Arms Races, Co-Evolution and the Balance of Nature

Two things have prompted me to write some notes on these related topics. First, there are the flaws I see in the concept of the ecosystem as composed of co-evolved entities closely locked together in an arms race. Second, there is the bizarre view that the media have of nature. This is shocking since, in the case of the TV Documentaries series, I understood that their remit was public education.

An evolutionary arms race involves one or more organisms engaged in competition, each being driven by natural selection to out-adapt to the other. Good examples are the competition between predator and prey or between parasite and host  (Dawkins 1986). Each adaptation demands a reciprocal adaptation from the other, much like the arms race between tanks and anti-tank weapons. Arms races never end. To be adapted organism must constantly change. This realisation evokes the Red Queen (Carroll 1865). In the world of the Red Queen just to stay in the same place requires constant running (Van Valen 1973).There are very specific requirements for arms races in the natural world. An evolutionary arms race can only get going between living organisms and cannot involve non-living things because these cannot respond to natural selection. This is my difficulty with the concept of the ecosystem and, incidentally, with the concept of niche construction (Odling-Smee et al 2003). The ecosystem idea requires that arms races involve both living and non-living components, the latter comprising things like nest construction but also bi-products of activity such as urine and CO₂ and O₂. A limited case might be made for the former,  see (Dawkins 2004), but I fail to see how organisms and their urine, mixed with that of others, can co-evolve. Thus the view of ecosystems composed of co-evolved organisms and environment closely locked together by natural selection is deeply flawed, e.g. (Marris 2005; Marris 2009). Even in the living part of an ecosystem, species are continually invading and leaving so that any community is typically in flux (Belovsky, Botkin et al. 2004) pp.348, 349. paragraph 60. Viewing an ecosystem as composed of co-evolved species is the cause of much confusion. For this reason Richard Ladle and I suggest that the ecosystem concept be abandoned (McLachlan and Ladle 2011) p546, paragraph 2. As Dawkins puts it (Dawkins 2004) - a ecosystem is an economy, not a adaptation, so it is pointless expecting over arching co-evolutionary effects there.

This discussion leads me to a widespread fallacy much loved by the media; the idea of the Balance of Nature, which purports that everything in nature is in harmonious balance, beneficial to all (Kircher 2009). Here is an example. On a documentary film clip I viewed recently, an injured giraffe is seen being killed by lions. The explanation of the event is intriguing. It is that nature, by which is presumably meant natural selection, has in its wisdom lead to the death of the giraffe to spare it a long period of suffering. Thus both lions and giraffes benefit. Giving in to a weak ‘balance of nature’ explanation seen here diverts attention from the profound insight that can come only from a proper understanding of the arms race between lions and giraffes. The ‘balance of nature idea’ is flawed because that is not how arms races work, for reviews see (Ridley 1993), pp65-68. (Dawkins 2009), p382-390. (Dawkins 1999), p236-237. Arms races are driven by natural selection which is an impersonal force and cares not a jot for the suffering of the giraffe or any other animal, including man.

References

 Belovsky, G. E., D. B. Botkin, et al. (2004). "Ten Suggestions to Strengthen the Science of Ecology." Bioscience 54: 345-351.

         

Carroll, L. (1865). Alice's Adventures in Wonderland. London, J. M. Dent &Sons Ltd.

           

Dawkins, R. (1986). The Blind Watchmaker. Harlow, UK, Longman Scientific & Technical.

Dawkins, R. (1999). The Extended Phenotype. Oxford University Press, Second Edition.

           
Dawkins, R. (2004). A devil's chaplain. London, Phoenix.

           

Dawkins, R. (2004). "Extended Phenotype - but not too extended. A Reply to Laland, Turner and Jablonka." Biology and Philosophy 19: 377-396.

           

Dawkins, R. (2009). The Greatest Show on Earth. London, Bantam Press.

           

Kircher, J. (2009). The Ballance of Nature: Ecologies Enduring Myth. Princeton, USA., Princeton University Press.

           

Marris, E. (2005). "Shoot to kill." Nature 438: 272-273.

           

Marris, E. (2009). "The End of Invasion?" Nature 459: 327-328.

           

McLachlan, A. J. and R. Ladle (2011). "Barriers to Adaptive Reasoning in Community Ecology." Biological Reviews 86: 543-548.

Odling-Smee, F. J. , Laland, K. N. and Feldman, M. W. (2003). Princeton University Press. Princeton.  
     

Ridley, M. (1993). The Red Queen. Sex and the Evolution of Human Nature. Harmondsworth, UK, Penguine Books.

           

Van Valen, L. (1973). "A New Evolutionary Law." Evolutionary theory 1: 1-30.