TEACHING MODEL · FICTIONAL GROWTH GENES
The stream laboratory
What is the seed? A seed is a number that starts the computer’s repeatable sequence of chance events. The same seed and settings reproduce the same trial. Keep the seed the same when comparing treatments, then try other seeds to see whether a pattern holds. It is not a biological trait or a measure of fishing pressure.
Settings apply when you start a new trial.
One fish = one model individual
Lengths in this stage
Length counts as a table
Inherited alleles through generations
Adult cohorts only. G is averaged over three fictional locations; separate frequencies appear below.
Stage records and allele frequencies
Compare saved runs
Save matching stages and generations. Up to 12 runs are stored on this device.
How this teaching model works
60 fish start each cohort. At each of three fictional locations, a fish has two alleles (G or g). Each parent contributes one allele per location. All adults reproduce at age 6 model years. Harvest acts before reproduction. Remaining female and male parents are sampled with equal probability within each sex. Their 60 offspring replace the adults and grow under the selected food condition.
There is no mutation or migration. Growth also includes a small random developmental effect. Large-fish capture uses probability weights that increase with length. The fixed cohort size and separate generations simplify the biology. These settings are not fitted to Mistassini data. The model does not identify real growth genes, predict catch, or prescribe fishery management.
Read all model rules ↗FIELD NOTEBOOK
Record your thinking
Use these boxes or your printed workbook. Your teacher assesses your evidence and reasoning.