1. Temperature
There are large differences in temperature across earth’s surface due to variation in the quantity of incoming radiation. The unequal distribution of land and sea since the land is subject to a greater temperature range than the ocean. There is seasonal variability in light and temperature conditions due to aspect and topography (altitude). Temperature provides the medium in which chemical reactions and metabolic activities are enacted. Most chemical reactions increase in speed with temperature; thus in areas with extreme temperature conditions, such as very high and very low temperatures, the species decrease in number and variability. For instance as temperature decreases with increasing latitude, the species decrease. In plants, temperature affects the chemical breakdown. For each plant species, there is a minimum and a maximum temperature below and above which chemical reactions cannot take place. There is an optimum temperature (ideal) within which the species have the highest species. Variations in absolute temperature, which influence the physiological functions of plants and animals, are in most cases a result of latitude, altitude and distance from sea. In the tropics, the effect of temperature is of little significance in the distribution of organisms. Most places have high enough temperature. The effect of temperature is best demonstrated in vegetation zonation on mountain areas.
Temperature may influence in life through water availability. High temperature, characteristic of dry regions amounts to increase of water stress. Only organisms that are adapted to such conditions can survive in such environment. Extremely low temperatures are an environment hazard especially in the tropics because it leads to frost formation. Tropical plants have no bracts and stipulates to protect them against frost.
Otherwise, the effect of temperature is best demonstrated by high latitude plants, which become dormant during the low temperatures of winter and active during high temperatures of summer. On the average, life processes are best in the temperature range of 4 0 C to 40 0 C a few organisms however, in India, can survive in temperatures below 0 0 C. The effects of temperature are also tied up with those of light. Physiological processes depend upon intensity of light and temperature conditions. Plants for example, have their own optimum in high temperature conditions where they function freely. Processes like photosynthesis depend upon light intensity. The latter is a function of characteristic insulation. In high latitudes, these components affect life processes such as plant growth and flowering.
Correlations may provide only circumstantial evidence and do not necessarily indicate direct causal relationships. The species may be limited not by their inability to tolerate low temperatures, but by competition from other species that are superior competitors in cold climates.
2. Moisture
Moisture is vital in the maintenance of many physiological and chemical processes within plants and animals. There is a zone of high precipitation at equator. Ocean land configuration affects precipitation values: areas far from oceanic moisture are more drier than those, which are Maritime. Biogeographically, what is important is not so much the absolute amount of water, but rather the relationship between the two variables, precipitation and evaporation. It is possible to classify ecosystems according to their moisture relations. Hydrophytes: are plants, which require permanently moist, water logged or even aquatic conditions. Xerophytes are plants adapted to very dry conditions (characteristics of xerophytes cactus, euphorbia, prickly pear, reduction in leaf size, rolled or folded leaves to reduce surface area, hence evaporation, emphasis on growth below ground). Mesophytes are plant species, which are found, on sites with moderate soil moisture levels. Trophophytes: have organisms with which to avoid drought - e.g. long roots. The amount and distribution of rainfall is very important for plant life, and hence animal population. Forest communities characterize sufficient and welldistributed rainfall while tropical savannas characterize light seasonally distributed rainfall. Fauna population in the tropical savannas has to be equipped with certain animal mechanisms. The wildebeest of East Africa, for example are tuned to migrate from Serengeti in Maasai Mara during dry season to avoid competition for food. The problem of water stress for plants is averted by adaptation, which includes the development of thick bark, the shedding of leaves and the replacement of leaves by thorny structures. Water is very important for various physical processes such as
photosynthesis and respiration.
3. Solar radiation
Light and temperature are controlled by the latitude through inclination of the sun, the albedo of surface bodies, especially at the local level and aspect. The quantity rather than quality of light is very important in determining the distribution of living organisms. Wavelengths such as ultraviolet and gamma rays are known to affect regions of high altitudes. The plant characteristics that may be observed at 1500m and above in East Africa are a result of high component of ultraviolet light.
The components of a plant association depend on the amount of light received. At the regional scale, equatorial forests have high density compared to temperate or coniferous orests because of their unlimited supplies of energy. Locally, components of a stand of plants are dictated by differences in energy demands. At the lowest levels are the shade tolerant or low light species while at the top canopy are the light lovers or shade intolerants. Accordingly, light amount determines the abundance and diversity of species and their structural variation.
Solar radiation is the fundamental basis of photosynthesis and in the absence of light, even when it is in poor supply as on the floor of a dense forest, the number of species is restricted. Short wave solar radiation reaching the not only determines gross patterns of energy exchange within the biosphere, but certain of its components are also responsible on a more local scale for imposing limits to organic growth. The quantity and quality of light are important, together with the day length or photoperiod. Light varies both spatially and temporally. Spatially, there is variation due to latitude, thus the equator receives more light that the poles. These variations result in differences in the distribution and location of plant life. Light intensity is greatest at the equator. Quality of light varies according to the intercepting surface (vegetation canopies). Light is one of the main factors that determine shape, size of plants, suppression. Competition for light dominates the competition for plant survival. Root development and seedling development also determine the growth of plants. Photosynthesis depends on light variation. Competition for light by species decreases from the equator to the poles. Species adapt to stress conditions through mechanisms such as hibernation, reproduction, migration and feeding habits.
4. Wind
Wind is another climatic factor that affects life processes in different ways and modifies the hydrologic cycle by increasing the rate of evaporation. As a drying power, wind lowers the relative humidity in the vicinity of the leaf surface by removing water vapour. This leads to the creation of a vapour gradient there initiating evaporation in plants. As desiccation increases, the mesophytes are replaced by the xerophytes.
Wind affects coastal areas. It may lead to total or partial destruction of plants. Strong winds are experienced several times during the year in different parts of the country, and are associated with uprooting of trees, tree falls and broken branches. The high latitude and desert areas, there appears low and deformed growth. Wind equipped with particulate is associated with wind training; a process, which hits plants growth at a certain level, especially where wind direction is constant. All branches except those in the leeward side are destroyed. The effect of wind on the plant community depends on the depth of the roots,
wind velocity and frequency of occurrence. Frequent winds in high altitudes are partly accountable for dwarfness in trees.
Wind retards growth by increasing physiological stress on mating cells. In the seacoast dwarfness results from unfavourable internal water conditions, which is aggravated by salt sprays dispersed by wind. The effects of wind on the migration of birds and even of water plants is very interesting but not yet studied properly. Wind facilitates movement and increases the organism’s chance of arrival at a new site. Wind can affect plants through soil structure. Frequent wind activities in coastal and desert sand dunes bring about drifts of sand in sites devoid of vegetation. Such unstable sites hamper progressive succession of even simple life forms.
francis1897 answered the question on October 11, 2022 at 05:52