Monday, 25 February 2013

Towards a Cosmogenic Evolutionary Paradigm

Genesis of a new Theory of Life on Earth

Evolution from Space

The last five centuries witnessed two momentus ideas - the suggestion by Copernicus that the Earth is not the center of the universe, and the suggestion byDarwin that man is not the center of creation. Both these insights are correct, and both were resisted; in fact the great discovery of Darwin is still resisted by many conservative religionists, terrified that without the assurance that every word and letter of their bible is infallible truth, their whole edifice of faith might crumble (and conveniently ignoring many discrepancies in the text of the Bible itself, as for example between the accounts by different Gospel authors)
The Cosmogenic paradigm presents a further observation of the proper perspective of our place in the universe; one that is at the same time very new, quite old, and based on the spirit of the Copernican and Darwinian revolution.

Origin of an Idea

But first, a word at how I arrived at the conclusion I will present here. I have spent many years studying esotericism. I have also spent many years studying Palaeos pagethe history of life on Earth. I also tried for years, for two decades, to integrate the two. I looked carefully at the arguments of creationists to see if there was anything useful under the fundamentalism (there wasn't). Following something Trevor Ravenscroft says in his marvelous book The Spear of Destiny, I explored the concept of a "time organism" - of phylogenetic lineage as a single entity extended through time. Connected that with stuff that philosopher Henri Bergson says. I think there may (or may not) be something in it, but it didnt give me any further useful ideas. I looked at all sorts of syntheses. Sri Aurobindo and TeilhardI found intersting as far as the big picture went, but also, despite many fascinating parallels - not innovative enough on the scale I was intersted in. The Theosophists had a few ideas, but didnt go far enough, and were caught in a sort of Blavatsky fundamentalism. The Anthroposophists were a lot more imaginative, and I found many fascinating ideas in the works of Steiner and, later, Poppelbaum, whose book A New Zoology is a treasure-house of wonderful ideas, if you can get aroudn the obnoxious anthropocentric chauvanism that plagues his entire thesis, and presumably goes back to Steiner's christocentric, anthropocentric, and europocentric bias. In any case, I was stuck, and eventually I gave up the whole idea.
Then Ecognosis co-worker and co-creator Steven Guth approached me with an interesting suggestion. In a controversial and I would say seminal essay,Considering Islam, he says
"I've come to believe ideas can come from the stars...I have come to understand that Devas are also intergalactic travellers. (Deva = a conscious being with energy focuses that often attaches itself to a locations.) Devas don't travel in space ships but in thought, in consciousness. Small ones seem to flit around in space like algae spores and alighting on any planet that comes their way. On suitable planets they survive and create around themselves the things that interest them... So new life forms come into existence - consider the impossible worms that live on sulphur sprouting from volcanic fistulas deep under the earth's oceans - a life form once considered impossible and only recently discovered...

I suspect that conscious ideas and devas are arriving all the time. Some find their way into human minds. Some power the evolutionary processes. Some create machines or bodies for themselves out of the materials of the earth, accumulating earth elements into shapes to fit their needs - like sea animals making their shells....
Well it took me a bit of time to figure what this was all about, but in a series of email correspondences I fnally got it. And my ventures into anthroposophical thinking came in useful. Here then is a new theory of the history of life on Earth.

Earth as an Open System

Central to Steven's thesis is the observation that the Earth is an open system. To quote from the same essay.
In the 1950's I believed that the earth was watched over by a benevolent father spirit who, on prayerful request, would send down angels to help us cope with the devils that entered our lives from the underworld.

Since then I have come to learn that the earth is a open system attached to a sun that in turn floats in the Orion arm of a galaxy that we call the milky way...all this is set into a firmament of uncountable billions of similar galaxies...

Another open system that I know about is one that I can understand. It is a child's swimming pool. Into this tiny puddle - seemingly from nowhere - arrive green slime, black algae, water beetles and assassin bugs. A whole ecosystem set into motion within a week.

I have come to accept that planet earth and swimming pools are similar open systems. Influences rain in from the stars. Astrology is an attempt to explain some of these influences. Astronomer Fred Hoyle staked his considerable reputation on the idea that viruses travelled to earth on meteorites...
The fact the Earth - like everything else in the universe - an open system (long acknowledged by science). But, apart from heretics like Hoyle, scientists still see Earth as the center of evolution. But what Cosmogenic Evolution states is that the causes of evolution come from elsewhere in the cosmos. Hopwever, in presenting this hypothesis I will depart from the position of Professor Hoyle. While his intuition may be right, I do not feel teh actual physical mechanism he presents is.

Evolution from Space is not Panspermia

Now, when talking about evolution from space, I am not here talking about panspermia. The theory of Panspermia - life from space - has been propsed a number of times, most famously by Hoyle and Wickrangasinge (in a number of books) on the one hand, and James Crick (Life Itself) on the other. Panspermia says that life is so complex that it had to be seeded from elsewhere than on this Earth (either deliberately by some advanced extraterrstrial intelligence, or naturally via comets and other celestial bodies). To me this is just the God of Judeao-Christianity dressed up ina new garb. And just as one might say "if God created the universe, who created God" (if the answer is "no-one, God is self-sufficent," then I retort "then why can't the universe be self-sufficient"); we might similarily ask "if life was seeded from elsewhere, then where did that life come from. Either way you have an infinite regress.
No, I have no doubt that the chemical processes of life evolved here on this planet, whether in a primeval soup or - as has been more recently argued, in clay or deep in the Earth's crust (where it would have been shielded from the meteor bombardment suffered by the early Earth)
And I am sure life has also evolved on many other planets in the universe as well, in each case by natural processes; the result of the inherent property of nature towards more and more complex structures, as superbly described by Erich Jantsch in his masterful (and sadly out of print) work The Self-Organizing Universe.
When I speak of evolution from space then, I am not discussing or refuting the Darwinian process of natural selection, which I acknowledge as a simple fact. Rather I am referring to a metaphysical causation.

Downward and Upward Causation

Here I am inspired by my favourite philosophical worldview - emanationism - which is the foundation of such diverse and profound esoteric systems as theHeliopolis Theology of ancient Egypt; the Middle Platonism, Neopythagorianism, Hermeticism, Neoplatonism, and Gnosticism of the classical world; Taoism of China; the UpanishadsTantra, and Kashmir Shaivism of India; medieval IshraqismSufism and Kabbalah of the West and Middle East; and more recentlyTheosophyAnthroposophy, and the Western Magical Tradition. To list only a few.
Basically, what emanation says is that causation comes from above. Spirit causes matter, via a series of inetrmediary stages. Often these intermediaries are personified or described as spiritual haierarchies, angels, gods, archetypes, and so on. Interestingly, Carl Jung provides phenomonelogical evidence, and very strong arguments, for the existence of universal archetypes existing in the human psyche. I would go further than Jung and say they exist in the cosmos as a whole, and the collective unconscious merges into the cosmos, rather than being something limited to the human psyche (Jung himself often hints as much; e.g. discussions of the "psychoid archetype", synchronicity, etc).
Yet I would not discard the great insights of science either - evolution comes from below, a result of progressive self-organization.
Above and below, descent and ascent - the symbol of the overlapping triangles is a common theme, represented in the diagrams (yantras) of Tantra, the teachings of Max Theon and Sri Aurobindo, and in Judaism as the "Star of David", as well as being an oft-used symbol in the Hermetic Order of the Golden Dawn.
So what are the implications of this as regards evolution?
Well, basically it completes the understanding. We already have evolution from below, the progressive appearance of new forms, and even of whole new qualities; but we don't yet have a paradigm for the descent of higher forces. What are these higher forces anyway?
Well, Rudolph Steiner spoke of spiritual hierarchies, whilst Sri Aurobindo preferred to describe things in terms of avatars. Each new attainment was the result of an evolutionary avatar
Both these approaches are useful, despite being non-verifiable by science. But Ecognosis is not science, even though it incorporates science. What we are striving for here is an integral and all-encommpassing vision of reality.

What Science tells us - The succession of life

When we look at the history of life on Earth, we see that it is not gradual and continuous, but discrete, consisting of successive and quite distinct dynasties of life. The great 19th century French paleontolgist Cuvier was so struck by this that he considered that God had made a number of successive creations, destroying each one in turn, and the biblical Genesis and story of Adam and Eve and so on only refers to the most recent. This idea was actually quite popular, until being supplanted by Darwin's more scientific hypothesis. We know now that mass extinctions are not total, and that many species do survive. However, the feeling of distinct empires or dynasties or communities or biotic assemblages cannot be avoided.
If we consider microbes, marine invertebrates, vertebrates and some marine invertebrates, and land plants, we have four distinct series of the history of life, each made up of a serioes of seperate dynasties or biota.
For microorganisms it is
  1. Archean Era - anaerobic microbes (archaea, along with photosynthetic bacteria and some other prokaryotes)
  2. Early Proterozoic Era - aerobic microbes (photosynthetic bacteria, other bacteria) all prokaryotes
  3. Late Proterozoic Era to Recent - eukaryotes (algae and protozoa) along with prokaryotes
These stages are related solely to the absence or presence of free oxygen. A prokaryote is a prokaropte, there is not much in the way of anything characteristic there. Eukaryotes (more complex microbes) are more intersting, but thes only appear much later (since they require a lot of oxygen for their metabolism)
For marine invertebrates things are a lot more intersting. here we have
  1. Vendian Biota - latest Proterozoic
  2. Tommotian Biota - early Cambrian
  3. Cambrian Biota - later early to late Cambrian
  4. Paleozoic Biota - Ordovician to Permian periods
  5. Modern Biota - Mesozoic and Cenozoic
These are each very different. The Vendian organisms may not even be animals! The Tommotian biota includes enigmatic "chain mail" animals that seem to have been the ancestors of modern phyla. The Cambrian animals included both the earliest representatives of many modern classes and phyla, and extinct forms liketrilobitesanomalocarids, primitive brachiopods, and many other types of sea animal. Paleozoic biota significantly don't include many of the earlier Cambrian experiments (even though the Cambrian is a part of the Paleozoic era), but rather the diverse Ordovician to Permian forms, including many types ofbrachiopodstrilobitescrinoidsnautiloids, and more. Note that modern invertebrates (e.g. modern coralsgastropodsbryozoa etc) mostly appear in the earlyMesozoic, and lived alongside the great dinosaurs for about 150 million years, continuing into the Cenozoic with only minimal disruption, even though all the major terrestrial and marine vertebrates had been wiped out by the famous K-T (end Cretacoeus) extinction event.
Like the above Invertebrates, terrestrial Vertebrates (and some marine invertebrates, e.g. ammonoid cephalopods, that filled vertebrate (fish) like roles in the sea) have a similarily very distinct series of biotas. These can be grouped into a number of "mega dynasties", each of which can be subdiveded into shorter dynasties (the same goes for the marine invertebrates above). These are:
  1. Amphibian - Early Reptile (Labyrinthodont - Lepidospondyl - Pelycosaur and early Anapsid) megadynasty - Devonian through to Early Permian
  2. Therapsid (mammal-like reptile) megadynasty - Middle and Late Permian
  3. Archosaur (including dinosaurs) and marine reptiles megadynasty - Mesozoic era
  4. Mammal (and bird) megadynasty - Cenozoic era
This is the one that is best known to everyone. Who can avoid having their imagination stirred by the saga of the succession of crawling amphibians and reptiles, great dinosaurs, and mammals of past and present?
Interestingly, land plants show a different pattern again.
  1. small spore-bearing plants (rhyniophytesearly lycopodstrimerophyts, etc) - Siluro-Devonian
  2. The first forests, seed-bearing plants, giant lycopods and horsetails (sphenopsida), ferns of all sizes, the mighty coal forests - latest Devonian to Mid Permian
  3. Conifersseed-fernsginkgoscycads, the extinct Bennettitales and Cheirolepidiaceae - Mid Permian to Late Cretaceous
  4. Flowering plants - Middle Cretaceous to Recent
Note that the transition of plant megadynasties does not mach the transition of animal megadynasties. For plants the big transitions were in the mid Permian and the mid Cretaceous - several tens of millions of years earluer than the corresponding animal transitions
The above lists are not exaustive of all the sucessions of life. One could add further sequences for fish and for insects. As always, there is some overlap, but also differences. e.g. wingless insects date back to the early Devonian, but flying insects appeared suddenly in large numbers only many millions of years later, in the middle Carboniferous. Fish went through several revisions - strange early armoured forms (Wikipedia link ostracodermsplacoderms) of the Silurian and Devonian, the age of Sharks in the Carboniferous, heavy ganoid-scaled types of the Triassic through to mid Cretaceous, and modern teleost fish in the late Cretaceous, at the same time as flowering plants. One can understand polinating insects co-evolving with floering plants in the mid and late Cretaceous, but why teleost fish?

Theosophical and Anthroposophical attempts at synthesis

We have seen that Cuvier suggested a number of successive creations that preceeded the biblical Genesis. Something similar was suggested by Poppelbaum, who associated different stages of life on Earth with the different eras of Steiner's cosmology. The sequence is:

still under construction

to be inserted

This matching of geological periods with theosophical and anthroposophical root-races is a popular one with devottees of these systems, who seek to find scientific conformation for their baroque systems. Unfortuantely, both theosophy and anthroposphy are much too rigid and limited to be easily adaptable. We have seen that ther are many successive dynasties of life. So it doesnt work to fit it all in a procrustean bed. Moreover, the timescales are much too short; the Theosophistst wishing to retain the Vicrtorian estimation of ages used by Blavastky (who would surely have used modern dates if she had been around now!), the Anthroposphists in a worse position because of Steiner's ridiciously short chronology, a dating that is comparable to "young earth" creationism in its claustophobic briefness. One wonders at the fear of deep time among these people, certainly it is a challange for some earthy and sensation-orientated people to envisage millions of years of planetary and cosmic history. But without an understanding of deep time one cannot understand the great age of the universe, just as without a sense of interstellar distance one cannot grasp the great expanses of thousands or millions of light years that measure the size of the universe and its galaxies

Cosmic Devas and the Succession of Terrestrial Life

Instead of trying to match stages of earth history and life on Earth with completely unrelated esoteric formulations, I would suggest rather approaching these stages and looking at them free of prejudice. Ironically, Poppelbaum continually exhorts us to do this in understanding the animal kingdom, even though he - like all anthroposophists - fails to break free of his own mindset. Yet I was fascinated by this suggestion, which seems inherent in Goethean science. And indee dit is perhaps much better that we turn to Goethe rather than to a later interpreter like Steiner.
Poppelbaum indicates that one should view a complete animal species the way one would a human individual. He implies an animal doesnt have an individuality; only the species has. To me this is silly, because I know an individual cat or dog is just as individual as any human. The Adyar Theosophical and Anthroposophical idea of group-souls that inspires his sentiment doesn't work for me.
Yet what if we look at each of the dynasties and megadynasties of life as an individual? Not an individual in the sense of a human or animal individual, but a sort of god, a cosmic deva or daimon. Remember what Steven says about Devas coming from deep space and manifesting in different forms - e.g. life-forms and ecologies - on Earth. If we look at the story of life, we see that each empire and dynasty is actually a deva, a god, the embodiment of an archetype.
This is why each wave of life-forms is so distinct, it is a different god that comes and embodies in each in turn. We are looking at a succesion of personalities

Evolution is not ascent

There is a popular opinion that evolution is the same as ascent from lower to higher life-form; emergence from the swamp, evolution from slime to man and beyond man to god, or the popular image of the sequence from ape to modern man that so infuriates creationist religious fundamentalists, who are sochauvinistic as to be insulted at the thought that they evolved from apes (and looking at the claustrophobic worldviews and sloppy science used by the creationists, I have to sympathise with T. H. Huxley who would rather an ape for a grandfather).
Ascent of Man - a parable of evolution
Drawing by A. Busetto from Circa...
reproduced with permission of IBACNRegione Emilia-Romagna, Italy
Evolution as ascent is really the temporalisation of the great chain of being, which was pretty much how Jean-Baptiste Lqamarke saw evolution as working. But according to Darwin and to modern darwinism it is not like this at all.
An aside: Darwin, incidentally, never used the word "evolution", which means literally unrolling, as in the unrolling of a fern frond and was used to as a standard term by the anti-evolutionist preformationist camp (who said that the sperm cell actually contains a minature homunculus, and that in turn has sperm cells with even smaller homunculii in them, so that the entire history of humanity was already pre-existing in Adam!). An interesting theory, perhaps more plausably presented in the Indian Samkhya system, where all the tattwas (evolutes) are explained as pre-existing in the origional mula-prakriti, requiring only the proximity of purusha to disturn the equilibrium and set evolution in process. Whatever it's cosmic or metaphysical validity (and every myth and theory has some validity on some level) this is not the way physical evolution works.
As explained by darwinian science, evolution simply means that in a particular environment certain qualities are favoured over others. There is no ascent as such.
Even so, old paradigms die hard. For even intelligent people, the brainless dinosaurs were a sideline on the evolutionary ladder. Says an esotericist physics friend of mine in an email:
do believe in the indestructibility of all life - but the existence of, say, dinos (70+ million years of dumb life and gone for good) makes me ponder.
And paleontologist Bob Bakker, rejecting the dinosaurs as inferior position, does so not by showing that all life is at the same qualitative level, but by raising dinosaurs to the same level as mammals (so the great evolutionary ascent was not between dinosaurs and mammals but between early reptiles and dinosaurs).
The concept of devic succession actually fits in well with the otherwise materialistic approach of no qualitative ascent. No space deva is of a higher grade than any other, so the biotic dynasties they manifest are of no higher or lower grade either.
So I don't see the dinosaurs either as evolutionary mistakes or (as dinophiles do) as a glorious epiphany. They were just the embodiment of one more cosmodevic personality that happened to embody on Earth. This persionality did certainly hang around a lot longer than most of the others - 180 million years of Mesozoic time is a long time in anyone's book. Considereing higher (metazoan) life has only been around on Earth for about 540 million years, that is fully one third of the Phanerozoic eon! So perhaps that particular cosmodeva liked things here on Earth, and stayed a bit longer than the others. But eventually it decided to leave, although it has left behind an incredible heritage of fascination in the spectacle of dinosaurian forms and their fossil remains.
What I am saying then is that if we look with unbiased eyes at the series of megadynasties, as, say, amphibians, early reptiles, therapsids, archosaurs-dinosaurs, and mammals, we do not see the cliche'd ascent from the primordial swamp imagined by Victorian writers. Rather we see a distinctive personality exporessing itself in unique and spectacular forms, each form and biota having its own virtue and magnificence, regardless of whatever preconceptions we may put on it.

Megadynasties and Subdynasties

Each of the megadynasties are divided into sub-dynasties, so that for example the Amphibian - Early Reptile dynasty is divided into several earlier Amphibian (Labyrinthodont and Lepidospondyl) dynasties (Devonian through to late Carboniferous) and a more reptilian dominated (Pelycosaur and early Anapsid) dynasty (latest Carboniferous and Early Permian). These subdynasties seem to representa different development to that of the primary megadynasties.

Asteroid impacts in themselves do not cause mass extinctions

But how does the idea of gods behind biotas square with the mass extinction thing; the suggestion that, for example, the dinosaurs were wiped out by a big meteorite or asteroid?
In contrast to this Steven said in an email to me (27 November 2001)
I don't think you need to suppouse an metorite callamity to end a species line. Boredom by the presiding entity could be enough. Like those explorers in space stories; we have done all we can here lets move onto the next planet in the cosmos. Maybe we as a human race as are trying to do that - "we have stuffed up here its time to find a new spot for the human higher self to incarnate into."
So when the god gets bored it leaves, and the biota, without a higher principle to sustain and nurture it, dies out.
Amazingly, this explanation fits in perfectly. The dinosaurs were in trouble for a few million years before the asteroid hit. They had been declining all through theMaastrichtian epoch (maximum diversity was actually about 10 million years before the extinction). It is not generally known that the dinosaurs had survived at least four other big mass-extinctions - the end Carnian (early late Triassic - a big one that killed many other types of large terrestrial animals - like the very succesful ox-sized Kanneymeriid and large sheep-sized Traversodontid herbivores, as well as several marine reptile families and invertebrate species), the Rhaetan (latest Triassic, that wiped out the thecodonts and more marine reptiles and invertebrates), the Toarcian (latest early Jurassic, several types of dinosaurs and other terrestrial animals, more marine reptiles and invertebrates), the Kimmeridgean or Tithonian (end Jurassic), and the Cenomonian-Turonian (mid Cretaceous). Each time the dinosaurs had a few losses, but they continued on quite happily, and new dinosaurs evolved to replace the ones that had died out. Why did such succesful animals, that had dominated the Earth for 150 million years, and survived the small Cretaceous ice age and were able to flourish in polar conditions (like mid Cretaceous Australia), had coped with the evolution of new flowering plants, had taken everything in their stride, stop adapting to new environments?
The end of the dinosaurs was also the end of the Dinosaurian megadynasty. If we go back further, to the replacement of the Therapsid Megadynasty by the Dinosaurian one, we find that this lasted not ten million, but some 25 million years. Whilst the huge end Permian mass extinction did indeed kill off many life forms, it did not actually eliminate the therapsids (the mammal-like reptiles or proto-mammals as they are also called). But gradually, through the early andmiddle Triassic, until the end of the Carnian age, the various therapsid lineages duissaoeared one by one - first the large carnivores (Cynognathidae), then the medium carnivores and large herbivores. Finally only the small rodent-like tritylodonts and the shrew like ictodosaurian mammal-ancestors remained, and these small creatures were no rival to the dinosaurs. All this is shown in dramatic form by the following illustration by Dr Bob Bakker
The Triassic Takeover
Here we see carnivores on the left, herbivores on the right. Archosaurs (including dinosaurs) in black, therapsids in white. As with the megadynasty diagram, time is shown moving from the bottom to the top, representing both the geological column (oldest strata laid down first) and the tree of life.
In the paleontological world there are two explanations offered to explain this gradual succession of one major biotic type by another. Dr Bakker suggests that the early archosaurs and their dinosaur descendents simply were superior life-forms, they merely pushed their therapsid predecessors aside. This is very much a minority view, supporting his "hot blooded dinosaur" theory. Dr Mike Benton gives the commonly preferred explanation that the climate during much of the Triassic was very hot and arid across much of the then supercontinent of Pangea, and these desert-like conditions simply favoured animals with a reptilian metabolism (which do not require as much water or food) over the mammal-like therapsids.
Actually I find problems with both explanations. As far as Dr Bakker's thesis goes, the fact is that the early archosaurs were very different from their therapsid contemporaries; they had very different life-styles and certainly were not ecological competitors. e.g. the large crocodile-like Erythrosuchus (reptile - archosaur) certainly did not compete with the large squat wolverine-like Cynognathus (therapsid), although they undoubtedly on occaison went after the same prey, just as lions and crocodiles do in the African Serengati today.
Conversely, to say that mammals can not hold their own against reptiles in desert conditions is just nonsense - in almost all the desert conditions of the Earth today and throughout the Cenozoic the dominant animals - including the dominant carnivors - are always mammals. The only exception being PleistoceneAustralia, where marsupial carnivores did not evolve to very large size, and the top carnivore was a giant goanna (Megalania). Curiously, the same thing happened in marsupial-dominated South America during the Tertiary period, where the largest preditor was a type of giant flesh-eating bird (external link Phorusrhacid). Morphologically similar but unrelated giant carnivorous birds (DromornisBullockornis, etc) also lived in Australia throughout the Tertiary and Pleistocene.
In all probability the long decline of the Therapsids was due to a combination of several physical factors. But from an cosmogenic perspective - and jumping here from science to esotericism - we could say that the larger god that expressed itself as the Permian therapsid flowering withdrew to elsewhere in the universe, and while these evolutionary lineages still were established as local terrestrial devic impulses they were able to continue, although with lesser efficency, and eventually they just disappeared.

Minaturisation and Renewal

There is another interesting side-line to this. In both cases while the main evolutionary lineage disappeared, a smaller (tiny in relation to its large or giant ancestors) transmutated form continued and later inhereited the Earth. From the big therapsids the culmination was a tiny shrew like mammal much smaller than a mouse. From the mighty dinosaurs it was the pigeon-sized Archaeopteryx (who had even smaller and more bird-like descendents during the earliest Cretacous). Were these the seeds of transmutation planted by the space gods before their departure. Does each new evolutionary radiation have to go through a minaturisation phase?
The above illustration by Dr Bakker shows the way this works. Phylogenetically it is a sort of musical chairs - first the mammalian lineage (megadynasty II) dominates, then the archosaurian lineage (megadynasty III) takes over during the Mesozoic, and then with the extinction of the dinosaurs the mammalian lineage (megadynasty IV) comes back.
As far as the overuling god goes, these are each different personalities. It is not the case that the god of the therapsids comes back a sthe god of the mammals. It is a completely different biota. But obviously the gods use whatever mnmaterial is available.
And now, with the man-made destruction of nature, we are witnessing a new mass-extinction, and the establishment of a new biota.

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