Some cacti do not grow well on their own roots in our climate ,so you may graft them on a suitable host stem, taking care of some compatibility of the two species involved .The grafted plant then grows without problem but there are some changes. The structure of flowers do not change but the properties of flowering, number of flowers ,duration,…, are the characteristics of the host stem! Also the form of the grafted plant does not really change except that it may be fatter or smaller, again depending on the characteristics of the stem.
So you discover the genotype and the phenotype of a species. At first this may seem strange, not everything is dictated by the genetic structure, indeed the genetic structure of the graft remains unchanged, but some properties of the stem, not completely determined by its genetic structure, are transferred to the grafted plant. Of course grafting is not a natural phenomenon, although there are parasite plants that actually grow as “grafted” plants on their host.
I was once happy to find Hyobanche Sanguinaria on the sandy soil in Almeria, close to the university then (now covered by new buildings), this is a rather beautiful root-parasite penetrating by rhizomes the host plant underground ,but more commonly the Mistletoe is another example. Thus the phenotype is the interesting discovery in grafting, artificial or natural, the plant can change its phenotype by some remarkable process.
Another — seemingly unrelated — discovery for me was convergence ; I once noticed the uncanny resemblance between Astrophytum Asterias and a sea urchin . Later I found many other examples of Xerophytic plants shaped like sea animals or plants and finally I ended up reading some scientific papers about (natural) convergence i.e. different species, often living in entirely different environments, but developing the same shape and sometimes the resemblance was really uncanny ! I learned that these were not really “accidental” phenomena ,but the problems of living in certain environments logically found similar solutions, often based on ergonomic or purely geometric principles.
This seemed to tell me that form did not necessarily follow from accidental mutations steering the evolution, the assumed randomness of the mutations and the independence of very different species would make converging mutations on the aspect of form or shape rather unlikely .The nature of the problems posed by different environments leading to similar geometric solutions cannot steer the random mutations and natural selection could not select the same shape if it never occurred regularly among the possibilities. Among common shape-properties that appear at different places we may mention: symmetry, spiral growth and Fibonacci numbers, Lamé ovals or ovoid's in particular so-called super-shape . These shapes suggest life strives for some economic restriction on energy use (symmetry, super-shape) or some common algorithm for growing (spirals). The abundance of these shapes in completely different species suggests that they are not the result of different random mutations in the evolution of those species, doesn’t it?
Mathematicians use so-called Jones polynomials — some topological invariant in Knot Theory — to calculate the complexity of a knot .The DNA structure and its replication, the double helix, was in fact first discovered by two Cambridge mathematicians, before it was observed as the structure of DNA. The splitting of the DNA, unfolding and folding two copies again, happens too fast. So mathematicians checked the behaviour of the Jones invariant under the operation and discovered it changed, they found the DNA was cut and glued by something. The enzymes doing that were called Topoisomerases when later biologists had discovered the actual enzymes that were doing this and they kept the name referring to the topology of the knots. A mutation is thus a mistake in the cutting and the gluing, that is the fault of the Topoisomerases! But why do scientists view these changes as errors, even random errors? Do they put it behind the Topoisomerases to actually play a little and do some experiments guided by some adventurous inclination of the species? Invariance does not exist in nature so why would species” strive” for genetic invariance if variation is the common thing? The gene is not an isolated ”defender” of the species, for example we now know there are epi-genes doing some changing on short term level, and the whole “idea” behind having a genetic structure is to have adaptability to changes in the biotope as well as conservation of useful structure. The genes and the enzymes creating the next generation work in close connection, so I do not accept that they are not deeper connected in a complex system of variable genetic developments fitting in a variable environment and changing living conditions! So the genes are cooperating with other ingredients in the individuals in a species, the environment has influence via the form or shape conditioning — see convergence as mentioned above — and we also have a phenotype not completely defined by the genetic structure.
The environment or biotope is — next to the changing landscape and climate — to a large extent also determined by all living beings in it. Within a species there is competition but also cooperation, and in each biotope those behaviours also exist between different species (e.g. extreme forms of symbiosis).
Neither the competition, nor the cooperation needs to derive from natural selection, in fact competition is usually seen as an ingredient or even cause of the natural selection — so not a consequence — see survival of the fittest. Similar for cooperation in the species and more clearly so for interspecies cooperation; both competition and cooperation are “social” phenomena not really fitting in a purely biological theory. In fact those behaviours show up naturally in abstract Game Theory. Is competition supporting survival? It may create stronger organisms but cooperation may lead to peaceful solutions in using the same biotope. The fact that the human race which now dominates life on Earth has developed some altruism and care for the weak members of society and is actually now discovering the global care for life — supporting the “weaker” species — on the planet, is perhaps a proof that forming cooperating herds and developing cooperation is a good strategy for survival. The danger of extinction is inherent in the notion of competition and it is a fact that many species went extinct because of interspecies competition. Thus it is not clear why competition, but also cooperation, might be viewed as a result of natural selection. What would be the force, or urge, driving the species to cooperation?
Since epi-genes allow the manipulation of the genetic activity the whole, genetic system is driven by more complex mechanisms including the phenotype which seems to encode the intensity, quality, organization of the genetic activity as a kind of interface related to the embedding into reality, thus in the biotope. There certainly is an effect of the community of living organisms in the biotope on the development of each member which corresponds then to a deeper interior structure in the organism dealing with the interaction of the genetic structure and the exterior biotope structure ; what we call the phenotype could be an effect of this deeper structure I would call the “biotope awareness”. Philosophically speaking one could call the genetic structure the “what” and the biotope awareness the “how” of the organism’s life. The epigenetic structure and the phenotype are effects of the “how” structure and also some interspecies “communication” — root of the cohabitation strategies in a biotope, for example symbiosis —belongs there.
Organized cooperation is very obvious in growing cell structures, so at the cell level already. The biotope awareness of our cells created the complex life system we are (in fact, their biotope ), the cooperation between the cells is not depending on our brain activity, in fact it is the converse our thinking depends on the cell’s biotope awareness. The phenotype made me think of some kind of abstraction added to the concrete genetic structure, an abstraction depending on the exterior world with some “social” aspects (a.o. cooperation or competition) connected to members of the same species and even other species nearby. Our human cognitive abstract world — which could be thought of as containing our phenotype even if we cannot be grafted, yet some organs can be transplanted if our genetic system does not repel them —is also an interior-exterior interface and it could result from the primitive biotope awareness before even a complex nervous system existed.
From the philosophy of grafting to the source of human thinking…one small step for humanity!