Relative Fitness Calculator
The Relative Fitness Calculator estimates Relative Fitness (W) based on survival and reproductive rates. This tool helps biology students and researchers compare the evolutionary success of different genotypes. Whether you are analyzing natural selection, predicting population changes, or conducting genetic research, this calculator provides clear, actionable insights into genetic advantage.
How Relative Fitness Is Calculated
Relative fitness measures how well a specific genotype survives and reproduces compared to others in the population. To calculate this, we first determine the absolute fitness for both your genotype and the reference genotype. Absolute fitness is found by multiplying the survival rate by the reproductive rate for each. Finally, we divide the absolute fitness of your genotype by the reference genotype's absolute fitness. This standard biological equation ensures you get an accurate ratio representing evolutionary potential.
W = (Survival Rate × Reproductive Rate) / (Ref Survival Rate × Ref Reproductive Rate)
Where:
- W = Relative Fitness
- Ref = Reference Genotype values
- Calculate the Absolute Fitness for your genotype by multiplying its Survival Rate by its Reproductive Rate to find total reproductive output.
- Calculate the Absolute Fitness for the reference genotype using the same method.
- Divide your genotype's Absolute Fitness by the reference genotype's Absolute Fitness to normalize the data.
What Your Relative Fitness Means
The Relative Fitness (W) value you receive tells you how successful a specific genotype is compared to the reference. A score above 1.0 means the genotype has above-average success, while a score below 1.0 means it is less successful than the average.
Advantageous Traits
If your W value is greater than 1.0, the genotype is beneficial. For instance, a score of 1.5 suggests a significant advantage, meaning this trait will likely increase rapidly in the population over time. Even a score of 1.2 shows a modest benefit that leads to gradual growth.
Disadvantageous Traits
If the value is below 1.0, the genotype is struggling. A result between 0.5 and 0.79 indicates moderate disadvantage, causing the trait to decrease in frequency. A score below 0.5 suggests it will be eliminated quickly unless other factors maintain it.
Important: While generation time is an important input for understanding population speed, this specific calculation focuses on the ratio of reproductive output to determine genetic success.
This tool is designed for educational and research purposes only. It provides theoretical estimates based on standard biological equations and should not be used as the sole basis for complex population modeling without consulting a professional biologist.
To verify your results, track the actual population frequency over several generations and compare it to your calculated fitness prediction.