Plant and Animal Biology Applied to Agriculture
Domain focus
Plant and animal biology applied to agriculture tests how anatomy and physiology explain growth, reproduction, lactation, digestion and response to management.
Core rules
- Photosynthesis depends on light, CO2, water, chlorophyll and temperature; stomata balance CO2 uptake against water loss.
- Respiration releases energy from organic compounds; transpiration drives water and nutrient movement and cools leaves.
- Plant hormones control rooting, ripening, dormancy and tropisms; applied growth regulators must match dose and stage.
- Ruminants digest cellulose through rumen microbes, producing volatile fatty acids and microbial protein; monogastrics rely more on enzymatic digestion.
- Breeding and lactation depend on hormones, reproductive cycles, nutrition and body condition; stress can reduce fertility and immunity.
Worked example
In cattle, polled (P) is dominant to horned (p). Crossing two heterozygous polled animals, Pp × Pp, gives genotypes 1 PP : 2 Pp : 1 pp and phenotypes 3 polled : 1 horned. The reasoning is a Punnett square: each parent gives P or p with equal chance. The result is a probability for each calf, not a guarantee for a small herd; chance variation means a 3:1 ratio may not appear in a group of five calves.
Traps
Do not say plants "breathe" in the same way as animals. Do not confuse transpiration with translocation. In genetics, separate genotype from phenotype and do not treat predicted ratios as fixed outcomes. In ruminant nutrition, do not ignore microbial protein.