Most evolutionary biologists agree that earth's first living organisms were prokaryotes---tiny, relatively simple cells that appeared somewhere between 3,800 and 3,500 million years ago (Mayr 44). These bacteria-like units lacked most of the internal structures that are familiar aspects of "cells" today: no nuclei, no chromosomes, no organelles whatsoever. They reproduced by splitting apart, moved via wiggling whiskers of protein, and lived basically everywhere that was wet, from deep-ocean sulfur springs to surface-water.

Then, around 2,800 years ago, something drastically different happened. Writes Ernst Mayr, acclaimed evolutionary biologist: "the origin of the eukaryotes was arguably the most important even in the whole history of life on earth. It made the origin of all the more complex organisms... possible" (Mary 47). Eukaryotes first appeared when certain greedy prokaryotes devoured other prokaryotes---then decided not to digest them. Instead, the consumed cells formed a symbiotic relationship with their predators, serving as mitochondria and chloroplasts (producers of energy); later, even more symbionts moved in to function as other organelles.

The advent of eukaryotes made possible (among other things) sexual reproduction. This evolutionary milestone allowed for greater differentiation among species via gene-sharing and gene-swapping. Such periodic rearrangements of DNA in turn led to a wider variety of genotypes, which led to a wider variety of phenotypes that could then confront (and hopefully survive) in a wider variety of environments.

Eukaryotes were also the first practitioners of true multicelluarity. Writes Mayr: "There are many forerunners of multicellularity among the bacteria" (Mayr 49). However, simple groupings of cells couldn't work together towards a common purpose---the earliest "multicellular organisms" were more organizations than organisms. It took an increase in size and a concurrent "division of labor among the cells of such aggregations... [to merge] into genuine multicellularity" (Mayr 49). Among animals, the first multicellular organisms were simply layers of cells stuck together. Next came sponges, then flatworms.

Flatworms (Platyhelminthes) were simple, soft-bodied, bottom-dwelling scum-feeders. They were the first truly mobile multicellular animals; they subsequently evolved into more and more complex forms, adding mouths and muscles, and, eventually, vertebral columns and backbones.

The first true vertebrates were fish that somewhat resembled today's lampreys (users.rcn.com). These fish eventually developed full skeletons. Such skeletons allowed them to evolve fins, which, sometime during the late Denovian, grew into legs.

Called tetrapods, the first four-legged animals didn't actually make it to land until the Carboniferous, when they hauled themselves out of the water and onto the beach as the first amphibians (users.rcn.com). Sporting lungs, limbs, and eyes, these semi-aquatic animals dominated the planet for most of the Carboniferous era. But as the Carboniferous became the Permian, the earth dried out, cooled off, and many semi-aquatic amphibians became completely land-adapted.

Though these Reptiles didn't look much different, their waterproof skin, hard-shelled eggs, and---maybe most importantly---semi-divided heart gave them the tools that allowed them to control the planet for the next 235 million years.

At the same time, however, a little side-branch of Reptilia began developing its own uniquely bizarre characteristics: warm blood, and fast-running legs held underneath (not on the sides) of the body. These were the Pelycosaurs, which became the therapsids, which finally became the mammals.

Mammals appeared around 180 million years ago, during the Jurassic---dinosaur heydey. Their warmblooded, hairy bodies, differentiated teeth, and ability to give live birth and nurse didn't really help them much until the late Cretaceous, when the dinosaurs disappeared and mammals leapt in to fill the lizards' (rather expansive) evolutionary niche (users.rcn.com). The first mammals were tiny, shrew-like creatures which lived precariously beneath the feet of giants.

During the late Cretaceous, when the mammals began their first serious diversification, some tree-shrews developed special adaptations to their life in the trees. These included prehensile tails, opposable thumbs, bigger brains, and stereoscopic vision (www.emc.maricopa.edu). These tree-dwelling creatures came to be classified in the Order Primates.

Around 55 million years ago, the early primates diversified into two groups: Old World Monkeys and New World Monkeys.

A few million years later (36 mya), the Old World Monkeys sprouted two side branches: the lesser and greater apes. Apes lost their tails and a portion of their arboreal flexibility; in return, they gained larger brains, longer arms, and the ability to walk upright for short periods of time (www.emc.maricopa.edu).

Sometime around seven million years ago, a few species of ape became fully bipedal. These were the first hominids, immediate ancestors of humans. Beginning with the australopithecenes, hominids gradually got taller, smarter, and faster (as their spines and pelvises straightened and their bipedally-adapted "back arms" turned into full-fledged legs).

Around four million years ago, they picked up tools. At two million years, they were using them to kill, skin, and consume meat. A few thousand years later, they spread out of Africa and into Eurasia. Finally, between 100,000 to 500,000 years ago, the first "true" Homo sapiens appeared. During some part of this long journey, self-awareness developed, and, after it, all the concurrent ingredients for civilization: language. Art. Social structure.

The rest, as they say, is history.

Motion; small. Little ripples through. Directed, emanating---from? Skin tenses, feel for ripples, little brushes, tiny footprints, leading---there! Direction: there. Whip-wheel turn, wiggling of skin-fingers, ripples tap across surface until. Direction: there! Distance, not far. Skin-fingers wiggle, row, push. Little ripples closer. Closer. Wiggle, row, push. Closer. Wiggle, row, push. Closest. Row, coast. Ripples stop, there rippling. Small. Skin-fingers probe, scan sides, body: small enough. Skin-fingers retreat. Tensing, balling, crouching, compacting. LEAP! Forward snap-extend, entrap, enclose. Little ripples outside, outside... inside. Rippling inside. Rippling stops. Rest; satisfied. Later: motion; small. Little ripples through. Directed, emanating---from? Direction: front! Distance, close. Skin-fingers wiggle, row, shove. Tense and ball and crouch and LEAP! Forward snap-extend, entrap, enclose. Little ripples inside. Inside rippling, rippling, remains rippling. No rest; forward. Skin-fingers wiggle, row, push forward fast. Faster. Inside remains rippling; outside skin-fingers churn. Faster. Inside rippling slows; stops. Outside skin-fingers sluggish; slow; stop. Churning subsides to floating, being. Immobile---until. Later: motion; small. Little ripples through. Direction: front! Skin-fingers probe, scan: small body. Tense-ball-crouch-LEAP-snap! Little ripples inside. Inside rippling, rippling; outside skin-fingers quiver and twirl. Churn forward, faster, better. Inside rippling remains. Energized.

Ripples accumulate. Tense-ball-crouch-LEAP, tense-ball-crouch-LEAP. Inside rippling, rippling. Tense-ball-crouch-LEAP. Energy. Tense-ball-crouch-LEAP; growing gluttonous. Satiated but seeking, ripple-hungry, ripple-breathing: tense-ball-crouch LEAP. Until---

Symphony of rippling. Inside little ripples: rapid churn and pant, suck and spit of fluid and fuel; outside skin-fingers---longer, faster---undulate rhythmically. Directionally. Front forward, probed by spindly arms, not locomotive; back behind, propelled by supple oars. Specialized. Ahead motion; large. Spindly forearms billow, too small to cup waves. Their tips lick wave-crests, shave pate of each parabola. Tasting, testing---until. Forearms flail signal: bad taste! Inside little ripples heave, blow fuel backward. Rear-oars reverse. Away. Away from large bad-taste. Continue away---until. Later: ahead motion; middling. Forearms sway in familiar cadence: roll of movement without moving. Armtips brush head of each swell: smell, scan. Signal shoots back: familiar! Rear-oars ease into motion, paddling, cadence-coasting. Glide forward towards familiar, forearms quivering invitation. Closer---slowing---closest.

Outside forearms reach, link, caress. Inside rippling tightens, excited whirlpool-pant. Fluid curdles into loose wreaths. Outside, from familiar, spindly forearms reach, link, caress. Knitting supple latticework of arms. Closest, closest. Skins shiver together. Mesh. Melt. Inside: wall dissolving into window. Wreaths tighten, knotting into bows at center. From familiar, fluid sluices through window, wreath-laden. Little ripples wash wreaths together; tug at knots; interweave ends. Wreaths uncoil. Strafe: lines of tense snakes lying lengthwise, scales gently brushing. Mingling. Sharing. Little ripples lap tide-like at window, gnawing sills, widening.

Limp wreaths twine and separate, altered. Separate and condense: wayward lassoes curl back into unfamiliar bows. Bows spring apart, directionally shattered---forward, backward, side, side. Inside: sudden shuddering. Little ripples mimic bows' snap: pitch away from center, exploded cyclone, debris hammering against inside skin. Surface boils, stretches, sags into great bubbles. Outside skin balloons into cloverleaf. Inside skin quarters; little ripples herd bows into bubbles, irregardless of quality---quantity only, proportionately perfect. Bubbles lengthen---cloverleaf leaves tug for independence---inside ripples roiling---outside stretching---stretching---urgent---stretching---stretch-twist and final SNAP! Clover cleaves. Multiplied.

Sundered, some leaves wobble off to independent destinies. Others congregate. Interior wreaths determine: bigger, smaller, swifter, slower, fewer or more skin-fingers. Differences accumulate. Littler leaves re-form into clovers; clovers pirouette through until, meeting other clovers, stick like snowflakes. Lines spool together; flat fields of clover bump and split like sheet-ice; cones and spheres and whorls, timid drifting palaces. All shatterable; only stable forms survive. Survive and multiply, component clovers linking and blending and budding again. Stable form: thin flat whip, segmented---twines with another whip, segmented; clovers bud and burst: thick tuft of whips swims away. Budding continues, whips sprout and swell and kink---until.

Fat whip nosing along the bottom, tasting the mud. Behind, tail corkscrews through languid propulsion. In front, nub of head stirs sediment into clouds, then nurses them, puckering tiny mouth-sieve and screening the scum for food. Millions upon millions of clovers. As mouth sucks, the cloud sinks in the cold water. Sucking, smelling---there! A small, pungent dart spits from the disturbed earth; its warmth ripples back through the scum. Mouth-sieve gapes, tail thrashes: the dart jets upward, evasive. Another, more violent tail-thrash, and suddenly mouth-sieve drips with a warm scent, and the scum-cloud cools and stills, empty.

Sieve masticates briefly. Tail slows, returning to weightless amble. Oars slowly upwards, towards warmer water. Atop head, small round circle tingles. As the water warms, tingling intensifies: sense of great presence---not food---filling the water, like an enormous transparent dust-cloud. Circle tugs body inexplicably upward, towards tingling; but below, a hot wiggle and concurrent puff of scum draws attention. Mouth-sieve gapes; head decides; tail slaps at the presence and away, towards sure food. Only circle still gazes upward, drinking in the great presence, not-food and not-warmth. Light.

Fat whip returns to the bottom. But on head, small circle growing: splitting and sliding down sides of head, to hang bulbous on either side of mouth-sieve. Sieve deepens, lengthens, collapsing from a concave pucker into a hinged half-moon. Behind hinge, slits appear. Slits ripple, rhythmic breathing matching interior suck and spit of fuel. Inside, condensing to usurp one long linear stretch, stiff thorn skewers body lengthwise. Then extends roots, segmented lances that drop through body like sounders, drawing flesh along, pushing through under-side to swing below, paddle-shaped protuberances. Thorn threads tail; tail lengthens, strengthens. Tips of body-paddles bud, fanning into crooked, jointed ginko-leaves.

Below, tail and paddles churn the undersea mud, searching for hardness. Above, bullish neck cranes towards the water's surface, filmy eyes searching the light which dribbles down, dappling the murk. Darting shadows through the light-bars betray the movement of food. Locating a brittle crest of sand, paddles shove hard. Tail follows with a thrash; together, scull upwards. Mouth opens, and the water swirls past nubs of teeth. Eyes glossed against the sunlight affix a drifting slice of shadow: food. Sculling harder, tail and paddles bullet upwards. At the last moment, the shadow starts; with a tiny explosion it launches straight upwards, disappearing into the light. Tail and paddles backpedal, try to slow---fail. The water cleaves, and head breaks into light.

Slits flap for water that isn't there. Eyes shutter just as rapidly, but with excitement: panting in the immensity above the surface. Below, paddles bicycle to hold head above water. When eyes discern a brown hulk---enormous, not-food, not-moving, but mottled with a haze of smaller darting shadows---tail beats automatically towards, while paddles maintain the vertical. As head skims laterally across the surface, skin hardens, drying into leathery pebbles. Tail emaciates, shedding layers like husked corn. Simultaneously, paddles lengthen, ginko-leaf tips splitting into cushioned hooks. The watertight mist clears from eyes. As head emerges from the shallows, rustling the wet stalks of amphibious plants, gasping slits flatten, sewn back into neck folds. From inside neck, slits descend, swallowed into chest. Settle between forepaddles, and swell and striate until tiny holes pop open at tip of nose. Holes flare: a long, wet, questioning blow. Breathe.

With a final yawn and heave of squat legs, it hauls itself onshore.

It's hungry and horny, but hungry comes first. Shaking the algae-green mud from its flanks, it waddles off across the beach. Destination: an umbrella-shaped spine of low bushes, surrounded by a roulette of neat holes. As it approaches, it slows, lowering its nose to snuffle at the rim of each burrow. It pauses above one which reeks of recent motion. Then, sweeping its tail back, hammers the loam about the hole. A cough of musky grit; a chitinous rattle; something sleek and obsidian clatters over the rim---SNAP! The chitin crumples between twin pliers of serrated teeth. Food oozes out. Acrid, sloppy.

Satisfied, it carries its dripping meal back to the warm sand---until. Its nose registers the peculiar, familiar scent before its eyes recognize the pug-nose, squat legs, and thin stiff tail. It snorts. A welcome pungency. The familiar rises as it approaches, tail gently stroking the sand beneath. It assesses: fat, healthy, strong; capable. It snorts again. The familiar hoots, then wheels, slowly, presenting hindquarters beneath a bobbing tail. The air reeks almost painfully; its eyes hook the swaying rump. Suddenly with a bellow, it clambers forward, dropping its meal, and heaves itself up across the familiar. For a moment, tails slap in a fierce jackhammer convulsion; then it sags, sated. Grunting, the welcome wriggles free. It simply slouches in the sand, exhausted, beside the gooey remains of its meal.

As the familiar struts off, it wilts into a splayed hibernation, drinking the light-warmth through its cobbled skin. But the light is failing, purpling down through the damp air into a chilly fog. Plants unfurl, grown lustrous with moisture; their broadening shadows flood the beach. Its skin pimples; its eyes film. It lacks the energy to chase the rim of warmth. Beneath its cooling belly, ferns push through the sand. Nearby a sapling crusts with bark, doubling its height. Sea and sky recede, divorced by a sudden canopy. As the purple cools to blue and finally to black, it shivers and raises its head. The pimples along its back sharpen. Then suddenly sprout: ridges of soft grass seep through its skin. Its blunt nose tapers beyond the bone, and a tiny tourniquet bubbles up at the end, wiggling. At the same time its legs shrivel and fold, knees snapping the opposite direction, and its entire body shrinks, evaporating to a mere bump in the depression its body once filled.

Inside, its organs shift and sculpt: the heart sews dividing walls, then accelerates to a frentic purr; the lungs deepen; the blood warms. It blinks, quick furry lids over massive anterior eyes. No longer exhausted, it scrambles from the dimple of its former body, pink hairless toes grappling the slope, pink hairless tail lifted for balance. Its thick hair ruffles against the dampness. Warmth.

Beyond, the nighttime jungle moans and thunders. The smallfur swivels veined, seashell-curved ears to catch the noise; its thicket of whiskers trembles across the wet loam. An approaching rumble sets its fur on end. Squeaking, it scuttles for the safety of a low mesa of ferns. Only its quivering nose peeps out from beneath a curling frond, testing the ripples of air which forerun their massive maker.

The ripples grow; a dusty, metallic spice rides the heaving air. The smallfur darts further into the shadows. It recognizes the smell: a trunk-leg, young and reeking panic. Not immediately threatening, but large and careless with its saucer-shaped feet. Moving quickly, too---the shriek and snap of rent trees accompanies the mounting ground-thunder. Cowering, the smallfur waits. The thunder rolls closer---closer---breaks! The smallfur yelps involuntarily as the fern ceiling above it shreds. Massive shapes clog the air. The ground explodes in loam tornadoes; it pitches away under the smallfur's feet, and the world eclipses beneath a behemoth shadow. The smallfur shrieks---

---and then it's over. The trunk-leg crashes away through the jungle. In its wake, the disturbed earth resettles itself. The smallfur sneezes. Lifting its head, it tests the air: stiller, drier, warmer. Brighter; the trunk-leg has plowed a canal through the canopy, and dewy light washes the leaves. Far off, the smallfur hears a treetop peeper colony ply the greying sky with wails. Closer, a far more welcome sound: the morning chirps of an unfamiliar smallfur warren. This smallfur yawns, suddenly fatigued. Because of the trunk-leg, it spent the night abroad in the jungle, away from the warm safety of its hole. Cocking its head, it scents out orientation; then, determining the direction, scrambles off in the direction of its own warren.

As it scampers, the trees thin around it. Morning lances through the canopy, and with it an eerie stillness. The air, cooler now, still pipes with the static of tiny furry voices; only the thunder has rolled away. Its dangerous musk retreats before a new tide, pungent and ubiquitous and seemingly endless as the sea. As the smallfur scampers, they sprout: unfurling all at once, like wind-driven flags, curling up the trunks in plump sensuous glory, drowning the forest floor in waves of carnal red and yellow---flowers. The smallfur trots unperturbed through these rainbow carpets, choked with pollen and abuzz with insects. Its warren lies at the base of an ancient oak turreted by climbing red-blossoms.

Achieving the bole, it claws onto a root and peers up, chirping. Answering hoots return from the shady branches; luminous corn-colored eyes blink between the red flowers. It begins the ascent.

The smallfur's short clawed toes scrabble on the rough bark; its peggy forelegs struggle for foot-holds. In response, as it climbs its limbs extend, stretching away from its rapidly-bulging shoulders like stems from a bulb. Its toes bud extra joints; padded flesh consumes their rough digging nails. Simultaneously its eyes wax into bright saucers, their distended size ironing flat the contours of the smallfur's face. They pinch off its long whiskered nose and press its jaw flush with its forehead. Behind, its hindquarters ripen with muscle; its tail drops behind like a curling vine, the bone sucked out. The smallfur lassoes branches as it ascends.

Inside something else is occurring. Behind its ears, the smallfur's cranium swells. Its fidgety eye-motions slow; its movements protract; pausing, it peers up the soaring trunk, estimating the easiest route upwards. Beneath its tail, between its hindlegs, swinging lumps shrivel and absorb; they relocate, softer and buttoned, below the collarbone. At the same time the smallfur's abdomen pouches, soaking blood from the heart. Its belly burns with the growth. Hooking spindly thumbs about the oak's fat vines, it pulls itself skyward through a net of flowers. Ignoring the familiar, cyclic pain.

Finally, reaching the branch where the clan perches, thumbs and tails interwoven with leaves for support, she squats down amongst her family. They hoot greetings. Her youngest sister passes her a spike-fruit; she accepts graciously, combing one hand through the sister's back-fur as thanks. With the other, she nimbly husks the spike-fruit before gulping it down. The twisttail troop spreads out along the branch as the sun arches into the sky. Noon sizzles through the canopy, somnolent. Her family curls into the hammocks where branch meets tree to nap, or perch drowsily on a shady mat of leaves. She pillows herself against her sister's warm back. Though her sister chitters a half-hearted complaint, she quickly relents, appreciating the extra warmth. They fall asleep to the muffled, lonely calls of noonday birds.

She awakes to screaming. Her family vaults over her in terror, shrieking alarm calls. Birds swarm past, a storm of startled feathers. Their hectic wind knocks her from her perch, and she tumbles down the bole of the tree. Branches thrash her face. Her sister leaps awake a moment later; she clings to vines for support, too frightened of falling to flee. As the twisstail slides helplessly down, by chance her head wheels upwards and she sees it: there! between the jet of white birds, a slash of yellow. She howls at her petrified sister, but it's already too late. The spot-tail pounces---she hears a shriek---it stops---the birds clear---she finally snags a branch and swings around, eyes searching desperately upward.

Smoky green eyes regard her across a yellow snout that's slowly staining red.

Silently, the twisstail retreats over the ground. She avoids the branches; they're too painful at the moment. Only when she is far enough away does she lift a keening mourning cry.

Her remaining family has gathered on the edge of the forest, where grasslands mingle with the flower-thick eaves. She rejoins them without comment. The troop gives her wide berth; only her elder sister approaches, cooing softly. She leans into her sister's body, and together they sit, ringed by the wary troop, and watch the sun go down.

Night falls. Stars wheel. The twisttail cranes her head to watch them, her spine straightening with interest. The savanna-grass seems to shorten as she gazes, encouraging her view. She gurgles occasionally at her sister, who replies with a stroke or a groom. Their heads swell against the sky. When she finally lays down to sleep, it is flatbacked: her tail has shortened, legs lengthened; her frame is fuller, shoulders broader. A plump, quick-woven mat of grass serves as her pillow. She sleeps, perchance to dream.

When dawn arrives, she stands up and walks away across the grassland.

It's hunting time.

She knows that Silver-foot---the male troop leader---dislikes hunting. It's dangerous, and the meat is sparse and stringy. He prefers root-digging, profitable and much safer. But she's not hungry for yams. She's not really even hungry, not for food---a feeling she's never felt before. The green eyes stalk her sleep. So she heads for the stream, and the deposit of black shale lining its banks. The troop has been mining this cache for awhile now, and several big stones already lie splintered in the creek bed. She ought to be able to scrounge several good, sharp points, even without help.

She's surprised, upon arrival, to find her sister Game-leg already there. Crouched near the water, Game-leg is shaving down an obsidian handaxe. She grunts as her sister approaches. Then she proffers the handaxe. Accepting the tool from Game-leg, she squats down to continue the work. The sun glints from its sleek facets, wheeling shards of light across the stream. Her eyes follow their progress. They flash over the pebbled creek-bed, lancing the two dark shadows that float opaquely on the water's surface...

She looks closer. One of the shadows glitters---familiarly. She lifts the obsidian axe; one shadow replies, mimicking, dazzling the water with light. The second does not. She examines it. This shadow too seems familiar---grey full chest, flicker of well-loved expression, slightly humped back tapering into a crooked foot, injured long ago in a fall from a spike-fruit tree... dropping the handaxe, she turns to the other shadow. The sparkles quench; what remains is a face, unfamiliar. She reaches out to stroke it; instantly its hand appears, blocking her view. She removes her hand; it follows. She tries it again: the same. Perplexed, she chitters with frustration; its mouth gyrates in silent reply. Its mouth... its thick, black lips are cracked, and red slashes line its face. They aren't claw-injuries---instead, they resemble thorn scars, or the whip-welts of branches that might be incurred in a fall from a tree... they hurt, she remembers...

Her nose is almost to the water now. The shadow's eyes captivate her: yellow, moony, captivated. She stares. Unfamiliar but---known. She touches her scars, examines them in the water: red, red, no wonder they hurt so much. But not as much as--- It was a bad fall. Scars---eyes---hurt---sister---face---mine. Mine.

Me.