Important Terms and Concepts Associated with Environmental Physiology of Animals
Bioclimatology is the section of climatology which describes the association of climate with living organisms such as animals and plants.
Biometeorology is an interdisciplinary science studying the interactions between atmospheric processes and living organisms—plants, animals and humans.
Climate: The long-term (some 30 years) average condition of the meteorological variables in a given region. The periodic alterations of weather conditions such as temperature, wind, rain, snowfall, humidity and clouds in a broader locality moderated for years.
Weather: The short-term day-to-day fluctuations of the metrology variables, as distinguished from climate, which is the long-term manifestation of the weather.
Microclimate: The climate condition directly surrounding the animal.
Climate change: It refers to changes in measures of climate such as temperature and rainfall for a given area persisting for an extended period, typically decades or longer. Climate change can involve cooling or warming. Climate change may result from natural factors (e.g. changes in the sun’s energy, volcanic eruption), natural processes within the climate system (e.g. changes in ocean circulation) and human activities (e.g. burning of fossil fuels, agriculture).
Greenhouse effect: The greenhouse effect is the process by which radiative energy leaving a planetary surface, like the earth, is absorbed by some atmospheric gases, called greenhouse gases (GHGs). The GHGs transfer this energy to other components of the atmosphere, and it is re-emitted in all directions, including back down towards the surface.
Global warming: Global warming refers to an increase in average global temperature which in turn causes climate change solar radiation in the form of light waves passes through the atmosphere, most of this radiation is absorbed by the earth and radiated back into space in the form of infrared waves.
Part of the infrared waves is trapped by the atmosphere making the earth just warm enough to be livable. But because of too much GHGs that thicken the atmosphere, most if not all of the infrared waves are now trapped making the earth warmer.Basic Weather Parameters
Weather is referring to numerous elements of environment such as ambient temperature, atmospheric pressure, humidity, precipitation, solar radiation and wind which can be computed to evaluate the condition of atmosphere.
Animal Adaptation
Animal adaptation is the developmental changes that favour greater survival of an animal in its territory.
Adaptation (biological): The morphological, anatomical, physiological, biochemical and behavioural attributes that encourage the animal well-being and support its activity in distinct surroundings.
Adaptation (genetic): The genetical changes in the animal’s characteristics which benefits the persistence of a population in a specific environment. This may be established by developmental transformations over many generations (selected by nature) or inheriting definite genetic properties (selection by man).
Adaptation (physiological): The competence and mechanism of improvement of the animal to itself, to other living material and to its external physical environment.
Acclimatization: A long-term adaptive physiological modifications that enhanced the resistance to uninterrupted or frequent experience to complex climatic stressors (normally produced under field conditions). Acclimation represents the physiological or behavioural modifications that develop within the lifetime of an organism and which lessen or augment the resilience of a strain influenced by experimentally induced stressful changes specifically, climatic factors.
28.2.1 Natural Adaptation of Animals to Environment
Any animal cutting across species has their own inherent inability to cope with external environment. They acquire this potential from generation after generation in a specific environment which brings in alterations in both phenotypic and genotypic traits in these animals.
Through these several generational changes they acquire the capacity to live and produce maximum in a particular region.28.2.1.1 Morphological and Anatomical Adaptation
Morphological adaptation is a structural change which gives an animal a greater chance of survival in its habitat. Short and thin hair with light colour, light pigmented skin, large numbers of sweat glands, slender legs and less subcutaneous fat are the morphological adaptations in farm animals. Anatomical adaptations are the physical features of the animals which help them to survive in specific environment. The illustration of anatomical adaptations includes cat’s claw, rabbit’s back legs and shape of an animal.
28.2.1.2 Theories of Morphological Adaptation
Gloger’s (1833) ecogeographical rule refers animal colouration with climatic diversity. Skin pigments protect animals from UV radiation. Animals in cooler and dry regions have light-coloured skin while darker in high temperature and humidity. Bergman’s rule (1847) describes body size to in relation climate where, the animals at higher latitudes are larger and thicker in comparison to those near the equator for efficient conservation of heat. The heavy cattle breeds (Holstein) are well adapted to cooler temperature while smaller breeds (Jersey) prefer warmer. Wilson’s rule (1854) interrelates insulating capacity to climate, and animals in cold region have a dense, heavy, thick external coat, whereas those are in warm climate have short, glossy and thin hair. Allen’s rule (1877) interrelates animal appearance with temperature; animals living in cold zones have shorter extremities and bodily appendages than those in warm climate.
28.2.1.3 Characters of Well-Adapted Animals
Adaptations are any behavioural or physical characteristics of an animal that help it to survive in its environment. The modifications in body parts, body coverings and behaviours favour the survival of an animal to a specific environment. The better adaptive attributes to warm climates include a wide range of physiological functions, behavioural and morphological alterations.
On the physiological perspectives, the typical characteristics of well-adapted farm animals include their capability to cope with periodic water and feed scarcity. In addition, they have the ability to walk long distances in exploration of water and feed, digest low quality feeds, be resilient to heat stress and highly immune against ticks, and tick-borne diseases and other tropical diseases. The well adapted animals demostrate resilience behaviorally to graze without seeking shade, not reducing their feed intake, and drinking water at normal levels. Further, with increased standing time and rumination time as well these animals do not concentrate their urine and faeces. Morphologically, the well-adapted animals possess light/white and thin coat colour which will facilitate them to reflect solar radiation and induce effective evaporative cooling mechanisms.28.2.1.4 Energy Exchange Processes Between Animal and Environment
Animals interchange heat load with their immediate surroundings through conduction, convection, radiation and evaporation. These processes were described in subsequent subsections.
28.3