When Kant, in 1755, published his Theory of the Heavens, his vision of evolving and emerging nebulae, he envisaged that ‘millions of years and centuries’ had been required to arrive at the present state, and saw creation as being eternal and immanent. With this, in Buffon’s words, ‘the hand of God’ was eliminated from cosmology, and the age of the universe enormously extended. ‘Men in Hooke’s time had a past of six thousand years,’ as Rossi writes, but ‘those of Kant’s times were conscious of a past of millions of years.’
Yet Kant’s millions were still very theoretical, not yet firmly grounded in geology, in any concrete knowledge of the earth. The sense of a vast geologic time filled with terrestrial events, was not to come until the next century, when Lyell, in his Principles of Geology, was able to bring into one vision both the immensity and the slowness of geologic change, forcing into consciousness a sense of older and older strata stretching back hundreds of millions of years.
Lyell’s first volume was published in 1830, and Darwin took it with him on the Beagle. Lyell’s vision of deep time was a prerequisite for Darwin’s vision too, for the almost glacially slow processes of evolution from the animals of the Cambrian to the present day required, Darwin estimated, at least 300 million years.
Stephen Jay Gould, writing about our concepts of time in Time’s Arrow, Time’s Cycle, starts by quoting Freud’s famous statement about mankind having had to endure from science ‘two great outrages upon its naive self-love’ – the Copernican and Darwinian revolutions. To these, Freud added (‘in one of history’s least modest pronouncements,’ as Gould puts it) his own revolution, the Freudian one. But he omits from his list, Gould observes, one of the greatest steps, the discovery of deep time, the needed link between the Copernican and the Darwinian revolutions. Gould speaks of our difficulty even now in ‘biting the fourth Freudian bullet,’ having any real, organic sense (beneath the conceptual or metaphoric one) of the reality of deep time. And yet this revolution, he feels, may have been the deepest of them all.
It is deep time that makes possible the blind movement of evolution, the massing and honing of minute effects over eons. It is deep time that opens a new view of nature, which if it lacks the Divine fiat, the miraculous and providential, is no less sublime in its own way. ‘There is grandeur in this view of life,’ wrote Darwin, in the famous final sentence of the Origin,
that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.
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Karl Niklas speculates on this:
One can only wonder at the lengths of the huge rhizomes that anchored Catamites to the ground. Interconnected by these subterranean roots, hundreds of Calamites trees actually made up single organisms, possibly the largest living things in Earth’s history.
When I was in Australia I saw a forest of antarctic beech said to date back to the last Ice Age, and at twenty-four thousand years old to be the oldest organism on earth. It was called a single organism because all the trees were connected, and had spread by runners and offshoots into a continuous, if many trunked and many rooted, plant fabric. Recently a monstrous underground that of fungus, Armillaria bulbosa, has been found in Michigan, covering thirty acres and weighing in excess of one hundred tons. The subterranean filaments of the Michigan that are all genetically homogeneous, and it has therefore been called the largest organism on earth.
The whole concept of what constitutes an organism or an individual becomes blurred in such instances, in a way which hardly arises in the animal kingdom (except in special cases, such as that of the colonial coral polyps), and this question has been explored by Stephen Jay Gould in Dinosaur in a Haystack.
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Though they are sometimes similar in appearance, ferns, palms, and cycads are unrelated and come from quite different plant groups. Indeed many of their ‘common’ features have evolved quite independently. Darwin was fascinated by such examples of convergent evolution, in which natural selection, acting at different times, on different forms, in different circumstances, might reach analogous ways of solving the same problem.
Even so basic a feature as wood, Niklas has stressed, has arisen independently in numerous different plant families, whenever there has been a need for a light, stiff material to support an erect tree form.
Thus tree horsetails, tree club mosses, cycads, pines, and oaks have all arrived at different mechanisms for wood formation, while tree ferns and palms, which have no true wood, have developed other ways of reinforcing themselves, using flexible but stringy stem tissue or outer roots to buttress their stems. Cycads produce a softer wood, which is not as strong, but they also reinforce their trunks with persistent leaf bases, which give them their armored appearance. Other groups, like the long-extinct Sphenophyllales, developed dense wood without ever assuming an arboreal form.
One also sees convergent evolution in the animal kingdom, with the separate evolution of eyes, for example, in many different phyla – in jellyfish, in worms, in Crustacea and insects, in scallops, and in cuttlefish and other cephalopods, as well as in vertebrates. All of these eyes are quite different in structure, as they are different in origin, and yet, they are all dependent on the operation of the same basic genes. The study of these PAX eye-coding genes, and other genes like the homeo-box genes, which determine the morphogenesis of bodies and organs, is revealing, more radically and deeply than anyone could have suspected, the fundamental unity of all life. Richard Dawkins has recently provided an excellent discussion of the development of eyes, in particular, in his book Climbing Mount Improbable.
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Sir Robert Schomburg described his great excitement on finding Victoria regia:
It was on the first of January 1837, while contending with the difficulties which, in various forms, Nature interposed to bar our progress up the Berbice River, that we reached a spot where the river expanded, and formed a currentless basin. Something on the other side of this basin attracted my attention; I could not form an idea of what it might be; but, urging the crew to increase the speed of their paddling, we presently neared the object which had roused my curiosity – and lo! a vegetable wonder! All disasters were forgotten; I was a botanist, and I felt myself rewarded. There were gigantic leaves, five to six feet across, flat, with a deep rim, light green above and vivid crimson below, floating upon the water; while in keeping with this astonishing foliage, I beheld luxuriant flowers, each composed of numerous petals, which passed in alternate tints from pure white to rose and pink.
And in the Victoria regia tank, under its giant leaves, I was later to learn, resided a strange animal, a small medusa – Craspedacusta by name. This was found in 1880 and considered to be the first-ever freshwater jellyfish (though it was subsequently realized to be the medusoid form of a hydrozoan, Limnocodium ). For many years, Craspedacusta was found only in artificial environments – tanks in botanical gardens – but is has now been found in several lakes, including Lake Fena in Guam.