You are a Phataginus volucris, a Winged-Screecher, clinging to the canopy of Virexa. Trees reach up to two miles high, with the ground being covered by a great fog.
Build your creature. Face what's coming. Watch natural selection decide whether traits prevail or vanish from the gene pool.
Virexa is a jungle planet where the ground is almost irrelevant. Towering trees rise miles into the sky, their upper branches forming entire ecosystems suspended above a permanent fog layer. The forest floor is dim and quiet, while the canopy above is alive with movement, sound, and color. Sunlight filters through in narrow beams, creating dramatic contrasts of brightness and shadow. Species on Virexa are adapted to vertical living, falling is often fatal, and survival depends on gripping, gliding, or climbing with precision.
Skywood Giants
Hollow trunks forming habitats; bark dense enough to anchor communities
Mistcatcher Ferns
Extract water directly from cloud cover, no rain needed
Canopy Stalkers
Long-limbed apex predators; primary threat to our species
Petalgliders
Small gliding mammals; primary prey source; abundant in treetops
fa·TAJ·in·ous voh·loo·crease · The Winged-Screecher
Locomotion: Winged glider, medium speed
Size: Medium-bodied
Teeth: Sharp + flat mixed (shifting to pure carnivore)
Skin: Chameleon camouflage (being lost)
Hands: Grippy frog-pad fingers
Speed: Slow on ground; agile in canopy
Tail: Long prehensile, grips branches
Voice: Piercing screech, used in mating
The Winged-Screecher has two sexually selected traits to attract partners. These traits didn't evolve to help survival, but rather are preferred by natural selection because they improve reproduction.
Vivid wing patterns signal genetic fitness, with brighter individuals attracting more mates. These patterns are costly to maintain, so only truly healthy individuals can afford them.
Males perform complex screech calls, with more elaborate calls correlating with health and fitness. The screech allows for communication with only other Winged-Screechers.
Choose one trait per category. Your choices will be tested by the events ahead, some will save you, some will reveal how natural selection works in ways you didn't expect.
A Pandemic Strikes Virexa
A foodborne disease moves silently through the food chain. Vision blurs. Limbs go numb. Within two seasons, 90% of all Winged-Screechers are dead.
The pandemic killed 90% of the population at random, causing a sudden population crash that narrows the gene pool to the genes of just a few. This is known as the Bottleneck Effect.
A sudden population crash leaves survivors holding only a tiny fraction of the original gene pool. Rare alleles vanish entirely. Common ones may disappear too, purely by chance.
Random shifts in allele frequency caused by chance, not selection. The smaller the population, the stronger drift becomes. A bottleneck supercharges this effect.
The pandemic didn't affect the Petalgliders. Vegetation collapsed, but prey exploded in population. Individuals with sharp teeth hunted efficiently. Those without, starved. Over generations, the population shifted entirely: flat teeth disappeared, sharp teeth became universal. This is directional selection, one extreme trait wins, and the distribution moves toward it.
Vegetation Dies: Petalgliders Swarm
The disease ripped through the food chain. Plant life withered. But the Petalgliders, untouched, exploded in population.
The Winged-Screecher shares structural similarities with other species, evidence of common ancestry. Two independent lines of evidence confirm this.
Homologous structures are parts of the body shared across species due to common ancestry, even when the function differs. The Winged-Screecher's forelimb has the same basic bone structure as the Canopy Stalker's clawed arm and the Petalglider's gliding membrane. Same bones, same ancestor, but different purpose.
Early-stage embryos of distantly related species look nearly identical. The more similar two embryos are, the more recent their common ancestor. Comparing the Winged-Screecher embryo to those of the Pangolin, Bat, Ape, and Pterodactyl reveals clear shared developmental pathways, a second independent line of evidence for shared ancestry, even though all of these animals have great phenotypical differences after birth.
Canopy Stalkers Go Silent
The Canopy Stalkers, apex hunters, have been decimated in their numbers. The energy spent on camouflage is energy wasted now...
The Winged-Screecher didn't always look like this. Three fossil iterations document how this species changed across deep time, each one shaped by the selective pressures of its era.
Flat teeth. Small size. No tail.
Tail present. Larger ear holes. Larger size.
Longer spine. Small ear holes. Sharp teeth. Larger size.
Iteration 1 shows a small, tailless creature with flat teeth, suited to a plant-heavy diet. By Iteration 2, a tail has emerged alongside larger ear holes and increased body size, reflecting changing environmental pressures. Iteration 3 shows a larger animal with a longer spine, sharp teeth, and reduced ear holes, the profile of a carnivore shaped by a world where prey was abundant and predators were gone.
A Tree Falls: The World Splits
A Skywood Giant crashes through the canopy, triggering a cascade. Dozens of trees fall like dominoes. A portion of your population is cut off in a darker, lower region of the forest.
The cladogram places P. volucris within its evolutionary family. Sister taxa, species sharing the most recent common ancestor, are grouped closest together. The two sister pairs in this tree are Pangolin + Winged-Screecher and Bat + Petalglider.
The falling Skywood Giant geographically isolated a population. No gene flow between groups. The geographic barrier is a pre-zygotic isolating mechanism.
New prey emerged at different canopy heights within the same territory. Individuals specializing in different niches, different tooth sizes for different prey, stopped competing directly. Without geographic isolation, niche divergence drove speciation.
Prevent mating from occurring at all: Geographic isolation (tree fall), habitat preference differences (upper vs. lower canopy), and behavioral divergence (screech patterns no longer attract cross-population mates).
Reduce fitness of hybrids if mating does occur: Hybrid offspring may have mismatched teeth for their habitat, incompatible grip pads, or intermediate wing patterns that attract neither population, reducing reproductive success.