Let us consider the following apparently definitive declaration made by the Centre for Mathematical Biology, Oxford University: “You can’t compare a living organism to a heat pump”. But … is this really true?
The more they remain the same the more they change
John Ray, the English naturalist and scientist, produced the first ever biologically-relevant definition of ‘species’. He was trying to classify plants and in 1686 wrote:
In order that an inventory of plants may be begun and a classification (divisio) of them correctly established, we must try to discover criteria of some sort for distinguishing what are called “species”. After long and considerable investigation, no surer criterion for determining species has occurred to me than the distinguishing features that perpetuate themselves in propagation from seed. Thus, no matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as to distinguish a species … Animals likewise that differ specifically preserve their distinct species permanently; one species never springs from the seed of another nor vice versa. [John Ray, 1686. Historia plantarum generalis, Tome I, Libr. I, Chap. XX, page 40. Quoted in Mayr, Ernst, 1982, The Growth of Biological Thought: Diversity, Evolution, and Inheritance, Belknap Press of Harvard University Press, Cambridge MA, p. 256. Available at: http://scienceblogs.com/evolvingthoughts/2009/05/the_first_biological_species_c.php].
Ray’s definition seems clear and simple enough … until we for example examine the herring gull, Larus argentatus, and its close cousin the lesser-black-backed gull, L. fuscus; or else the salamander Ensatina eschscholtzii and its equally close cousin E. eschscholtzii klauberi.
Can we escape evolution?
Although the word ‘constraint’ often has a negative connotation in ordinary language, it is how scientists and mathematicians operate. One of the first and most effective uses of a scientific-mathematical constraint came in the seventeenth centruy from the Frenchman Pierre de Fermat (of ‘Fermat’s last theorem’ fame). Natural philosophers of his day wondered what path light would travel on as it moved from P to R in the attached diagram. Fermat proved that light followed the ‘principle of least time’. Although the path PR looks the most direct, light does not follow it. That path requires that light spend more time travelling in the denser medium. That would increase overall journey time. In the process called ‘diffraction’, it instead follows the path PQ, and then QR. It may be the longer path, but it takes less time.
Geography and the Gibbs energy
The ‘Gibbs energy’ is invariably difficult to explain to those who don’t know what it is. And despite its importance, it was only at the end of the nineteenth century that Max Rubner, the German physicist and physiologist, at last convinced other scientists that the energy that biological organisms use in metabolic processes exactly equals the food energy they consume. Only then did scientists accept that even biological organisms obey the law of the conservation of energy. But it still required the brilliance and originality of Hans Krebs—whom many wrongly regarded as a ‘mediocre’ researcher—to unravel the important cyclic processes involved in biochemistry. His 1957 book Energy Transformations in Living Matter, written with Hans Kornberg, was the first important work to examine the thermodynamics of biochemical reactions.
Most people understand fairly easily that gravity provides a form of potential energy. It is an energy that arises due to ‘position’.
Circumambulations: what are they, and why are they relevant to biology?
So what is a circumambulation, and why is it relevant to biology and evolution?
Brian Charlesworth wrote in his book Evolution in age-structured populations (Cambridge University Press, 1994) that: “… the concept of generation time is a rather arbitrary one”. He then lists several alternatives. It is surely rather strange that something so fundamental to biology and evolution is so prone to varied interpretations. Charles Darwin said:
‘This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection’.
The difficulty, of course, is quantifying those variations, and the generations they produce, so that ‘natural selection’ can be properly measured and variations suitably quantified.
To ‘circumambulate’ is to walk around a thing. The context is often, but need not always be, sacred, such as around an altar.
“Engeny” in biology and ecology. What is it and why should we bother to measure it?
ENGENY (see definition) is how we measure Darwinian competition and evolution. It is important to correctly quantify this because as Theodosius Dobzhansky said with the title of his 1973 paper, Nothing in Biology Makes Sense Except in the Light of Evolution (March 1973 edition of American Biology Teacher).
A really big issue is, of course, how the survivors in a population respond when one amongst their number is lost. That is really what we want to quantify.
