The Cell Membrane: Foil for The Selfish Gene and Locus for Environmental Coupling

Cell membranes are co-extensive with the very viability of the cell. This is reflected in the fact that, apart from an outer membrane separating the cell from its external environment, the cell also has inner membranes separating its organelles from its inner and their external environment. Cell membranes function, first of all, to secure the organized molecular structures within from dispersing into the outer world. For example, “[a] hole less than 1000th  the  area of the membrane of … a red blood cell would allow its contents to escape in less than a second.” Secondly, cell membranes operate “to sustain an internal environment” compatible with cellular viability. In this connection, they are equipped with “pumps that regulate the flow of ions and molecules” into and out of the internal environments they sustain. Finally, cell membranes also “accommodate the division of the cell when it reproduces.”

Membranes are therefore vitally important to the cell. The trouble is, the intermolecular forces that hold the cell membrane together – Van der Waal’s forces – are extremely weak: they invest cell membranes with the strength of soap bubbles. Yet, life has managed to survive on Earth for nearly four billion years. Can it be expected that the environment would have maintained, for nearly four billion year!?, the narrow range of physical and chemical conditions (e.g. “temperature, salinity, acidity, redox potential, and water availability”) compatible with the soap-bubble strength of the cell membrane? This is most improbable, Lovelock argues. Further, he argues that life, primarily through the activities of bacteria, must have cooperated to adjust environmental conditions to the narrow range compatible with the indefinite survival of the cell membrane.

Lovelock’s arguments are at variance with neo-Darwinian evolutionary theory that takes the survivability of the environment as a given; and competitive self-interest as an organizing principle among species as an axiomatic necessity (see: The Bare Bones of Natural Selection). Thus, the neo-Darwinian would argue that, since there are bacteria “that can live in boiling water” and other species “that can exist in saturated brine,” surely there is no need for biotic adjustment of the environment to more favorable conditions. To this objection, Lovelock responds by pointing out that cells living in adverse conditions “are less efficient and more vulnerable than the cells of regular forms of life, and often depend for their nutrients on mainstream life.” As for cooperation among species, there is no way to effect this without foresight, intention, and communication among and between the various species, the neo-Darwinian would argue. Lovelock responds by showing how such cooperation could be achieved.

He begins by pointing out that the environment is modified by the chemistry connected with life processes. Those modifications would then have reciprocal selective effects upon life. It follows that those organisms whose life chemistry altered environmental conditions to favorable effect compatible with the integrity of the cell membrane would be selectively propagated by the environment. (These organisms would even be insulated from predation, disease, and parasitism since the reduction of their numbers by these environmental negative feedbacks would result in adverse conditions for the species effecting the negative feedbacks.) Over time, therefore, it is to be expected that the species that would be preferentially selected for propagation by the environment would be those that cooperatively altered (through division of labor exemplified by bacteria) environmental conditions to favorable effect for the cell membrane. In this way, the cell membrane, because of its literally constitutive nature, secures inter-species cooperation despite the selfish gene of the neo-Darwinians, with its axiomatically required competitive imperatives (Lovelock 1991: 95-101).

(Reference: Lovelock, James. 1991. Healing Gaia: Practical Medicine for the Planet. New York: Harmony Books)