LESSON 4: Elements that support life – earth, water, wind, fire… (Abiotic)


Environmental Education School Curriculum Outcomes mention

ed in this lesson: Grade 1; Grade 2; Grade 3; Grade 4; Grade 5; Grade 6; Grade 7; Grade 8; Grade 9; Grade 10; Grade 11; Grade 12

Eco-Assignments that relate to content covered in this lesson: Grade 1; Grade 2; Grade 3; Grade 4; Grade 5; Grade 6; Grade 7; Grade 8; Grade 9; Grade 10; Grade 11; Grade 12

Now that we are aware that the natural environment is under threat mainly because of human-induced actions, we can begin to adapt our behaviour towards environmentally friendly sustainable living. However if we know a little more of how the natural environment functions, we will be able to act responsibly because we understand the results of our actions. Therefore we will now look at the different components of the environment – (the living and non-living in lesson 4 and 5) and then explore the functional relationship between these components (Lesson 6 and 7). The only way we are going to make an environmentally sound impact is when we understand what we are fighting for.

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. By the 1950’s (Supporting article D) these terms have become common concepts. But it must be noted that long before Tansley, people were aware of the close relationship between living and non-living components in the environment. During these ‘formative’ years of environmental studies, ecologists already identified and gave names to the various dynamics involved. They have identified and given names to different types of habitats with their various animals and plant material and the interrelationships between various organisms within these habitats (Supporting article O).

The zone of 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 grow and animals live and where we as humans must make a living.

Here the natural environment regulates itself within the limits of various structures that all relate to each other. These structures range from the biosphere, communities, species, populations and organisms. Within these structures there is an inter-connection from micro-organisms right up to huge predators. But because the earth is such a huge entity with so many interrelated elements, no one can fully comprehend the intricate relationships that exist. This is why scientists have subdivided the earth into smaller and simpler areas, called ecosystems. An 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. Various types ecosystems exist. On the continents there are forest-, meadow-, savanna- agricultural-ecosystems, and so forth. In and around inland waters we find lentic ecosystems such as lakes and ponds or lotic ecosystems such as rivers. The ocean is the biggest ecosystem of them all incorporating many smaller ecosystems like mangrove forests and corral reefs.

So, many ecosystems exist on  earth and they vary greatly in size and numbers and in complexity. Some parts of the earth are 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. Those areas in the biosphere where life 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).

We will now look at the existence and functioning of various interrelated building blocks of the ecosystem (Supporting article C) as it applies to the non-living components. In the next lesson 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 the content of the forthcoming discussions. We should remember that the elements of the ecosystem (biotic and abiotic) are actively interacting with each other – and are not stable inactive blocks such as bricks in a wall. To get a good overview of biotic elements refer to (Supporting article U).

The natural world functions as a  system where everything is connected to its surroundings in some way. Here nothing exists or functions on its own. As soon as any component is separated from other elements, it stops to function. Therefore any influence on one component is bound to have a ripple-effect throughout the system on all other components that are directly or indirectly attached to it (Supporting Article A). You can compare it to a “Tumbling Tower” game where each player in the circle gets a chance to remove a single block from the stack of blocks. At some stage the once stable tower will give in and topple over. Nature also has an inherit stability that maintains itself against interference from outside. This is called the resilience of an ecosystem. But once this resilience is stretched too far, it will collapse and will not be able to re-establish itself again. In the last lesson we will discuss the terms positive and negative feedback in this context.

The basic components in the ecosystem are referred to as organic and inorganic components or living and non-living components. The biotic sector consist of plants, animals and humans. The non-living or abiotic components are light, water, temperature, atmosphere, wind and soil, the earth’s crust with its associated rock types, topography and land-forms, fire and nutrients.

The environment functions not just as a static collection of blocks, but as an engine with interactive parts. So what drives this ‘engin’? All the activities taking place in and between organic and inorganic components are driven by light or energy that comes from the sun – the first abiotc factor. Green plants absorb and make the energy from the sun available to plant-eating organisms (like humans and animals) through the process of photosynthesis (Supporting article T).

Some living organisms are directly dependent on the sun for body temperature while others, for example, can regulate their own temperature through metabolism and sweat. Some plants and animals have a very low tolerance for temperature change. Plants like apple trees even need a certain intensity of cold temperatures to produce crops. Many animals (such as cold-blooded snakes and lizards) can only function effectively if the environmental temperature is increasing.

Because of the angle at which the sun hits the earth, there is an impact on vegetation. The equator receives more direct light from the sun than the polar caps enabling more life to survive in this region of the globe. Vegetation again influences the soil forming processes. 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. Far from being a stagnant component of the environment, land-forms form part of a dynamic system. Land-forms and topography has a direct influence on the soil, vegetation, animal life and even even human occupation.

Land-forms and topography can also have a major impact on the weather of a region. For example, the soaring peaks of South Africa’s Drakensberg mountain range intercepts the clouds dragging rain up from the subtropical Indian Ocean coastline. The pristine grassy uplands then funnel the rain steadily downwards in a series of clear streams feeding the east-flowing Tugela and Umzimvubu rivers, as well as South Africa’s mother river, the Orange, which flows west. On this way the mountain range further separate the well watered Indian Ocean coast from the dryer, harsher interior.

The role of the atmosphere and air movement (or wind) also play a crucial role to sustain ecosystems. We cannot breathe without oxygen in the 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. It is only the amount of water vapour 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. Furthermore wind is also necessary for the pollination of plants through seed dispersal.

The amount of water (another abiotic component) available also determines to a large extent the type and amount of vegetation and the amount of associated animal life. Compare for example a rainy tropical forest with a dry desert. In nature the plants and animal life are adapted to the environmental conditions in which they live.

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 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 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 without periodic veld fires. Humans often set fires deliberately to modify or change the environment for their own ends and most often this will have an adverse effect on the natural ecosystem. 

Multiple a-biotic components often interact to achieve certain results. The interactive effects of temperature, wind and rain on rocks are 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 such as earth worms and micro-organisms. In itself soil is highly complicated ecosystem. Healthy soil is very important to us. Not only do plants anchor themselves in soils, but it contains moisture and nutrients necessary for plants and micro-organisms to thrive in.

To close this lesson, underground rock also host fossil resources. In prehistoric times plant and animal material (latent energy) had been fossilised in the form of coal, oil or gas. These huge amounts of this energy are today extracted and applied to various industrial processes to maintain our present pace of progress. However, the byproducts generated by producing these huge amounts of energy have many negative implications for the health of the rest of the environment (Supporting article Q). The air is being polluted with an overabundance of CO2, methane, other harmful gasses and lead particles. This polluting finds its way into water systems and into the soil – from where it prevents the proper functioning of plants, animals and humans (Supporting article H). The environmental crisis could therefore be referred to as an ‘energy crises’. As we are now aware of the negative impact that the usage of fossil fuels has on our life-sustaining environment, it is high time to implement the alternative environmentally-friendly energy resources (Supporting article R) already developed.

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 realise 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 quality of the natural environment (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).

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 were able to find out how they contribute to our own well-being (Supporting article M). Even whole ecosystems are at risk (Supporting article B). Because of our behaviour many of the building blocks of ecosystems are being destroyed (Supporting article P and Supporting article L) and our very own existence is on the line.

“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 —