BIO 202 — Evolution
Interactive simulations · Coe College
These are short, self-contained lessons. Each one asks you to make a prediction before you touch any controls, then lets you test that prediction against a simulation and against real data.
Lessons
Lesson 0
Prediction, noise, and the regression line
What is your best guess for y, and how wrong will you typically be?
Lesson 1
Variation and directional change
"No trend" is a distribution, not a single number. How big a trend does it take before you can see one?
Lesson 2
Model building and residual reading
Same data, two models, different stories. What the residuals tell you about the variable you forgot.
Lesson 3
Mendel, linkage, and gene dropping
Drop alleles through a pedigree and watch drift appear from nothing but fair coins.
Scaffolds — small, repeated practice
Short guess-and-check exercises. Each one drills a single concept across five rounds with different data or parameters. The concept is named only after you have produced it yourself five times. Read the top of each page for the rhythm.
Scaffold S1
"No trend" is a distribution
Predict the 95% half-width of a shuffle-null for slope. Fortis beak depth (two windows), LTEE (two windows), PETS Hyopsodus.
Scaffold S2
Residual reading across datasets
Classify residual patterns as clean / curvature / two clouds / heteroskedasticity. Pantheria mammals, Avonet birds, LTEE.
Scaffold S3
HWE genotype counting
Given p and N, predict the heterozygote count. Panmictic, pedigreed wild pop, inbred colony, Wahlund, plus one reverse-direction round.
Scaffold S4
Fixation probability
Predict the fraction of Wright–Fisher replicates that will fix the allele. Five (p₀, Nₑ) combinations.
Scaffold S5
Time to fixation scales with Nₑ
Predict the median generations until fixation-or-loss. Nₑ sweeps 20, 50, 200; p₀ sweeps 0.1, 0.5, 0.9.
Scaffold S6
Drift, selection, or both?
Classify five trajectories: three simulated at different (s, Nₑ), plus LTEE fitness and an FSJ SNP.
Scaffold S7
Breeder's equation, year by year
Predict R = h² · S for five different Grant-finch years. Drought, wet El Niño, character displacement, quiet years.
Scaffold S8
Selection coefficient from Δp
Given (p₀, pₜ, t, Nₑ), estimate s. Likelihood profile with 95% CI. Some rounds give tight estimates, some CIs span zero.
Scaffold S9
Mutation–selection balance
Predict q̂ for recessive lethals, additive lethals, and near-recessive edge cases — plus cystic fibrosis, where the formula visibly fails.
Scaffold S10
F and the heterozygote deficit
From genotype counts, compute F. Panmictic, pedigreed wild pop, sibling mating, Wahlund, heterozygote excess.
Scaffold S11
FST and migration
Three forward rounds (guess FST from Nₑ and m) and two inverse rounds using Atlantic cod from open-coast vs. inner-fjord populations.
Scaffold S12
Hamilton's rule across levels
Predict whether helping spreads when rB > C. Prairie dog siblings and cousins, turkey helpers, bacterial cooperation, plus an unrelated-strangers control.
Scaffold S13
Reading trees with rotated nodes
Click the sister pair in five phylogenies whose layouts are designed to fool you. After each answer, see the same tree redrawn.
Scaffold S14
Rates of evolution across intervals
Predict the median rate of change across sliding windows. LTEE at three interval lengths, Grant finches at 1 year, Hyopsodus at 0.5 MY — Gingerich's decline.
Scaffold S15
Phylogenetic non-independence
Predict naïve vs. clade-centered slopes across four Avonet trait pairs plus one Simpson's-paradox synthetic case.
Scaffold S16
The Dobzhansky–Muller snowball
Predict the number of hybrid incompatibilities as divergence time doubles. Rates grow as t², and the tally shows the log-log line.
Scaffold S17
Mutation target size and parallel evolution
Classify five phenotypes by effective mutation rate. Webbed feet, cave eye loss, lactase persistence, the placenta, hinged jaws.
Scaffold S18
dN/dS classification
Classify five genes by selection regime. MHC, Histone H3, the GULO pseudogene, SARS-CoV-2 spike, mitochondrial cytochrome b.
Scaffold S19
Convergence vs. drift vs. shared ancestry
Classify five repeated-pattern cases. Anolis ecomorphs, stickleback armor, Kolbe founders, cave eye loss, human mtDNA.
Scaffold S20
Species as hypotheses
Decide one species or two — and name the observation that would flip your call. Ring species, Rhagoletis, F2 breakdown, color polymorphism.