over a hundred years to double again, so that in 1945, the year I was born, the global population had just passed two billion. Now, heading into 2020, we are approaching eight billion humans competing for the earth's resources. We've added almost six billion during my lifetime. 

As far back as 2013 a Global Hunger Summit in London(2) was told that: 'Malnutrition is the underlying cause of death for at least 3.1 million children [per year], accounting for 45% of all deaths among children under the age of five and stunting growth among a further 165 million [children].'

It's an outcome correctly predicted in 1968 by Professor Paul Ehrlich, of Stanford University in the US, in his book: The Population Bomb.

Had it been acted upon then there would be a lot less of us to compete for limited resources and a small fraction of today's number would be starving.  But starvation is but one outcome. People who have become victims of the 'Population Bomb' also endure lifelong misery and suffering including: stunting; brain damage; illiteracy; ignorance; tribalism; corruption; exploitation; and brutality. Pope Francis has a little list.

Some nations that did act to curtail fertility, like Singapore; the other 'Asian Tigers'; and China, made successful transitions from third to first-world economies, albeit with some adverse demographic consequences as a result of a cultural preference for male children.

Unlike China, where compulsion was more draconian, Singapore ran a media campaign 'Stop at Two'. This was supported by state supported birth control for women and voluntary male sterilisation.  Active suasion was limited to ineligibility for public housing and denial of some other social services to families with more than two children. Fertility dropped from an unsustainable 4.7 in 1960 to to less than replacement level twenty years later, with growth now due to extended life expectancy. They now have the fourth richest people, per capita, on the planet, demonstrating that population growth is not an essential component of economic development.

Similar efforts elsewhere were sabotaged. The present and ongoing human tragedy in the rapidly growing populations of the third world is a direct outcome of deliberate and active opposition to efforts to control human fertility, perpetrated by a number of institutions, during the latter part of the 20th Century*.

It's glaringly obvious that we are now suffering a wide range of impacts on our environment, of which the extraordinarily high level of CO2 in our atmosphere is but one symptom. 

We may, or may not, suffer catastrophic carbon dioxide induced climate change but it seems we can do little about the real 'elephant in the room', our now enormous population, that despite slowing growth in nations like Singapore, Korea, Vietnam, Taiwan, China and even in the Kerala region of India, will soon approach ten billion, and the vast consumption of resources, and inevitable depletion, that such a population entails. A liveable climate is just one such resource. 

As we approach ten billion this disease is going to get a lot worse, yet we seem to be fixated on just one symptom.

Carbon free energy is a trivial problem in comparison to deficiencies in several other recourses, including fresh water and arable land.  Energy is one of the most plentiful resources. There are now many ways of freeing or collecting it available to modern engineering.  Wind, solar and hydraulic (dammed or run-of-river) and nuclear energy are already used extensively and tides, wave, and geothermal resources can assist in appropriate locations. It's just a matter of cost.

Like nuclear power, the energy cost of renewables is entirely due to the actual (whole of life) cost of transforming and delivering the energy to consumers. This is the cost of the equipment required and the salaries of people required to maintain it and dispose of it when no longer economic. Henceforth this energy needs to be, as far as possible, carbon free. As it is entirely a cost issue, provided there is no political interference, like restricting nuclear energy or imposing aesthetic standards on wind farms, a suitably structured energy market can be relied upon to determine the best mix of technologies to deliver the least expensive solution. 

As I have previously written (back in 1990) if we are to save human civilisation from catastrophic collapse we must urgently start transitioning to a declining world population. To do that we will need vastly more energy to lift the living standards of the huge proportion of people condemned to poverty as a result of their ancestors' excessive procreation. 

Possibly anthropogenic climate change is a myth. Unlike the shock-jocks, I'm no self-appointed expert on solar absorption or the radiant quality of clouds. Yet in the, highly probable, event that the model supported by most qualified climate scientists is right, atmospheric carbon dioxide at over 400ppm is already far too high and going higher. And if we passed the safe level not long after I was born it's already too late to do anything about it. Based on that model a rise in global temperature, more than sufficient to devastate presently located agriculture, seems inevitable. 

In this event, the present daily starvation rate will rise to levels that will precipitate economic and social collapse in many countries. 

Notwithstanding that scenario. One thing I'm sure of is that there are a lot more people to feed now than when I was a child and that this will continue to get more acute - until, as in a mouse plague, it becomes self-correcting.

Let's hope my sceptical friends and the believers in a benign, all-powerful God are right and the majority of climate scientists is wrong.  In any case the world is in for a bumpy ride over the next few decades.

I commend my 1990 paper: Issues Arising from the Greenhouse Hypothesis to you. 

 


* In the 1960's it was already evident that the human population was growing at unsustainable levels. But the Vatican went on an active campaign to circumvent any attempts to limit world population. In interviews with the The London Times (newspaper) in October1970,  The Vatican Secretariat for Unbelievers told The Times: "The official Catholic policy influences through Catholic political power to a high degree the policy of nations - even if the Catholics represent a minority of the population...  "The Vatican resists all efforts to develop a system of world population control. It rejects contraceptives, sterilisation and abortion."

In 1974 United Nations proclaimed World Population Year.  As predicted, this was opposed vigorously by the Vatican using every tool and influence at its disposal.

The International Humanist and Ethical Union reported that year: "This spring the Vatican has started a campaign to propagate its viewpoint on birth control. Thus it takes an overt stand against the 1974 World Population year...."

In the US, where Protestants outnumber Roman Catholics by more than three to one,  fundamentalist Protestants nevertheless conspired with Catholics to prevent US Aid being linked to population control programs or incentives.

As recently as 2010 Catholic On Line website hailed World population growth as a positive outcome:  'Vatican stats: Catholic Church growing, especially in Asia, Africa'.

So keen on eliminating any form of birth control that until late 2009 the Vatican continued to assert that condoms don't protect against Aids. The article 'Church in Africa continues AIDS fight without condoms' could still be found at http://www.cathnews.com/news/310/53.php until that time.  But in 2010, in the face of tens of thousands of the faithful dying of aids in Africa these claims disappeared and the policy was miraculously reversed.  Now condoms could be used to stop disease but not to prevent conception - an interesting paradox.  Do people have sex to risk disease?

But it is unfair to put these thousands of miserable deaths from overpopulation, each hour of every day, entirely at the Vatican's door. Islam (although there is no single organisation heading that religion that forms an easy target) is equally to blame.  Its treatment of women as 'baby machines' has resulted in unsustainable population growth in the middle east and Islamic Africa that is a significant factor in current wars and instability in the region. See my travel diary on Egypt Syria and Jordan.  

In 2015 Pope Francis' Encyclical sounded a belated note of alarm at humanity's impact on the Planet, outcomes for which the actions of his church, together with the other institutions actively subverting past efforts at population control, is substantially responsible.

 

 

 

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Travel

Laos

 

 

The Lao People's Democratic Republic is a communist country, like China to the North and Vietnam with which it shares its Eastern border. 

And like the bordering communist countries, the government has embraced limited private ownership and free market capitalism, in theory.  But there remain powerful vested interests, and residual pockets of political power, particularly in the agricultural sector, and corruption is a significant issue. 

During the past decade tourism has become an important source of income and is now generating around a third of the Nation's domestic product.  Tourism is centred on Luang Prabang and to a lesser extent the Plane of Jars and the capital, Vientiane.

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Fiction, Recollections & News

The Time Lord

 

 

 

For no apparent reason the silver haired man ran from his companion, shook a tree branch, then ran back to continue their normal conversation. It was as if nothing had happened. 

Bruce had been stopped in peak hour traffic in the leafy suburban street and had noticed the couple walking towards him engaged in good humoured argument or debate.  Unless this was some bizarre fit, as it seemed, the shaken tree branch must be to illustrate some point.  But what could it be?

Just as the couple passed him the lights up ahead changed and the traffic began to move again. 

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Opinions and Philosophy

The Chemistry of Life

 

 

What everyone should know

Most of us already know that an atom is the smallest division of matter that can take part in a chemical reaction; that a molecule is a structure of two or more atoms; and that life on Earth is based on organic molecules: defined as those molecules that contain carbon, often in combination with hydrogen, oxygen and nitrogen as well as other elements like sodium, calcium, phosphorous and iron.  

Organic molecules can be very large indeed and come in all shapes and sizes. Like pieces in a jigsaw puzzle molecular shape is often important to an organic molecule's ability to bond to another to form elaborate and sometimes unique molecular structures.

All living things on Earth are comprised of cells and all cells are comprised of numerous molecular structures.

Unlike the 'ancients', most 'moderns' also know that each of us, like almost all animals and all mamals, originated from a single unique cell, an ova, that was contributed by our mother.  This was fertilised by a single unique sperm from our father.

This 'fertilisation' triggered the first cell division. These two cells divided; and divided again and again; through gestation and on to birth childhood. So that by the time we are adults we've become a huge colony of approximately thirty seven thousand billion, variously specialised, cells of which between sixty and a hundred billion die and are replaced every day. Thus the principal function of a cell, over and above its other specialised purposes, is replication. 

As a result, the mass of cells we lose each year, through normal cell division and death, is close to our entire body weight. Some cells last much longer than a year but few last longer than twenty years. So each of us is like a corporation in which every employee and even the general manager has changed, yet the institution goes on largely as before, thanks to a comprehensive list of job descriptions carried by every cell - our genome.

Cell replication is what we call 'life'.  The replicating DNA molecule can therefore be regarded as the 'engine of life' or the 'life force' on Earth.  So it is quite a good thing to understand. 

 


What makes us human?

Different animals and plants have different numbers of genes and chromosomes that together make up their genome.  Many are far more complex than humans.  The 32 thousand  human genes are organised into 23 pairs of chromosomes within each of our cells.  But the protein-coding genes, that differentiate us, form only a fraction (about 1.5%) of the instruction and memory data that is stored in DNA. The remainder, coding for other aspects of cell chemistry, seems to be administrative overhead.

When human girls are born, they have about a million eggs in each of their two ovaries, nestled in fluid-filled cavities called follicles. But this number declines quite rapidly so that it is depleted by the time of menopause (usually before 50 years of age). Unless fertility treatment is in use, just one or sometimes two of these (apparently randomly selected) ova descends from the ovaries each menstrual period - down the woman's fallopian tubes where it (or they) may become fertilised if the woman has recently engaged in coitus (had 'sex').

As in vitro fertilization (IVF) demonstrates every day; we now understand that a unique version of your father's genome was injected into your mother's egg by just one of his millions of spermatozoa. So that when the two genomes merged a doubly unique cell, that became you, was the result.

Our genes, that are encoded in their DNA, come in equal proportion from both parents.  Unless we have an identical twin, resulting from division of the zygote (see below) after fertilisation, each of us is genetically unique; our genetic identity determined by that successful fertilisation. 

 

 


Human Reproduction - Click here to Expand

 

Within our species we are said to be of Caucasian or Asian or African appearance, to have dark or fair complexion and so on, and possibly to bear a ‘family resemblance’.  These traits are due to the particular gene variants we have inherited from our parents.

These have been passed down to us, with regular variations, from parent to child, and through many ancestor species, since life began on the planet. And all plants and animals on Earth belong to a single family because we all inherit the same system of reproduction from one original replicating cell, our last universal common ancestor (LUCA) 3.5 to 3.8 billion years ago.

 


Replication

The DNA molecular structure resembles a zip fastener, where each tooth can be any of four molecular bases.  The bases G-C and A-T are each small organic molecules that at one point are covalently bound to a triphosphate (containing three phosphorous atoms) and a sugar group that binds them in a ribbon.  At their free end Guanine is attracted to Cytosine, with triple hydrogen bonds, and Adenine is attracted to Thymine, with double hydrogen bonds. 

In the following notation: black = Carbon;  blue = Nitrogen;  red = Oxygen; white = Hydrogen.   Bars joining them indicate a covalent bond, an electron shared between the atoms.  A double bar indicates two shared electrons.   

 

  Cytosine (C4H5N3O) has a shape that attracts (fits)   Guanine (C5H5N5O) 


but not  Thymine (C5H6N2O2)  or   Adenine (C5H5N5), that attract (fit) each other.

 

Each of these bases is bound to a ribbon of  sugar molecules and at its other end lightly bonds to a matching base on the other half of the 'zipper' such that when it is 'unzipped' each attracts its opposite number (like magnets attracting the opposite pole) thus recreating a new matching half in the same sequence.

 


DNA replication. 

 

This unzipping and reforming is called self-replication. It is going on continuously in all living things as new cells are created to replace those that die. In an adult human around three quarters of a million of our cells divide every second.  This cell division is the process we call organic life and may continue (usually briefly) after we are legally (brain) dead.

Other chemical mechanisms within the cell translate the genetic information stored in the DNA sequence to manufacture the proteins from which new cells are built and differentiate themselves, organising to become our various organs and to thus arrange themselves to form a human; and not a gorilla or a crocodile or a kola or a rose or a cabbage. The human genome project had now identified 32,185 human genes.

Accurate reproduction is very important to the viability of an organism.  Just as: 'WOLF' does not have the same meaning as 'FOWL' the location and order of sequence G-A-T-C within a particular DNA string (chromosome) will result in a different outcome to the sequence C-A-G-T .   And this difference will influence cell structure and purpose:   'The wolf eats the fowl' has a totally different meaning to: 'The fowl eats the wolf'.

This method of storing and reproducing instructions and data is twice as efficient as the binary method we presently use in electronic devices.  For example the binary processor in your computer or reading device requires each character in in each word in this sentence to be encoded in two bytes (each of 8 characters or bits).  In other words 16 ones and zeros are required for every character on this page (eg 'a' = 0000000001100001) and a similar number for each pixel in a simple colour image.  But DNA can encode the same information (sufficient for every unique character and symbol in every language in the world) in just eight characters.

There are a fraction over 3 billion characters in the human genome (3,079,843,747 base pairs).  In computer terms this is equivalent to about three quarters of a gigabyte of information storage. The same data is stored in the nucleus of each of our cells.  This is in nuclear DNA, before taking into account separate, but smaller, storage in each of the mitochondria (see below). 

A 'gig' isn't much you might say (less than $1's worth) but the actual data storage density is in excess of anything offered by our present electronic technology.  Cells are a lot smaller than the chip in a memory stick - there around a billion cells per cubic centimetre in hard tissue.

This also points to another reality.  Had not this replication chemistry been available, and the conditions for the reactions been just right, life could not have occurred in its earthly form. 

Life relying on another replication method that was say binary would be at a disadvantage and would have to use different replication mechanisms.  If there was a chemistry, at different temperatures and chemical concentrations, allowing say six base pairs it would be different again.  We and our cousins (the other animals, plants and other organisms) that are all descended from the original replicating cell (LUCA - see above) are here because the conditions on Earth were and are just right for our kind of life to prosper.

Elsewhere in the universe it may be different.

 


Gene Mapping

Genes are just patterns of chemical molecules that are held within the replicating DNA mechanism.  The way they are encoded onto DNA can be likened to any other mechanism for copying and recording data: a DVD or even a vinyl record or the memory in this computer.  As a result they can be altered or damaged from time to time and some of these variations are successfully copied into subsequent offspring.  If they are particularly advantageous to survival and reproduction these changes, or mutations, rapidly spread throughout the species, so that over tens of thousands of years, individuals successful in one environmental niche are so different from those successful in another that a new species has formed (followed by a new genus, family, order, and so on). 

This process of periodic differentiation has been likened to the branching of a tree but because of the activity of bacteria and viruses and residual DNA that may be reactivated as well as limited cross-species reproduction  (for example Humans and Neanderthal) it is no longer believed to be quite that simple.

DNA encodes the instructions for creating each cellular colony, defining each species, and each individual within a species. DNA changes over time in such away that each change is a development on previous generations. So it is possible to trace DNA ancestry back through generations of a particular species over time.  For example, DNA studies are increasingly shedding light on the questions around human origins. 

Most animals, including humans, carry two types of DNA.  Our main genome is carried by the chromosomes in the nucleus of each of our cells. This comes from both our parents. The secondary genome, mtDNA, is carried by bacteria-like organelles within each of our cells, that convert sugars for cell energy, called mitochondria. These are all cloned (reproduced by asexual division) from the mitochondria that were within the original egg cell provided by our mother.

Cells may contain from one mitochondrion to several thousand mitochondria depending on species and cell differentiation.  As a result this is the predominant DNA found in a cellular sample.

So our mtDNA comes only from our mother; in turn from her mother; and so on and mtDNA allows us to map the female ancestral line.  This original egg cell was fertilised by a sperm from our father (sperm do not contribute their mitochondria). Once fertilised, the egg cell then divided repeatedly, differentiating in accordance with the coding instructions in our DNA, into the many cells that form the cellular colony that became 'us'.

Males are differentiated from females by a Y chromosome in place of one X. So sons can only inherit this from their father (like their family name in our culture) and periodic mutations in the DNA of the Y chromosome allow the (actual) male ancestral line to be traced back.

As a result of this work we now know that humans on the planet are all descended from a single group that left Africa less than 70 thousand years ago. 

Recent DNA analysis shows that early humans sometimes interbred with the Neanderthal; a separate hominid subspecies that left Africa much earlier and settled in the Middle East and Europe over quarter of a million years ago.

It's amazing to think that we have only understood it within my lifetime. Now the ancient view that people grow from a seed, provided by their father, and gain the spark of life at 'conception' from a god is totally debunked. So throw away all those ancient texts.

 


Viruses

Viruses have been around since life began but they are 'of life', they are not technically 'alive' because they cannot themselves reproduce. They are extremely small - about 70 microns in diametre - and until the invention of electron microscopes in the 1930's their existance had only been inferred. 

To create copies of themselves they need a host cell with the necessary reproductive mechanisms. Over the millennia viruses have evolved the necessary mechanisms to penetrate cells, much like spermatozoa, and inject their DNA or RNA and capture the host's replication mechanisms so that the infected cell begins manufacturing thousands of virion (virus particle) clones of the invader. These then capture other nearby cells in the host animal or plant; or in similar bacteria.  Huge numbers of infected cells are usually destroyed in the process, sometimes killing the plant or animal.

 

Coronavirus particles (yellow) on the surface of a dying cell (that produced them)
Niaid/National Institutes of Health/Science Photo Library (from 
https://www.newscientist.com)

 

But animals plants and bacteria have become familiar with this threat and have in turn evolved means of dealing with or living with viruses to the extent that some are exploited for the benefit of the host.

In turn viruses evolve new strategies to perpetuate their reproduction. Thus new viruses arise from time to time, sometimes jumping from one species to another when an opportunity arises.

Many animals, including humans, have an immune system that has a memory of harmful viruses and means of neutralising them. Thus, once the animal has been infected and survived, the chances of reinfection are reduced.  Vaccines work by presenting our immune system with a harmless sample that allows it to recognise a particular harmful virus.

Since I first wrote this article the World has suffered a new viral pandemic.  It is a novel corona virus for which we have no established immunity and there is no vaccine.  At the end of June 2020 the Covi-19 virus has already killed half a million people.

It is estimated that this virus will no longer find sufficient vulnerable hosts to spread further after infecting around 70% of the populations in which it is spreading.  It has a case fatality rate of just under 1%, that is, of those who catch it just under one in a hundred die.  

Quarantine restrictions are in place in many countries to protect relatively uninfected areas, with local measures to eliminate 'hot spots'.  But the majority of the world's population, in excess of five billion, are in countries in which it is presently spreading.

Unless a vaccine is available soon it seems inevitable that many millions more will be killed.  The economic consequences are also dire.

 

 

 

 


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