Now that we are aware that the natural environment is under threat mainly because of human-induced actions, we can begin to adapt our behavior towards environmentally friendly sustainable living. However if we understand a little more of how the natural environment functions, we would be able to act responsibly because we know. One of the main purposes of ECONATICS is to do just that and we will attempt this by looking at the different components of the environment (Lesson 4 and 5) and then by exploring the functional relationship between these components (Lesson 6 and 7).
The natural world functions as an interconnected system where every living thing is connected to its surroundings in some way. We call this the ecosystem. One can view the world as one big ecosystem with smaller overlapping ecosystems within this system. You can compare the natural system to a “Tumbling Tower
In this discussion we are going to talk about the existence and functioning of various interrelated building blocks within the ecosystem (Supporting article C), focusing particularly on the non-living components in the system. In the next issue we will deal with the living (biotic) components. Because of the interrelated nature of the ecosystem, some of the ‘supporting articles’ may therefore overlap with content of the forthcoming issue. We should remember that the elements of the ecosystem are actively interacting with each other – and are not stable inactive blocks such as the “Tumbling Tower
According to popular belief, the word ‘ecosystem’ was first used by the British ecologist Arthur Tansley in 1935. He identified the term biome as the entire complex of interacting organisms, both plants and animals (Supporting article W). He called the physical environment in which the biome exists, the habitat. Around the 1950’s (Supporting article D) these terms became common concepts. As it has long been realized that there exists a close relationship between living and non-living components in the environment, during these ‘formative’ years of official environmental studies, ecologists identified and gave names to the various dynamics involved. They not only gave names to the various dynamic units that exists such as different types of habitats with their various animals and plant material, but also identified the interrelationships between and within various organisms (Supporting article O).
In our Jenco-game, the more blocks we removed from the tower, the more unstable it became. In the same way the ecosystem will be increasingly unstable as individual elements are removed from it. A fundamental principle of nature is that nothing exits or functions on its own. As soon as anything is separated from other elements, it stops to function. Therefore any influence on one element is bound to have a ripple effect throughout the system on all other elements that are directly or indirectly attached to it (Supporting article A).
The natural environment encompasses various related concepts ranging from the biosphere, communities, species, populations, organisms with organs and organ systems and tissues made up of cells, cell-structures and atoms. But to be able to see and understand the full picture of these interrelationships from micro-organisms right up to huge predators is beyond our comprehension. Because the earth is such a huge entity with so many interrelated elements, no one can fully comprehend the intricate relationship that exists. This is why scientists have subdivided the earth into smaller and simpler areas, called ecosystems. The ecosystem is a relatively independent functioning unit which can be of virtually any size: From a fishpond to a tropical forest like the Amazon Basin
The zone in the earth consisting of the lower atmosphere or air and the upper part of the earth surface (or soil) is called the biosphere. It is in this minute zone that vegetation grows and animals can live and where we as humans too must make a living. The ‘undisturbed’ functioning of ecosystems is and has been under threat for many years because of the human element (Supporting article I). For various reasons, ranging from a need for survival and comfort to a greed for more, we are failing to live in harmony with the natural elements surrounding us. I believe that if we realize the impact we have on our natural surroundings, we might start behaving in a more responsible manner, especially knowing that our quality of life is directly related to the natural environment we find ourselves in (Supporting article F). When the majority of us share this knowledge passionately, more people will respond to pro-environmental initiatives striving to protect our natural heritage, like the international ‘Man and Biosphere Project’ (Supporting article K) or the local protection of our own Fynbos biome (Supporting article V)
As we mentioned, there exist many different ecosystems on earth and they vary greatly in size and numbers or in complexity. Some parts of earth is very inhospitable such as the Dead Sea , due to its exceptional salinity or the Polar caps where relatively little life is possible due to the cold conditions. But those areas in the biosphere where life however thrives are called the ecosphere. Yet, because of climate change the proper functioning of all ecosystems are under threat (Supporting article J). Ecosystems that are specifically vulnerable due to the human factor, are tropical forests (Supporting article E), and coastal ecosystems (Supporting article G).
The basic living components in the ecosphere are referred to as either biotic or a-biotic components. It could also be referred to as organic and inorganic components or living and non-living components. The biotic sector comprises plants, animals and humans. The non-living or a-biotic components are light, water, temperature, atmosphere, wind, and soil, the earth’s crust with its associated rock types, topography and landforms, fire and nutrients. Many of us take the a-biotic components for granted. For example we would be greatly concerned about the biotic components such as rhino’s being culled for their horns or whales for their oil or The Big Five being hunted just for the fun of it. Important as such animals rhinos and whales are to their respective ecosystems and to maintain a healthy biodiversity, without healthy a-biotic systems (air, water and soil quality for example), the biotic sector would not have a fighting chance to survive. That is why we will specifically focus on the role that a-biotic components play in the functioning of ecosystems today. Added to our discussion, we have included a very informative article on the a-biotic components and it will be worth your while to acquaint yourself with it (Supporting article U).
The environment thus functions not as a static “wall of bricks” but as an engine with interactive parts.
But what makes this engine “tick”? All the activities taking place in and between organic and inorganic components are driven by energy that basically comes from the sun. Green plants make the energy from the sun available to plant-eating organisms (like humans and animals) through the process of photosynthesis (Supporting article T). Because our great hunger for progress involves such huge amounts of energy – which can presently not be derived directly from the sun, but from limited fossil resources, the environmental crisis could be referred to as an ‘energy crisis’.
In pre-historic times plant and animal material had been fossilized in the form of coal. Huge amounts of energy are today extracted in the form of fossil fuels, but as you know, the processes involved in releasing these huge amounts of energy has many negative implications for the health of the rest of the environment (Supporting article Q). The air is being polluted and this polluting is filtering right through the ecosystem – it finds its way into water systems and into the soil – affecting plants, animals and humans (Supporting article H). The proper functioning of all life-sustaining ecosystems is adversely affected in this way. Now that we have realized the negative impact that the usage of fossil
fuels have had on our life-sustaining environment, it is high time to develop alternative environmentally-friendly energy resources (Supporting article R).
But before we get carried away with the degree of pollution taking place, let us for now limit ourselves to the proper functioning of ecosystems. Let us have a look at the importance of the sun as provider of energy to make life on earth possible. The sun is the original source of (approximately) all energy on earth (Supporting article S). Apart from energy via photosynthesis, the sun also provides us with other forms of energy such as light and heat. Both light and heat are essential a-biotic elements to maintain the ecosphere with its ecosystems. All plants need light to maintain their life processes. The most important is that of photosynthesis whereby food products are being produced by plants. In the absence of light this process cannot take place, for example in the depths of the ocean and in deep underground caves. The sequence of day and night - light and darkness – also plays an important role in growth of plants and animals. Even the length of days that is determined by the season, influences the production of crops.
The same goes for temperature. Some living organisms are directly dependent on the sun for body temperature while others can regulate their own temperature through metabolism and sweat for example. Most plants and animals have a very low tolerance for temperature change as well as temperature extremes. The temperatures of the air and the soil therefore have a definite influence on the distribution of life on earth. Some plants like apple trees even need a certain intensity of cold temperatures to produce crops. Many animals (such as cold-blooded snakes) can only function effectively if the environmental temperature is increasing.
The role of the atmosphere and air movement (or wind) also plays a crucial role to sustain ecosystems. We cannot breathe oxygen without air and plants cannot grow without carbon dioxide in the air. Drops of water in the form of rain cannot be formed without the process of condensation that happens in the air as moisture rises and becomes colder as the altitude increases. Carbon dioxide forms only 0.03% of the atmosphere, oxygen 21%, and nitrogen 78%. In spite of all the processes such as photosynthesis and respiration going on constantly, this composition of the atmosphere remains constant. This condition of balance is called dynamic equilibrium. It is only the amount of water vapor that varies from time to time and from place to place. The wind plays a vital role in moving air around and mixing it so that concentrations stay the same. Wind is also necessary for the pollination of plants through seed dispersal. Wind moves moisture over oceans so that rain can form.
Hot moisture rises with the air and form drops or condenses due to lowering of temperatures as it rises. For example in KwaZulu-Natal the moisture-laden winds blow over the warm waters of the Indian Ocean and rise over the Drakensberg. As it cools down over the high mountaintops it comes down as heavy rains.
Thus the a-biotic element called landforms is therefore also an important element in the environment. Apart from their role to act as ‘wind barriers’, northern facing slopes (in the southern hemisphere) are warmer than southern slopes because of the angle at which the sun hits the slope. This also has an impact on vegetation and vegetation influences the soil forming processes. Far from being a stagnant component of the environment landforms form part of a dynamic system. Slope elements such as cliffs, valleys, floodplains are all directly the result of interaction between movement in the crust of the earth, rock types and climate over long periods of time. Each of these landforms has a direct influence on the soil, vegetation, animal life and human occupation. For example a floodplain will typically have heavy clay soils, dense vegetation and humans can use it for agriculture.
The amount of water (another a-biotic component) available determines to a large extent the type and amount of vegetation and the amount of associated animal life. Compare for example a marshy area with a desert, or grassland with a tropical forest. Most of us in South Africa
Fire is also an a-biotic element playing a crucial role in various ecosystems. Caused by natural factors such as lightning, it is not necessarily harmful to the stability of an ecosystem as this only happens at random periodically. Many ecosystems have adapted to seasonal fires such as those that occur in the grassland regions of the world. Fire is actually a very important ecological factor in most terrestrial or land ecosystems. Fire reduces dead and dry organic matter to soluble compounds thereby releasing the phosphorus, calcium, potassium and other elements for rapid recycling, stimulating new growth. The seeds of some thorn trees are very hard and do not germinate easily. In these cases fire may be an advantage in the germination process. The fire lily of the Fynbos of the Cape does not flower effectively without periodic veldt fires. Humans often set fires deliberately to modify or change the environment for their own ends and often this will have an adverse effect on the natural ecosystem. Tropical forests, deserts and the arctic tundra are the only two ecosystems where fire caused by natural factors is rare.
Multiple elements often interact to achieve certain results. The interactive effects of temperature, wind and rain on the rocks of the earth is responsible for weathering, by which the element of soil is formed. We have classified soil as one of the a-biotic components of the environment, but this is not really true because soil does not consists only out of weathered rock. Soils have in it the ingredients of air, water, as well as organic material and millions of organisms; ranging from earth worms to mico-organisms. In itself soil is highly complicated ecosystem. It is hardly necessary to say that soil is very important to us. Not only do plants anchor themselves in soils, but it contains moisture and nutrients necessary for pants to thrive in. In the second series of ECONATICS, “The Human Impacts on the Ecosystem” we will look amongst others at three main a-biotic components namely soil, water and air, separately.
The Worldwide Fund for Nature (WWF) has stated that one of the main reasons for the continued
environmental deterioration is that people in general fail to recognize the value services that ecosystems provide to the human population (Supporting article N). Time is running out and because of the current trend of degradation of a-biotic elements, many species might disappear from the face of the earth as a result – long before we even got to know them or see how they contribute to our own well-being (Supporting article M). Even whole ecosystems are at risk (Supporting article B). We need to end this article in much the same fashion as previous ones: Because of our behavior many of the building blocks of ecosystems are being destroyed (Supporting article P and L) and our own existence is on the line.
