by Keith Morrison
©2007 Keith Morrison
- And Deity said, Let biochemistry bring forth abundantly the moving creatures that hath life, and vegetation that hath life and isnt moving quite so much.
And Deity watched every living creature that moveth (and vegetation which moveth not quite so much), which the waters brought forth abundantly, after their kind, taking into account genetic drift and speciation which leadeth to new kinds. And Deity saw that it was good.
And Deity blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let microorganisms multiply in the earth and symbiotically and parasitically within other things.
And Deity said, Let evolution bring forth the living creature after his ancestral species, cattle, and creeping thing, and beast of the earth. And it was so.
And the next time Deity looked, the world had been struck by a mighty ball of frozen volatiles and rock. And many of the living creatures and the vegetation; yea, even unto the microorganisms; had had a pretty bad time of it.
And Deity, sore vexed, looked down, saying, Damn it! Who sent that brown dwarf through the Oort Cloud?
- The Book of Norso-mri, Chapter 1
When last we left Gayajan (and I have to renege on a promise; no maps, as getting married sort of took up a bit of my time), it had been 20 million years since a relatively minor mass extinction.
What does a mass extinction mean to the biosphere?
Firstly, two types of organisms are affected more than others by a mass extinction event. The first, if the extinction is caused by an event whose temporal and physical limits are well-definedsay, a large meteor impact or volcanic activityare obviously those species that arent very widespread and happen to be living in the affected area. For instance, if there was a moderately large impact in Central Africa, we could say buh-bye to the gorillas, chimps and bonobos. Its pure bad luck.
The second type that tends to not do so well is the specialist. Which leads into the next question: Whats the difference between a specialist organism and a generalist?
Answers vary depending on who you ask, but a generally accepted definition is that a specialist organism is one that depends exclusively on another specific type of organism or even a specific species, or a specific environment, as a critical part of their survival. Generalists dont. Now, that isnt a black-and-white difference, of course. The natural world rarely is. Some species are more specialist than others; some more generalist than others.
Well use bears as an example. Polar bears evolved fairly recently (within the last two million years or so), and are among the most specialized of bears. They are obligate carnivores (although their teeth arent quite there yet), and their physiology, from hair to insulation, as well as behaviour and food choice, is specialized for living in the Arctic. Take away the ice in a short period of time, and polar bears likely go extinct.
Polar bears evolved from grizzlies (brown bears), and are still close enough relations that they have successfully interbred in the wild. Grizzlies are more generalists, able to survive on both plants and animalsnot to mention a wider range of animalsand have a wider range of environments they can thrive in. North American black bears are even greater generalists, being more widespread than the grizzlies, which has allowed them a better time of making it since humans showed up to compete and sometimes directly prey on bears.
If the environment is stable, specialists can really shine. Being a specialist means youre more efficient at what you do, or youve got the uniquely required tools to exploit a niche that no other species can touch. Koalas eat eucalyptus; few other animals can, due to the toxicity of the leaves. Polar bears have the skills and equipment to exploit an arctic environment that their ancestors the browns, or cousins the black bears, cannot. The longer an environment is stable, the more specialization is likely to occur across the biosphere in all sorts of organisms, often creating complex chains of interdependence. Plant A has flowers that are most attractive to Insect B, so it depends on Insect B for its pollenization, while As nectar is the only thing Insect B can eat. Bird C nests only on Plant A and specializes in hunting Rodent D, a generalist eater; this keeps Rodent Ds population in check, which stops the rodent from eating up Plant A (among others) and Insect B.
Again, thats when the environment is stable. And when the environment is in the middle of a rapid change? Well, during periods of change, it often truly sucks to be a specialist. Either a necessary part of your environment is no longer as useful, or, in the case of specialist eaters, theres a good chance your food is going to sufferwhich means youre going to suffer. Koalas are an excellent example of the latter. If eucalyptus trees take a hit for whatever reason, koalas are in a great deal of trouble.
Using my preceding hypothetical example, lets suppose something happens to Plant A. In that case, Insect B and Bird C are out of home and lunch, which allows Rodent D to increase population, further reducing Plant A and Insect B and feeding back into the cycle. If something happens to Insect B, Plant A doesnt get adequate pollenization; this reduces the population of Plant A, with the subsequent effects on the bird and the rodent. If something happens to Bird C, the rodent eats more of the plant and the insect, which in turn means the plant is screwed, and so on and so forth, in a vicious circle of positive feedback.
The only one who can get away reasonably okay is the rodent. While it may have eaten up Plant A and Insect B, it doesnt depend on them. It can move on to other plants and insects, and without Bird B around, individual rodents have a greater chance of surviving without being eaten.
Note: The rodent has a greater chance of surviving, not an ironclad guarantee. If the insect and plant have been so successful theres nothing else in the local environment, even the rodent could be in for some hard times. So depending on the situation, the rodent might just bite the big one as well, thus explaining why even generalists can take hits in extinction events. Natural cycles, such as the boom and bust cycles common in Arctic animals (or any environments where food chains are short and limited), are an example of how populations of predator and prey fluctuate. An extinction event is when the bust goes a bit too far.
After an extinction event, generalists usually flourish and diversify. often having descendants who themselves specialize and occupy some of the recently vacated niches. Mammals are perhaps the classic example most schoolchildren are familiar with. Although not everything was a tiny shrew-like animal during the Cretaceousmammals having diversified already to a greater extant than thatthe large herbivorous and carnivorous land animal and large marine animal niches were quite obviously filled.
When the dinosaurs and marine reptiles visited the Great Jurassic Park in the Sky, mammals had their chance to shine (well, excepting a brief period during the Eocene when flightless birds were the dominant land predator until the overgrown turkeys were put in their place).
Incidentally, the mammal/dinosaur exchange is interesting in itself if you go back a bit further. In the Permian, had people been around to look at the landscape, you would have predicted the mammals would be the dominant land animals. The mammal-like reptiles, such as the sail-backed animals people confuse with dinosaurs, were the dominant predators; and even after the great Permian Extinction (90% of all life dead, yadda yadda), the synapsids were among the first to recover in the large animal niche, to the point where one genus, Lystrosaurus, a largish herbivore, became the most widespread large land animal in the planets history. No other single species, before or since, including our own, has made up such dominant percentage of animal life on land. Dinosaurs, at that point, were small reptiles that wouldnt look out of place as a pet in a big aquarium.
So what happened?
In the last few years its been recognized that at the end of the Permian and into the Triassic, oxygen levels in the atmosphere plummeted. By the end of the Triassic, another mass extinction, the O2 levels were running at 11 to 12%, roughly equivalent to what youd experience in the mountains at 14,000 feet. For the last 205 million years its been rising, was highest in the Eocene (23%), probably a result of the extensive forests that reached from one pole to the other, and dropped to the current 21%.
Also in the last few years its been recognized that (a) birds are descended from theropod dinosaurs, (b) birds have a more efficient respiratory system than mammals, and (c) dinosaur skeletons show they had that same respiratory system first.
The bird system is more efficient than mammals because its not tidalthat is, in-and-outlike our own. Mammals can only extract as much oxygen as they can in a single breath, and in land mammals the lungs cant force all the air out to get rid of all the oxygen-depleted air and take in a complete lungful of fresh air. Our lungs are a car engine with the air intake partly blocked. The engine can run, but not as well as theoretically possible. Birds, on the other hand, have a somewhat different system. They have air sacs in the body and two openings in each lung. When the bird breathes in, air flows into the bottom of the lung and the air sacs at the back of the body at the same time. The air flowing into the bottom of the lung pushes the air already there (with the oxygen extracted) into the front air sacs. When the bird breathes out, the air in the rear air sacs is pushed into the lungs from the bottom and out through the top, and the front air sacs push their stale air (which had been in the lungs on the inhale) out, joining the air forced out of the lungs.
The end result is that the air flow in the lungs is always from bottom to top, theres always fresh air coming in (either directly from the outside or from storage in the rear air sacs) and the stale air is either expelled directly from the lungs to the outside or stored in the front air sacs to be expelled in the next breath. The air pressure and oxygen content in the lungs is constant, which means that a bird, in a given period of time and at the same oxygen levels, will be able to extract more oxygen than a mammal or reptile.
The bird has a car engine that not only has the air intake wide open, it has a turbocharger to force more air in there. And dinosaurs probably had the same system. Its theorized that the primitive ancestor of the dinosaur might have been a highland-living reptile back in the Carboniferous and early Permian, evolving a way of extracting oxygen more efficiently in the thinner air. As oxygen levels crashed and other animals, like the giant arthropods that needed high O2 to survive, disappeared, the dinosaur ancestors moved down into lower areas. Their problem was that other reptiles, including the synapsids who became the mammals, were already there and therefore positioned to become dominant (and did so). The arthropods were hit first by the lowering oxygen because their respiratory systems arent as efficient as that of vertebrates.
As oxygen levels fell further, the land reptiles and synapsidswith their non-tidal lungsbecame less and less efficient. When the O2 level hit its nadir at the end of the Triassic, the dinosaurs turbocharged lungs gave them their chance to shine. While other animals were gasping for breath, they could zoom around and thrive and grow. As oxygen levels gradually increased, those turbochargers could take advantage of the increased oxygen and allow the engines to get bigger.
Really, really bigger. Like, one-hundred-tonne, thirty-five-meter-long Argentinasaurus bigger.
Eventually, oxygen levels got up to where the newly-evolved mammals could come out and play with the big boysbut by that time, the big boys werent allowing anybody in. For over a hundred million years mammals had to be satisfied with occupying small animal niches, always dominated by those damned turbocharged monsters. Even the reptiles whod been the first into the air were outcompeted by the little feathered dinosaurian upstarts who took to wing with lungs that were, by an accident of biological history, far better suited for flying faster, higher and more efficiently. The pterosaurs were on their way out long before the K-T extinction.
In the oceans, its a different story. The lifestyle there for an air-breather is more suited to the traditional mammal and reptile breathing apparatus, taking and holding your breath, and the existence of air-filled sacs tends to be counterproductive if you want to dive. The sea-going lizards never gave the dinosaurs an opening to get into their world, and mammals beat the birds into the water when those marine reptiles died out; thus, the oceans top predator niche is filled by the sperm whale and orca, rather than a gigantic killer penguin.
Even back on land, when mammals could (and did!) get bigger, they never did match the size of the sauropods or big theropod predators. Their lungs, without that turbocharged design, could not provide the efficiency needed.
Theres a point to this digression: Biological history from the Permian to the modern day, with the interplay between proto-mammal, reptile, dinosaur, mammal and bird, shows how life moves and adapts through accident and opportunity, and also how mass extinctions can have really unforeseen effects. It was historical accident that gave rise to the dinosaurs. Eyes have evolved many times in different animal lineages (thus, the eye of an insect is different from that of a vertebrate, which is different again from a squid, which is different from a clam). Flight has evolved at least four separate times (insects, pterosaurs, birds, bats). The ability to breathe air, at least twice (arthopods, vertebrates). But that turbocharged lung only showed up once. Had that long-ago lineage never arisen, either from environmental change or being eaten by a giant spider or a cousin reptile or amphibian, there wouldnt have been a set of lungs pre-adapted to deal with low oxygen levels.
The vertebrates would have made it through alright, but the proto-mammals, already present and with no competition from a fast-moving efficient competitor, would have likely risen to dominance on land. They would have gotten bigger as the oxygen levels rose, and by the Cretaceous, the scene we would have seen on land might not look that different from what wed see today. There would be large herds of furry animals, a few somewhat larger ones weighing up to a few tonnes, and predators with specialized teeth eating them. Oh, thered be differences. Grasses werent around yet, so theyd be grazing on ferns and other plants instead, but its a scene wed be familiar with.
In the air, not so much. With no competition from birds, the pterosaurs probably wouldnt have gone into decline. Bats might still evolve, but since their lung system wouldnt have been any more efficient than the pterosaurs, theyd likely not become dominant. They might end up being in a place not so different from now.
That aside, back to Gayajan. The mass extinction 20 million years before means that the planet has just come out of a period of rapid diversification of the survivors. Yes, I know there are Deity-like beings in this setting, but they havent done much other than ensuring that when their pet projecthumanitywas dropped on the planet, they could eat the local wildlife. Of course, that means the local wildlife can also eat the humans
And why was humanity placed there? Well, I cant tell you everything. I know why, and thats enough. Nyah!
The other thing to note is that with the ability of intelligent beings to use magic, and that ability allowing them to play with biology, intentional fiddling with the wildlife can and has happened in Gayajans present day. Since humans only showed up 16,218 years ago (they keep good records), well focus on what was around then since it will form the basis for whats around now.
Ignoring the microscopicwhich we really shouldnt but Im writing a story, not a biological treatise (you in the back, shut up)there are three kingdoms of life on Earth: Plant, animal and fungus. Generally speaking, plants are autotrophs; that is, they make their own food. Animals and fungi are heterotrophs; they dont make their own food and have to eat something. If youre an autotroph, there are two sources of energy on the planet, one of themsunlightcoming from above, and the otherhot minerals rising up from the Earths interiorcoming from below. In both cases the primary energy source is nuclear, fusion in the sun and decaying radioisotopes in the core (as well as retained heat from the formation of the planet, but the stuff that made up the Earth came from stars forming elements when they went kablooey a few billion years ago)but nuclear energy cant be used directly. Biologicals that we know of cant handle the high energies involved in what we consider nuclear power; the gamma rays, x-rays, alpha and beta particles and so on. They tend to have a destructive effect on biological material.
But on Gayajan, remember, we dont have gamma rays. We have etherons. And etherons dont necessarily affect life the same way as radiation were familiar with. So etherons mean theres a third source of energy: Heat from below, light from above, and etheric energy from wherever. And something was given the ability, through manipulation a long time ago, to exploit it. No, they arent microscopic entities that exist in the blood and give people special mental and physical abilities to manipulate the Forc er etheric energy.
They are the crystaltrees.
Now they arent really plants at all. Not evolved from them, not related to them. They are plantlike in that they are autotrophs, producing their own food from water and nutrients, and therefore have some physiological similarities. A root, collecting nutrients, water and required minerals from the ground and anchoring the organism and thats about it. They get their name because they really do have crystals growing in them. The crystals are formed from precipitated silicate and carbonate minerals containing what wed consider radioactive elements such as uranium and thorium. On Gayajan these elements release etheric energy. The crystaltrees concentrate etherically-active elements from the ground and water and form crystals with those elements in them. The energy released is used by the crystaltree to power the chemical reactions which it uses to produce its food from the water and nutrients it absorbs. Basically a nuclear-powered plant (no pun intended).
With their own internal power sources crystaltrees would seem to have an advantage over the other autotrophs, but they have serious limitations. For one, their batteries will run dry without being able to absorb more of the critical elements they need which are, for geochemical reasons, not as common at the surface as the normal nutrients plants require.
This will limit their ability to get large to places with abundant sources of those elements. The other problem is that other organisms would seek out these sources of power, so crystaltrees provide a convenient marker (not to mention a source in themselves).
Of course, crystaltrees can fight back. Heres a sampling.
Resembling a thick stump with a globe of branches emerging from the top, the steambrush deals with attackers though thermal warfare. Each branch contains a long crystalline chamber containing water. The ethericactive elements in the crystal heat the water to the boiling point and beyond, the crystal insulating the rest of the organism from the heat. When a branch is broken, the crystal chamber snaps open and releases a blast of superheated steam, usually enough to dissuade an attacker from trying to bother the steambrush any more. Some organisms have entered into symbiotic relationships with the steambrush, such as the whistle tree. A normal plant, the whistle trees trunk is covered by small outward pointing steambrushes. In exchange for providing water and nutrients (as well as the ethericactive elements the tree cant use), the streambrushes provide protection for the tree. The name for the tree comes from the whistling sound produced by the release of superheated steam from the streambrushes.
Not needing sunlight, as well as being able to produce their own heat, crystaltrees have an advantage in Gayajans arctic regions during the long winters. With no need to become dormant they can continue growing throughout the year, thus creating shelter for plants and animals in an ecosystem that we dont have any equivalent for on Earth. Of course the frozen ground limits the mobility of the groundwater they need to transport the elements they need, which is why the snowtrap evolved. The equivalent of a pitcher plant, but much larger, the plant is almost totally subterranean with an extensive root system and a large, hollow bulb big enough to hold the equivalent of a moose. During the brief summer the bulb fills with water and is relatively harmless. During the winter, the top few centimeters of the water freezes, the rest kept fluid by the snowtraps generated heat. When a sufficiently large animal breaks through the ice and falls into the bulb, poisonous needles spring out and impale the animal, quickly paralyzing it. It sinks into the water and is dissolved by digestive acids released by the snowtrap. With the top layer of ice covered in snow, snowtraps are invisible killers waiting for a victim. Fortunately the heat of the plant means that it leaves traces in the surrounding snow that are visible to creatures like humans who recognize the signs and can avoid the danger.
The most common type of crystaltree, chimneytrees are the most treelike of all, resembling a palm. The leaves, however, are not leaves at all but organic radiators releasing the massive amounts of heat generated by the crystaltrees highly ethericactive chemical processes. Named chimneytrees because of the steam visible coming off them on cold days, the organisms live fast, growing up to several centimeters a day with sufficient nutrients and water. They form the basis for the arctic forests, the heat they put out sought by other organisms for shelter. Chimneytrees are also among the first organisms colonizing new land created by volcanic action (if the ground has sufficient quantities of ethericactive elements). Their fast growth, however, means that they rapidly deplete the soil of ethericactives. A common ecosystem on the planet involves chimneytrees providing a foundation and then dying out to be replaced by plants who used the chimneytree forest for protection.
Of course there are morebut hey, remember, some things to myself. Next time, well look at some of the animals.