Friday, 20 September 2013

Trying to understand Creationism

The Creation Resources Trust has seven statements of belief, 1 of which these are two:

The acts of creation described in Genesis took place a few thousand rather than millions of years ago. This means that the earth and universe are quite young, which is consistent with much scientific evidence and biblical chronology.

The great flood described in Genesis was an historic event, world-wide in its extent and its effect. Most of the earth's fossil-bearing sediments were formed during this great cataclysm.

Among Christian Creationists, there is agreement that life on Earth began approximately 6,000 years ago, whereas those who accept that evolution provides the best explanation of the diversity of living organisms propose that life began with an original single cell about 3,500,000,000 years ago. I give the numbers in full to get a better sense of the difference between the time scales of the two opposing views.

Two further statements from the Creation Resources Trust are fundamental to the views of Christian Creationists - their absolute belief in the literal truth of The Bible:

The whole Bible is the written word of God, divinely inspired and without error in its original manuscripts. Therefore all its assertions are scientifically and historically accurate, including the account of the origin of the universe, the earth and the life upon it recorded in the book of Genesis.

All the basic types ('kinds') of living things, including human beings, were created by direct acts of God during six literal days, as described in Genesis chapter 1. There was potential for wide variation within those types, but no possibility of evolution from one type to another.

Thus, The Bible, as the word of God, is absolute, so there cannot be any question as to its veracity on all points. The account of Creation in Genesis seems improbable and I am astonished to read that: “The theory of evolution, despite being widely believed and taught, has not been scientifically proven, the available evidence being overwhelmingly in favour of the biblical record of creation.” 1 Really?

I wonder what contemporary Creationists make of the account given by Philip Henry Gosse in Omphalos? 2 He is the sole Creationist that I have come to know well, although only through his writings and those of his biographers, as he died in 1888. Henry Gosse was a member of the Brethren, a believer in the literal truth of The Bible and someone who found developments in geology during the mid-Nineteenth Century to challenge his beliefs. That is why Omphalos is sub-titled an attempt to untie the geological knot. In the book, Gosse shows his excellent knowledge of geological time periods and accepts that many thousands of years were needed to produce coal seams, with many rock strata taking much longer to form. Gosse then introduces his theory of prochronic and diachronic existence to resolve the conflict between those that believe in geological time scales and those who do not. Diachronic refers to all matter and organisms that have existed since the Creation, whereas rock strata, fossils, etc. that are more than a few thousand years old, provide evidence of an existence before time - before the act of Creation. Gosse’s explanation is now rarely mentioned and the current view, as in the statement from the Creation Resources Trust, is that strata and fossils result from the Great Flood, events that would have been impossibly cataclysmic. It was a view with which Gosse would have been familiar, but was seemingly unable to accept. I have affection for Henry Gosse and know well the challenges brought by his absolute faith; 3 a faith that provided support and meaning, but made him a prisoner, unable to accept views that challenged his narrow interpretation of The Bible. It didn’t help that he was part of a small, and isolated, group of believers who reinforced each other’s restricted views.

Creationists accept that evolution occurs, 4 but only in providing small shifts resulting in varieties of organisms whose basic structure is unchanged. In a World that has existed for c 6000 years there will be many such changes, but what about changes that happened over, say, 1,000,000 years or 1,000,000,000 years? There are many varieties of domestic animals - look at the range of types of dogs, sheep or cattle, for example - and these result from selective breeding. Is it possible for Creationists to accept (theoretically, of course) that such changes can also result from natural barriers to reproduction, allowing separate and distinct populations to result?

Whether one is a Creationist or an Evolutionist, we must all accept that individual organisms are the result of genes which provide the code for an individual's structure and function and it is the genetic blueprint that is passed from one generation to the next. We must also all accept that, during the replication of genetic material, mutations occur and these may affect the biology of the organism. If mutations result in changes that make an individual more successful in its environment, it follows that these mutations are likely to be passed on to offspring and thus spread through successive generations. It is this sequence that controls the microevolution accepted by Creationists and the whole process of evolution accepted by those who see this as the mechanism whereby new types of organisms occur over long periods of time.

The main conflict between Creationists and Evolutionists is caused by religion; some Christians finding it impossible to accept that changes occur without the need for a Creator. It was this view, accepted increasingly in the Nineteenth Century, that so offended Henry Gosse. His theory of prochronic existence has now largely disappeared, and it was criticised by both the contemporary scientific and religious communities, but he still had his absolute Christian faith. There have certainly been changes of opinion among Christians over time and there are many who can accept evolution without feeling that this is a threat to their belief in Christ and His message. Of course, questioning the literal truth of The Bible then brings problems of exegesis, in that decisions need to be made about what is factual and what is metaphorical.

I am firmly in the Evolutionist camp, but I have no idea how the first cell came into existence and cannot imagine what mutations led to all the changes that resulted in the diversity of life forms that exist, or have existed. I accept my ignorance and know that I will never get answers, as I cannot understand the time scales involved and cannot comprehend all the changes that have occurred in the environment to allow the selection of mutations. I have no “truth” to defend.


2 Philip Henry Gosse (1857) Omphalos: an attempt to untie the geological knot. London, Van Voorst.

3 Roger S Wotton (2012) Walking with Gosse: Natural History, Creation and Religious Conflicts. Southampton, Clio Publishing.


Thursday, 12 September 2013

Walking on water

Some small animals walk on water, among the best known being the pond skaters that row themselves over the surface using four of their six legs. Close observation of water bodies reveals the presence of other insects like springtails, which move as though the water surface was part of their usual terrestrial habitat. As we know from childhood experiments with floating pins, water has high surface tension and this is strong enough to support light objects, including these animals.

When looking at ponds, we are sometimes surprised to see snails gliding along the surface, this time on the water side of the interface. They move using muscular contractions of the foot on a trail of mucus and this seems to work just as well at the water-air interface as it does on a solid surface and is again dependent on surface tension. The water-air interface also supports large numbers of bacteria and other single-celled organisms like amoebae and their relatives, but we need powerful microscopes to see their presence. They have also been shown to move here as though they were on a solid surface. 1

Dust, and other particles, fall on the air side of the interface and a variety of compounds accumulate on the water side, among which will be those that do not mix readily with water, like fats. These materials provide food for the bacteria found at the interface, and bacteria, in turn, are the food of the other single-celled organisms. Nutrients present also provide good conditions for the growth of algae and, as there is rarely a shortage of light for photosynthesis, algal colonies can also be found. Organic matter, both dead and living, thus forms a surface film that is very thin, but which covers about 70% of the surface of the Earth and, while in some habitats this film is rather poorly developed, in others it is sufficiently thick to produce visible slicks, sometimes thought by observers to be the result of a pollution incident. Surface films can also be blown into foams by the inclusion of bubbles and we have all seen windrows on the surface of the sea, or large lakes, after strong winds have abated.

In addition to the “permanent” residents of the surface film, other animals use this resource as food. For example, I have watched grey mullet feeding at the surface of the water in the harbour at Muros in Galicia and these fish have special adaptations of the gills that enable them to capture and concentrate fine particles. They are thus well adapted to collect the nutritious resources present in the surface film, in addition to those found elsewhere within the water column.


Perhaps the best adapted animals that feed at the water-air interface are the larvae of Anopheles mosquitoes. These insects have hydrophobic hairs on their bodies that ensure they remain attached at the surface until they break away by swimming downwards into the water of the ponds and lakes in which they live. Once anchored at the surface, the head of an Anopheles mosquito larva is rotated through 180 degrees and it then uses its mouthparts to produce a current that draws surface film material near the mouth. The larvae feed from this and surface film provides the majority of their diet, allowing rapid growth. Larval life is then followed by pupation and the emergence of adult flies, the females of which are important biting pests. Adult female Anopheles mosquitoes are the vectors of malaria, one of the most widespread lethal, and sub-lethal, diseases of humans, so the surface films on the ponds and lakes where the larvae live are important in maintaining the incidence of the disease.

In an article in the magazine BioScience, Terry Preston and I described surface films as being overlooked and that can be interpreted in several ways. 1 While their total volume makes up a miniscule fraction of the total volume of water on Earth, they are present at all interfaces between water and air and thus have an enormous total area. Surface films are ubiquitous, yet we only notice their presence when slicks or foams are present, or we see animals moving at the interface. They are also largely ignored by aquatic scientists and deserve much more attention. Perhaps that attention will come when a human achieves the impossible and walks on water without an artificial aid? After all, we are told that it has been done once before: “....when Peter was come down out of the ship, he walked on the water.....". 2

1 Roger S Wotton and Terence M Preston (2005) Surface films - areas of water bodies that are often overlooked. BioScience 55: 137-145.


Monday, 2 September 2013

Plagues of flies

I love northern Sweden. There is something about the forests, mountains and rivers that I find very attractive, with the contrast between the long days of summer and the short, very cold days of winter bringing something to the mix. However, there is a downside and that is the number of biting flies, with females that need to take a blood meal before they can mature eggs. I’ve been their target on many occasions and easily the worst was while I was collecting aquatic animals in a small stream, part of a research project in which I was involved. I knew there were mosquitoes around, but it became really bad and I had to turn up the round neck of my jumper and pull down my woolly hat so that no area of my face and neck was exposed. Despite these precautions, I still received many bites and I could hear the constant “singing” of the mosquitoes. I was very pleased to get away from there.
As Henry Gosse wrote in The Romance of Natural History,1 “One needs to spend a night among musquitoes to understand what a true plague of flies is” and, in that book, he also introduces us to the Golubacser [Golubatz] fly (which he identifies as Simulium Columbaschense [colombaschense], a blackfly). Gosse quotes the comments of a traveller (Edmund Spencer):

These singular and venomous insects, somewhat resembling musquitoes, generally make their appearance during the first great heat of the summer, in such numbers as to appear like vast volumes of smoke. Their attacks are always directed against every description of quadruped, and so potent is the poison they communicate, that even the ox is unable to withstand its influence, for he always expires in less than two hours. This results, not so much from the virulence of the poison, as that every vulnerable part is simultaneously covered with these most destructive insects; when the wretched animals, frenzied with pain, rush wild through the fields till death puts a period to their sufferings, or they accelerate dissolution by plunging headlong into the rivers.

It is worth remembering that only female blackflies bite and they inject saliva which contains anticoagulants to ensure the flow of blood. It is likely that the quadrupeds that Spencer describes were tormented by the number of bites, the shock that the mass of bites promoted, and an immune response to the insect saliva. Humans bitten by blackflies are also familiar with these reactions. The “vast volumes of smoke” may refer to the numbers of female flies, but is more likely to be a description of the mating swarms formed by the non-biting male flies to attract females.

Roger Crosskey, the authority on blackflies, describes the area of Banat on the Danube as being the principal area for these flies, that “excited much interest in the eighteenth century” 2 and that embark upon “their massive wind-assisted migrations across country - reaching southwards deep into Serbia and eastward into Romania, and sometimes killing animals 150 km and more away from the Danube.” Fortunately, both for humans and their livestock, the fast-flowing sections of the river that were the habitat for many millions of Simulium colombaschense larvae have been transformed by dam-building and the insects are no longer devastating pests. However, there are many regions of the World where major pest outbreaks of other blackflies occur, although few with the notoriety of the Golubatz fly.

Biting midges (ceratopogonids) are another group of flies that can reach pest proportions in high latitudes and their miniscule size belies their effect when attacking in numbers. Again, it is the female flies which bite, but neither male nor female flies of their relatives, the dancing midges (chironomids) and lake flies (chaoborids), need to take a blood meal, although many people are not convinced of the fact. Both types of flies are found in staggering numbers in some locations.

Lake Myvatn (Myvatn = midge lake) in Iceland is rich in algal nutrients and is thus highly productive. Dancing midge larvae take advantage of the abundant food (algae + algal and microbial by-products) and grow in astonishing numbers before pupating and then swimming to the surface of the lake, where they emerge as adults and begin flying. There are so many of them 3 that domestic animals are provided with shelters in which to escape the torment of being surrounded by the flies and the dangerous risk of inhaling them. Although the flies do not bite, males form smoke-like swarms to attract females, just like the blackflies in Gosse’s quote, and livestock may provide suitable swarming marker sites, as there are no trees.

Lake flies may also be found in huge numbers, forming clouds of insects over Lake Victoria, for example. 4 The larvae of these insects feed on plankton in the surface waters and, just like the dancing midge larvae of Myvatn, they transform to pupae that swim to the surface to allow emergence of the adults. Such large numbers of flies occur that they are collected by villagers around the margins of the lake and made into “Kungu cakes” that are piled on market stalls and provide a good source of protein - flies carried by winds may also be the source of manna (as described in The Bible). 5 The cast skins of the pupae, just like those of dancing midges, are washed ashore and these provide fertiliser, as do the millions of dead insect bodies, including those of females that have laid their eggs into the water to complete the life cycle.

Dense swarms of blackflies, biting midges, dancing midges and lake flies are natural, but it would be surprising if mythologies did not develop about their significance and that a divine force was responsible for their extraordinary quantities. In some years, conditions are such that even larger numbers of flies are produced than usual and this can result in the idea of plagues that are somehow sent to punish because of their adverse effects. The 10 Plagues of Egypt are among the most well-known of these types of events, with dancing midges, blackflies and mosquitoes likely to be the source of three of the Plagues, occurring because of unusual climatic events over a short time period.6 We humans love to explain impressive natural phenomena in terms of the supernatural, when we should really be in awe of the evolutionary processes that have resulted in the successful exploitation of resources. However, we seem to prefer being imaginative rather than rational and “plagues” threaten our sense of control over the Natural World.

1 Philip Henry Gosse (1860) The Romance of Natural History. London, J. Nisbet and Co.
2 Roger W. Crosskey (1990) The Natural History of Blackflies. Chichester, John Wiley.