📚 Biology calculators
The biology calculators cluster covers introductory study math: population change and demography rates (including rate of natural increase), population genetics (allele frequency and Hardy–Weinberg p²/2pq/q²), lab rates (mitotic index, germination, GC content, recombination frequency), cell geometry (SA:V), and physiology study tools (cardiac output, stroke volume, pulse pressure, MAP, BMI, Mosteller BSA), plus doubling-time approximations—each on a single-intent URL. Chemistry, Physics, and Healthcare ops live on their own hubs.
Run introductory biology study math in one place: population growth %, crude birth and death rates, rate of natural increase, allele frequency, Hardy–Weinberg p²/2pq/q², mitotic index %, germination %, GC content, recombination frequency, surface-area-to-volume ratio, cardiac output and stroke volume, pulse pressure, MAP, BMI, Mosteller BSA, and population doubling time (rule of 70). Keep population, allele, base-count, and unit definitions identical across inputs. Chemistry, Physics, and Healthcare operations live on their hubs—physiology and BSA pages are educational formulas, not medical diagnosis or dosing.
Key facts
| Primary audience | Students, tutors, and teachers working introductory biology problems |
|---|---|
| Core formulas | Growth %, CBR/CDR/RNI, allele freq, p²/2pq/q², mitotic/germination/GC/RF %, SA:V, CO/SV, PP/MAP, BMI, BSA, rule of 70 |
| Category | Biology study / homework / lab |
| Related hubs | Chemistry; Physics; Healthcare (ops KPIs, not clinical physiology advice) |
Definitions
Rate of natural increase
Crude birth rate minus crude death rate on the same per-1,000 base.
Hardy–Weinberg genotypes
Expected shares p², 2pq, and q² under HW assumptions when p + q = 1.
Recombination frequency
Recombinant offspring ÷ total offspring × 100 (introductory linkage mapping).
Mosteller BSA
√((height_cm × weight_kg) ÷ 3600), reported in m² for study problems.
Formulas
- Population growth %: (End − Start) ÷ Start × 100
- Crude birth rate: (Births ÷ Population) × 1000
- Crude death rate: (Deaths ÷ Population) × 1000
- Rate of natural increase: CBR − CDR
- Allele frequency: Allele copies ÷ Total alleles
- HW p²: p × p
- HW heterozygote: 2 × p × q
- HW q²: q × q
- Mitotic index %: Mitotic cells ÷ Total cells × 100
- Germination %: Germinated ÷ Total seeds × 100
- GC content %: (G + C) ÷ (A + T + G + C) × 100
- Recombination frequency %: Recombinants ÷ Total × 100
- SA:V: Surface area ÷ Volume
- Cardiac output: Heart rate × Stroke volume
- Stroke volume from CO: CO ÷ HR
- Pulse pressure: SBP − DBP
- MAP: DBP + (SBP − DBP) ÷ 3
- BMI: Mass (kg) ÷ Height (m)²
- BSA (Mosteller): √((height_cm × weight_kg) ÷ 3600)
- Doubling time: 70 ÷ Growth %
Comparison table
| Topic | Guidance |
|---|---|
| Growth % vs crude birth rate | Growth % is (end−start)÷start; birth rate is births per 1,000. |
| RNI vs growth % | RNI is CBR − CDR; growth % uses start/end counts. |
| Birth rate vs death rate | Same per-1,000 shape; different numerator events. |
| Allele frequency vs p²/2pq/q² | p (or q) is allele share; genotype expectations use p², 2pq, q². |
| p² vs 2pq vs q² | Dominant homozygote, heterozygote, and recessive homozygote shares under HW. |
| Mitotic index vs germination % | Cell-count share vs seed-viability share. |
| GC % vs recombination % | Base composition vs recombinant offspring share. |
| SA:V vs BMI/BSA | Geometry exchange ratio vs anthropometric study indexes. |
| CO vs SV from CO | CO = HR × SV; SV tool divides CO by HR. |
| Pulse pressure vs MAP | SBP − DBP vs DBP + (SBP − DBP)/3. |
| BMI vs Mosteller BSA | kg÷m² vs √((cm×kg)/3600). |
| Doubling time vs growth % | Rule of 70 needs a growth rate input; growth % needs start/end counts. |
| Biology physiology vs Healthcare tools | Physiology/BMI/BSA here are study math; Healthcare hub is ops KPIs—not clinical advice. |
Glossary references
Reinforce entities by pairing percent language with conversion pages when learners mix fractions, decimals, and ratios.
❓ Frequently Asked Questions
Are these medical or clinical tools?
No. They are educational biology study calculators. BMI, BSA, MAP, and cardiac-output pages are not diagnosis, dosing, or treatment advice.
How do growth %, birth rate, and RNI differ?
Growth % compares ending to starting population size. Crude birth rate is births per 1,000. RNI subtracts CDR from CBR on the same per-1,000 base.
What are p², 2pq, and q²?
Under Hardy–Weinberg assumptions with p + q = 1, they are expected dominant-homozygote, heterozygote, and recessive-homozygote frequencies.
What units does Mosteller BSA use?
Height in centimeters and mass in kilograms: BSA = √((cm × kg) ÷ 3600).
Is MAP the same as pulse pressure?
No. Pulse pressure is SBP − DBP. This hub’s MAP approximation is DBP + (SBP − DBP) ÷ 3.
What is the rule of 70?
Doubling time ≈ 70 ÷ percent growth rate per period—an approximation for constant growth.
Do these replace a lab notebook?
No. They compute transparent formulas from your inputs—procedures and accepted values remain authoritative.