Well, without reproduction... for now...
As you can tell by the title, I ran a Species Ecosystem Experiment. Involving multiple species under multiple niches. For the sake of isolation and movie science, we're on an Island.
Species Dynamics
Herbivores
Brachiosaurus (BRC)
Starting Population: 10
Predators: TYR, CRN, VLC (Pack), DLP (Pack)
Kills: TYR, CRN, VLC, DLP
Fights: N/A
Mamenchisaurus (MMN)
Starting Population: 4
Predators: TYR, CRN, VLC (Pack), DLP (Pack)
Kills: TYR, CRN, VLC, DLP
Fights: N/A
Edmontosaurus (EDM)
Starting Population: 4
Predators: TYR, CRN, CRY, VLC, DLP
Kills: VLC, DLP
Fights: N/A
Parasaurolophus (PRS)
Starting Population: 13
Predators: TYR, CRN, BRY, VLC, DLP
Kills: VLC, DLP
Fights: N/A
Triceratops (TRC)
Starting Population: 10
Predators: VLC (Pack), DLP (Pack)
Kills: GST
Fights: STG, TYR, CRN, BRY
Stegosaurus (STG)
Starting Population: 11
Predators: VLC (Pack), DLP (Pack)
Kills: GST
Fights: TYR, CRN, BRY
Pachycephalosaurus (PCH)
Starting Population: 9
Predators: TYR, CRN, BRY
Kills: GST
Fights: VLC, DLP
Gallimimus (GLL)
Starting Population: 20
Predators: TYR, VLC, CRN, BRY, DLP, GST
Kills: VLC, DLP
Fights: N/A
Carnivores/Scavengers
Tyrannosaurus (TYR)
Starting Population: 4
Predators: VLC (Pack), DLP (Pack)
Hunts: BRC, MMN, EDM, PRS, PCH, GLL
Fights: CRN, BRY
Velociraptor (VLC)
Starting Population: 18
Predators: TYR, CRN, GST
Hunts: BRC (Pack), MMN (Pack), EDM (Pack), PRS (Pack), TRC (Pack), STG (Pack), GLL, TYR (Pack), CRN (Pack), CMP, GST
Fights: PCH, BRY, DLP
Carnotaurus (CRN)
Starting Population: 2
Predators: N/A
Hunts: BRC, MMN, EDM, PRS, PCH, GLL
Fights: PCH, TYR, BRY
Baryonyx (BRY)
Starting Population: 5
Predators: N/A
Hunts: PCH, GST
Fights: TYR, VLC, CRN, DLP
Dilophosaurus (DLP)
Starting Population: 12
Predators: TYR, CRN, GST
Hunts: BRC (Pack), MMN (Pack), EDM (Pack), PRS (Pack), TRC (Pack), STG (Pack), GLL, TYR (Pack), CRN (Pack), CMP, GST
Fights: PCH, VLC, BRY
Compsognathus (CMP)
Starting Population: 28
Predators: VLC, DLP, GST
Hunts: N/A (Scavenges)
Fights: N/A
Geosternbergia (GST)
Starting Population: 10
Predators: VLC, BRY, DLP
Hunts: VLC, DLP, CMP
Fights: N/A
Using a random number generator, and a Google "Flip a Coin", I created an ecosystem for 8 days.
These are the results:
Population Declines:
BRC: 10 -> 8
MMN: 4 -> 2
EDM: 4 -> 3
PRS: 13 -> 3
TRC: 10 -> 7
STG: 11 -> 5
PCH: 9 -> 1
GLL: 20 -> 6
TYR: 4 -> 2
VLC: 18 -> EXTINCT
CRN: 2 -> 2
BRY: 5 -> 4
DLP: 12 -> EXTINCT
CMP: 28 -> EXTINCT
GST: 10 -> EXTINCT
By far, Compsognatus was the biggest decline, going from 28 to 0 in just seven generations. Additionally, Dilophosaurus was a big upset, having the remains of their species wiped out in Generation 4. Carnotaurus was the most stable species, staying at 2 the entire time.
