BIO 202 — Lesson 20

The populations' treeOne population of fish (grey bar, left) keeps splitting in two. Each bar is a population, from the generation it began to the generation it split or the present; the letters name the populations living now.The red lines inside: at one locus, one chromosome from each living population, traced back through its parents, generation by generation, until they meet.Right: that locus's tree beside the populations' tree. Below it the eight loci traced: ✓ its tree matches the populations' tree, ✗ it does not. Click one to draw it.

Every pair of populations:A dot for each pair of living populations, at the number of generations since they parted.F_ST: how different their alleles are, as in Lesson 19. A hybrid: a young fish with one parent from each, as in Lesson 19 C: a new allele from one with a new allele from the other is an incompatible pair with chance 0.02, and one kills it.

StepEach generation every fish is replaced by young of two parents from its own population, as in Lessons 17 and 19. A population splits in two with the chance you set, each half its own population from then on, never meeting again; at most six populations.Go plays 400 generations, one tree. A slider joins the controls as the steps open it.

chance a population splitsEach generation, each population splits in two with this chance.

practice — a run with this ticked does not count

To finish

Work through the nine steps. 0 of 9

Observed data: Anolis lizards

R code

Lesson 20

Size along the treeEach population's average size, generation by generation; where a line forks, the population split.Every allele at every locus adds a little to a fish's size or takes a little off: the grey alleles, and each new allele as it arises. Nothing helps or harms a fish of any size.

To finish

Good job!