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It is an unmistakably clear fact that the natural environment is under threat mainly because of human-induced actions. Nature has developed perfectly balanced sustainable system which humans have distorted in the last few hundreds of years.
We need to change our behaviour in such a way that would benefit rather than harm the natural world. If we knew how the natural environment functions, we would be in a position to act responsibly because we then understand the impact of our actions on it.
In the following Chapters we would like to instil a basic understanding of the natural world by looking at the different interlinking components of the environment in Chapters 3 and 4; and then by exploring the (dynamic) functional relationship between these components in Chapters 5 and 6. In Chapter 7 we will apply sustainable principles on the urban environment as our habitat and consider a practical path towards Sustainability in Chapter 8.
Figure 3.1: Teenager, Greta Thunberg has initiated the “Fridays for Future” campaign for young people to resist environmental neglect and to protect the Earth
Figure 3.2: There exist an intricate relationship between living- and non-living components of an ecosystem.
The living or biotic components of ecosystems consist of 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, and finally fire and nutrients. There exists an interconnected functioning from micro-organisms up to big predators and humans.
But because the earth is such a large entity with so many interrelated elements, no one can fully comprehend the intricate relationshipsthat are at work. In an effort to identify distinctly different groups of components, scientists have subdivided the earth into identifiable functionally related units or areas, called ecosystems. Such an ecosystem can be as small and simple as a fishpond or as big and complex as to a tropical forest, depending on the scope of the study.
The environment however functions not just as a static collection of blocks, but like an engine with interactive parts. But what makes this engine “run”?
All the activities taking place in and between organic and inorganic components are driven by light, or energy that comes from the sun. This is our first abiotic component. Through the process of photosynthesis, green plants make energy from the sun available to plant-eating organisms like, bugs, grazing animals, and humans.
Some living organisms like cold-blooded lizards and snakes are directly dependent on the temperature from the sun for body heat. Warm-blooded animals like mammals are able to regulate their own temperature through bodily functions and sweat.
Some plants and animals have a very low tolerance for temperature change or temperature extremes. The temperatures of the air therefore have a definite influence on the distribution of life on earth. Some plants like apple trees even need a certain intensity of cold temperature to produce crops.
Figure3.4: The wind ensures the concentrations of gasses in the air remains the same.
Figure3.3: The natural world functions as an interconnected system, meaning that, should crucial components be removed, the whole ecosystem may crash.
The third abiotic component is the atmosphere and the movement of air, or wind. The wind plays a vital role in moving air around and mixing it so that concentrations of natural gasses in the atmosphere remains the same: carbon dioxide forms 0.03%, oxygen 21%, and nitrogen 78%. It is only the amount of water vapour that varies from time to time and from place to place. Despite all the processes such as photosynthesis and respiration going on constantly, this composition of the atmosphere remains constant thanks to the movement of air, or wind
Wind plays the dominant role in moving rain clouds (moisture) over oceans towards the continents. For example, along the coast of KwaZulu-Natal the winds that blow over the warm waters of the Indian Ocean are full of moisture when they rise over the slopes of the Drakensberg. As it cools down over the high mountaintops the water vapour condensates and comes down as rain. (Fig.3.6). This is the main reason for the lush vegetation of the ocean-facing slopes, compared to the drier conditions on the opposite side of the mountain range.
We can therefore identify landforms with their topography as the fourth abiotic component in ecosystems. Their orientation determines the angle at which the sun strikes the earth. North facing slopes will receive more direct insulation from the sun in the southern hemisphere.
Fig. 3.6 Orographic precipitation (Source: Wikipedia; Creative Commons)
Figure 3.5: The sun provides temperature, crucial for cold-blooded creatures like lizards.
This can be a determining factor in terms of soil temperature and the type and density of vegetation. Vegetation again influences the soil forming processes.
Slope elements such as cliffs, valleys, and 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. Far from being a stagnant component of the environment, landforms form part of a dynamic system. Landforms therefore have, via the soil, vegetation and animal life that they host, a direct influence on human land use.
All forms of life are dependent on water for their life processes. Water is the medium in which freshwater as well as marine communities exist. The availability of water determines to a large extent the type and amount of vegetation as well as the associated animal life. Compare for example the abundance of life forms in a marshy area with the scarcity of life-forms in a dry desert. A tropical forest also hosts a bigger number of life forms than a grassland.
The amount of water available for plants is dependent on many factors such as temperature, soil type, topography, etc. One of the largest problems facing terrestrial communities is the preservation and replenishment of the water supply in the body. The humidity of the air is also important for some forms of life. If the air is very dry, evaporation from the skin can be so great that the organism can die of dehydration. Many animals, like frogs, which are prone to dehydration, only come out at night when the relative humidity of the air is usually high.
Figure 3.7: The availability of water determines the amount of vegetation and associated animal life.
Figure 3.8: Fire is an essential abiotic element of nature
Fire (the sixth abiotic element) plays a crucial role in some ecosystems. It has always been a necessity in warming and cooking of food.
If caused by natural factors such as lightning, it is not necessarily harmful to the stability of an ecosystem as this only happens periodically. Many ecosystems have adapted to seasonal fires such as those that occur in the grassland regions of the world. Fire reduces dead and dry organic matter to soluble compounds and thereby releases elements such as phosphorus, calcium, and potassium for rapid recycling, stimulating new growth.
The seeds of some thorn trees are very hard and do not germinate easily. In these cases, exposure to fire helps in the germination process. The fire lily of the Fynbos in the Cape does not flower if there are not periodic veldt fires
Multiple abiotic components often interact to achieve certain outcomes. The interactive effects of temperature, wind, and rain on rocks are responsible for weathering, by which the seventh abiotic component namely soil, is formed. Soil is normally described as the uppermost weathered layer of the earth’s surface. It is the growth medium that supports almost all terrestrial plant and thus animal life. Although soil is one of the more permanent and less changeable components of the ecosystem, it nevertheless is easily damaged through incorrect use. Because of the permanent nature of soil, it is difficult to restore it to its prior condition once it has been damaged.
Figure 3.9: Fire can be devastating and take decades to recover
Figure 3.10: Fire in built-up areas however results in massive cost.
We usually classify soil as an abiotic component of the environment, but it does not consist only of weathered rock. It includes rock remnants, gases, water, dissolved inorganic salts, living organisms and their remains. It is home to two thirds of all living species on earth, including bugs, bacteria, fungus, and many other organisms. It thus consists of much more than weathered rock and could be classified as either biotic or abiotic part of the environment.
Humans depend totally on the abiotic elements of nature. But none of these can be utilized without energy. All activities require energy. This we basically access by means of the food that we eat. But, because of our insatiable hunger for progress we extract huge amounts of energy from limited fossil resources. Therefore the environmental crisis could be referred to as an ‘energy’ crisis.
In pre-historic times plant and animal material (latent energy) had been fossilized in the form of coal, oil, or gas deposits. Now these energy resources that had been accumulating over millions of years are being utilized rapidly by people across the globe for transport and the generation of electricity.
However, the by-products of these energy sources, have many negative impacts on the health of people and the rest of the environment. The air is being polluted with an overabundance of carbon-dioxide, methane, lead particles, and other harmful gases which also pollutes soil and water systems.
Figure 3.11: The energy we require for progress is currently mostly derived from coal.
All-in-all, it suppresses the proper functioning of ecosystems, creating unhealthy living conditions, and global warming that is changing the climate of the world. We know the negative impact that the usage of fossil fuels have on our life-sustaining environment. There are environmentally friendly energy alternatives already developed. For as long as we refuse to adjust our pace of development in line with our capacity to generate clean energy, we will remain on a downward spiral of environmental neglect and self-destruction.
Figure 3.12: Out arrogant attitude of being the dominant apex of nature must change from an EGO-mindset to one of merely being an ECO-sensitive link in the system of life.
The message is clear: because of our behaviour many of the building blocks of ecosystems are being jeopardized, and our very own existence is on the line. The sooner we learn and adapt to the directives of nature, the sooner we will be able to survive the looming environmental crisis.
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 of services that ecosystems provide to the human population. As “ecological dominant” we are exploiting these to the point of exhaustion for our own comfort instead of slotting in harmoniously as part of the system. We should not consider ourselves as more important than any specie and should not claim any special privileges. Nature is not just there for us. We are also a part of nature.
“When the animals come to us,
asking for our help,
will we know what they are saying?
When the plants speak to us
in their delicate language,
will we be able to answer them?
When the planet herself
sings to us in our dreams,
will we be able to wake ourselves, and act?”
— Gary Lawless
The new science of biomimicry teaches that humans should look at nature for directives in their technological development. “Nature knows best.
And the Bible also echoes…
“..ask the animals, and they will teach you,
or the birds in the sky, and they will tell you;
or speak to the earth, and it will teach you,
or let the fish in the sea inform you”.
(From the Bible: Job 12 v 7)
Figure 3.13: Ecosystems suffer as a result of unsustainable human-induced practices like the indiscriminate hunting of the scaly anteater.