◒ Speciation & Evolution Lab

Mission: watch one population split

Begin with one interbreeding lizard population. Raise a barrier, change environments, and follow allele frequencies until the separated populations become reproductively isolated.
Variation
Isolation
Divergence
New species
Green traitSand traitGene flowSelectionMutation
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Evolution controls

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35%
1.0%
60
0generations
0%genetic distance
1species

Allele-frequency evidence

Green: forest allele · Orange: sand allele · Purple: reproductive isolation

Tracked object

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TipTap an organism, island, barrier, or migrant

Camera

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Teacher tools

Teacher-guided complete lecture

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What to watch: narrated changes are highlighted with arrows and visible ecosystem changes.
Step explanation: The visible ecosystem will change to match the current narration.
Choose a language and voice, then begin. Population movement, selection, mutation, isolation, and divergence will be demonstrated automatically.
Ready. Narration will not start automatically.

Chapters

Learning objectives

  • Explain evolution as change in inherited trait frequencies across generations.
  • Compare mutation, natural selection, genetic drift, and gene flow.
  • Explain how geographic isolation permits divergence.
  • Connect reproductive isolation to speciation.
  • Predict effects of population size and environmental contrast.

Key concepts

Variation

Mutation and recombination create inherited differences within populations.

Selection

Traits affecting survival and reproduction can become more common.

Gene flow and drift

Migration mixes populations; random sampling changes small populations strongly.

Speciation

Separated populations can diverge until they no longer exchange genes successfully.

Scientific model

The simulation tracks one simplified color-associated allele in two populations. Selection moves each population toward its local optimum, migration mixes allele frequencies, mutation introduces change, and drift is stronger in small populations. Genetic distance and reproductive isolation are educational indicators, not direct measurements for real species.

Suggested experiments

  • Raise the barrier while keeping both environments the same.
  • Use strong environmental contrast with high gene flow.
  • Compare drift in populations of 15 and 100.
  • Remove the barrier after divergence and observe the hybrid zone.

Common misconceptions

  • Individuals do not evolve during their lifetime; populations evolve across generations.
  • Mutations are not produced because organisms need them.
  • Natural selection is not random, although mutation and drift include random components.
  • Speciation usually develops gradually rather than at one universal distance value.
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