Environmental physiology

Environmental physiology is the study of how plants and animals respond to their surroundings. It looks at how living things adapt to weather, soil conditions, light, temperature, and other natural factors to survive and grow well. Think of it as the science of adjustment – how organisms change their body functions to cope with their environment.

A perfect Nigerian example is the cassava plant. During the dry season in northern Nigeria, cassava adjusts by reducing water loss through its leaves and storing more starch in its roots. This adaptation helps it survive harsh conditions while still producing a good harvest for farmers. Environmental physiology explains why cassava thrives in Nigeria's varying climates better than some other crops.

When you study this topic, focus on understanding adaptation as a survival strategy, not just memorizing definitions.

Environmental physiology examines how plants and animals respond to changes in weather conditions like temperature, rainfall, humidity, and light. When these climatic factors change, organisms must adjust their physical functions or behaviors to survive. For instance, Nigerian cocoa plants in the southwest experience reduced pod formation during dry seasons because water stress limits their growth. Similarly, when temperatures drop unexpectedly, some crops like maize may experience poor germination. Animals also adapt—cattle in northern Nigeria grow thicker coats during harmattan winds. Understanding these responses helps farmers predict crop performance and plan irrigation or manage livestock appropriately. Climate variations directly affect photosynthesis rates, water uptake, reproduction, and overall productivity of both plants and animals.

Temperature is the measure of heat energy in the environment, and it directly affects how plants and animals grow and survive on farms. Every crop and livestock has an ideal temperature range where it performs best. For example, cocoa plants in Nigeria thrive in temperatures between 20-30°C, but if temperatures drop below 15°C or exceed 35°C, growth slows down and yields decrease significantly.

Temperature influences key biological processes like photosynthesis, respiration, and water absorption in plants. When it's too hot, animals lose appetite and produce less milk or meat. When it's too cold, seeds won't germinate properly. Farmers must understand their region's temperature patterns to choose appropriate crops and provide shelter for livestock during extreme weather conditions.

Relative humidity is simply the amount of water vapour present in the air compared to the maximum amount that air can hold at that particular temperature. Think of it as how "wet" or "dry" the air feels around us. When relative humidity is high, the air holds plenty of moisture, making sweating less effective because sweat cannot evaporate easily from our skin. This is why you feel sticky and uncomfortable during the rainy season in Lagos or Ibadan.

Conversely, when relative humidity is low, like during harmattan winds in northern Nigeria, water evaporates rapidly from soil and plants, causing severe drying out. Farmers must understand relative humidity because it directly affects crop growth, disease development, and irrigation needs. High humidity encourages fungal diseases in plants, while low humidity increases water stress and reduces yields.

Light significantly influences how farm animals grow, reproduce, and produce food. When animals receive adequate daylight or artificial lighting, their bodies respond positively. For example, laying hens produce more eggs when exposed to 14-16 hours of light daily because light stimulates hormones that control egg production. Similarly, dairy cows in well-lit environments show improved milk production compared to those in dim conditions. Light also affects growth rates in broiler chickens and reproductive cycles in breeding animals. The wavelength and intensity of light matter too—brighter conditions trigger better performance across most livestock. Nigerian poultry farmers who install electric lights in their coops during dry seasons often report higher egg yields than those relying on natural light alone. Understanding light's role helps farmers maximize productivity and profitability.