According to Dawkins, we might be impressed by two living systems working in some sort of mutually beneficial accord but in reality it is nothing more than a convoluted extension of selfishness. Don't be too moved by the astonishing sight of a pollen dusted humming bird feeding on a symbiotic nectar rich bloom! Don't let exotic symbiotic corals (that are a union of an animal and an alga) blow your mind! Don't gloat too long over a picture of a bobtail squid packed full of symbiotic bioluminescent bacteria! Move on people, this symbiosis business is all smoke and mirrors. Life is, at heart, no more than inert bits of digital DNA code that know nothing of cooperation and harmonious coexistence but only the competitive drive to replicate. If their phenotypic expression is involved in some exquisite symbiotic arrangement or another, then this is really beside the point.
Such was the kind of paradigmatic resistance that Margulis was up against. It is probably no coincidence that it was a woman who came to the fore promoting the significance of symbiosis in the evolution of life -- and not just the symbiotic origins of mitochondria and chloroplasts or the symbiosis evinced by corals or flowering plants and their pollinators, but even the emergence of new species through the process of symbiogenesis (this is still a contentious issue -- but examples continue to emerge). Is there something deeply feminine about cooperation? Is the drive for co-existence somehow more active in the female psyche than in the male psyche? In any case, legend tells us that Margulis had a really hard time convincing her academic male superiors that certain organelles within mammalian cells were once free living bacteria. It's one thing to note the symbiotic alliance of, say, cleaner fish with their bigger fish customers (who could easily gobble up the diminutive cleaners if they wanted), but when you realise that mitochondria (the energy engines of animals) and chloroplasts (the energy engines of plants) were once separate living micro-organisms that are now symbiotically woven inside animals and plants, symbiosis emerges as a kind of advanced technique learned by life, so sophisticated and subtle in deployment that we may be blind to it. If, however, we acknowledge the important role symbiosis has played in life's evolution, the way we perceive life begins to change. Life is no longer seen to be wholly red in tooth and claw -- but rather symbiotic in embrace and interchange (at least where possible).