Understanding Absolute Fitness Frequency
Absolute fitness measures how much a genotype contributes to the next group. It can use survival, birth rate, fertility, or a combined value. This calculator turns those values into updated genotype and allele frequencies. It helps when selection is not described only by relative fitness. The method also shows mean fitness, which is the weighted average success of the whole population.
Why This Calculation Matters
Frequency change is important in evolutionary physics models, biophysics simulations, and population dynamics. A small fitness advantage can grow across generations. A lower value can remove an allele slowly or quickly. The result depends on the starting frequency, the heterozygote value, and the mating assumption. Because the tool shows each generation, the trend is easier to inspect.
What The Inputs Mean
You may start from allele frequency or observed genotype counts. Allele frequency mode assumes Hardy Weinberg starting proportions. Genotype count mode uses your observed AA, Aa, and aa counts. The fitness boxes accept absolute values. They do not need to add to one. They only need a consistent scale. For example, 12 offspring, 8 survivors, and 4 survivors can be entered directly.
Reading The Output
The output lists p and q before selection, mean fitness, genotype frequencies after selection, and the final allele frequency. If random mating is selected, the next generation is rebuilt from p and q. If selected genotypes are carried forward, the selected genotype frequencies continue directly. Both options are useful. They answer different modeling questions.
Practical Notes
Use realistic fitness values when possible. Very high or very low values can push frequencies fast. Zero fitness means that genotype leaves no descendants during selection. The population size field only scales frequencies into expected counts. It does not add random drift. For stochastic effects, repeat simulations with random sampling outside this deterministic calculator.
Common Modeling Choices
A dominant allele changes differently from a recessive allele. Heterozygote fitness controls that pattern. When Aa matches AA, the A allele is favored even when rare. When Aa matches aa, selection may be slow at first. Overdominance can maintain both alleles. Underdominance can make the final result depend strongly on the starting frequency. Always compare assumptions before using the result in reports.