Introduction to Ecosystem
An ecosystem is a form of a biological community in which life sustains along with the non-living things. An ecosystem comprises of living and non-living elements. More simply, the ecosystem is the sum of living and non-living things. We can call the ecosystem conjunction of two worlds, the living world, and the non-living living world. This conjunction is aided by different relationships. These relationships often called cycles e.g. the nutrient cycle or the energy flow. Biologically, it is believed that life arose from non-living. There was a certain molecular combination that gave birth to a living system. Thus, the link between the biotic and abiotic world is undeniable. When it is observed with a higher point of view this relationship forms a community and this community is called an ecosystem.
Life cannot sustain without a constant flow of energy. For the cycle of life to persist the energy must keep entering into the domain of biotic components. The major way through which energy enters the domain is through the process of photosynthesis. The energy is provided by sunlight in the form of photons which are small particles belonging to the abiotic domain. These non-living particles stimulate the plants and provide the energy to carry out functions like glucogenesis. The plants grow and become a source of food i.e. energy for herbivores. The energy obtained by herbivores is converted into their body mass and it helps them carry out other life processes like reproduction.
The herbivores become a source of energy for the carnivores and omnivores. That is how the energy flows from the bottom level of plants to the higher levels of the food chain. And when a living organism dies it is decomposed by saprophytes. These convert the dead matter into nutrients and energy. Which then aids the growth of plants. That is how the nutrients and energy keep moving in the ecosystem and sustaining the biological community.
Ecosystems are governed by factors. These factors are divided into external and internal factors. These factors include climate, soil textures, composition, the kinds of species, and the competition or succession among them. Ecosystems are versatile, they are ever-changing. They face rises and falls. They are also affected by the feedback loop system. Furthermore, ecosystems are also based on input and output systems. The ecosystem is a self-sufficient system. But when the output it provides is consumed by people and exceeds a limit it gets dependent on external resources or else it suffers.
The history of the Ecosystem
The word ecosystem was first coined by Arthur Tansley in 1935. In his studies, he emphasized the relationship between the organism and its environment. The environment contains abiotic components which can be organic or inorganic, but they are either produced by the organisms or absorbed by the organisms to sustain. Howard T. Odum and Eugene P. Odum were the ecologists that established a systemic approach to study the relationship between organisms and their environments. This gave birth to new ideas like the nutrient cycle and the flow of energy. The extensive study of ecosystems, relationships between organisms and their environments, the flow of energy in the food chain, and the nutrient cycle is called ecology.
Processes occurring in an Ecosystem
As described earlier, an ecosystem is governed by two types of factors
1. External factors
2. Internal factors
External factors
These are the factors on which the ecosystem depends, but these are themselves are independent factors. They make the basis of the layout of an ecosystem. These are known as state factors. They include topography and climate. A climate grows according to its geographical location and the effect an ecosystem causes on a geographical location takes a lot of time to become noticeable and sometimes it is negligible. Similarly, the climate plays an important role too. An ecosystem grows and nurtures according to the climate. It inhabited by only those species which are favored by the climate. For example, climate changes not only affect animals but also alters the process of photosynthesis by causing fluctuations in the rate. This particular pattern shapes an ecosystem. The quality and composition of the soil is also an undeniable factor. The soil quality is usually about the fertility of the soil. If the soil is fertile, this means it is rich in nutrients that are required by the particular type of flora. Thus, it will enhance and favors its growth. As some plant species require more trace minerals as compare to others. So, if the soil is rich in minerals it will promote the growth of the flora which further strengthens the fauna.
Internal factors
these are those factors that govern an ecosystem and also the ecosystem is governed by them. They make a feedback loop system. These factors include the population of saprophytes (which decompose dead material and release nutrients into the ecosystem). If an ecosystem is rich in biotic components it will surely have a higher number of organisms dying per unit. This will increase the population of saprophytes. As a result, the nutrient cycle will be improved. There are also internal factors like root competition. When there is the enrichment of nutrients the flora population will increase. Due to an increase in the population of plants, there will be a competition among roots to reach the direct source of water and nutrients. This competition also involves the formation of a symbiotic relationship with bacteria ( the nitrogen fixers) to survive. The kind of species that are present in an ecosystem also governs an ecosystem and the type of species present are also governed by the situation of the ecosystem. As some situations favor some particular species. This pattern affects all the inhabitants of the ecosystem as it causes a fluctuation in the food chain. Some other factors involve disturbances and successions in the ecosystem.
Primary production
Primary production means how much plants produce through photosynthesis. As it is the first phase, in which energy enters the biotic system. Through photosynthesis, plants produce organic matter through the process of utilization of inorganic minerals. The production done by plants through the process of photosynthesis is called gross primary production or GPP. This is the production of carbohydrates by the formation of water and oxygen and the complex mechanism through which carbon dioxide is used. Carbon is the key element of energy flow in the whole process as it is not found in every organism either alive or dead. Plants use about 50% of Gross Primary Production in the process of cellular respiration to produce energy to sustain itself. The left energy is called net primary production or NPP.
The amount of energy produced also depends on the rate of photosynthesis. It depends on a lot of factors. For example, the enzymes which are involved in photosynthesis are most efficient at a specific temperature. So, if the climate is extremely hot the rate of photosynthesis declines. The same thing happens in case of low temperature. Other factors that effects photosynthesis are the availability of water, the amount of light absorbed per unit area of the leaf, and the strength of chlorophyll in the leaves. All these factors which affect photosynthesis indirectly affect the gross primary production and net primary production.
The Energy Flow in an Ecosystem
With the knowledge briefed earlier, it is clear that energy enters an ecosystem through photosynthesis. This also makes it clear that all ecosystems must have some organisms which are capable of doing photosynthesis to bring energy into the biotic domain. They can be plants, photosynthetic algae, or photosynthetic bacteria. Another thing is which moves along the flow of energy and is very close to photosynthesis is Carbon. It also enters the biotic domain when plants utilize carbon dioxide during photosynthesis and produce carbohydrates like glucose. Energy and carbon are the basic blocks which when incorporates into the living organisms are known as primary production. The plants then become a source of food for the animals (herbivores), i.e. providing them with energy. The herbivores then become food for the carnivores. There is a constant flow of energy that can be observed in the food chain. With every step in the food chain, there is a loss of energy. The net primary production keeps on decreasing by each step. It gets stuck in the system in the form of dead organisms. Then come the saprophytes or decomposers to play their role. These organisms feed on the dead matter of the ecosystem and release energy and nutrients back into the environment. In this way, they minimize biological entropy. However, to study the energy flow in an ecosystem is not easy. As many organisms consume different types of food. And there are different classes of organisms at every step. The ones that produce food at the most basic level are called producers, for example, plants. Then the herbivores which feed on the plants are called primary consumers. After them, some animals feed on these herbivores and those are called secondary consumers. The chain gets diverse and complex and we introduce tertiary consumers.
Decomposition
This is the process that is exhibited by certain organisms. These are also called saprophytes or saprotrophs. These include bacteria, fungi, and some plants too which feed on the decaying matter of the ecosystem. Which is also called as detritus. The process of decomposition in an ecosystem usually takes place in three phases. The first one is the leaching phase, in this water takes away the components which are soluble in water. These water-soluble substances incorporate into the soil. The second phase is the breakdown phase in which the bacteria or other microbes physically breakdown the dead matter so that the next phase becomes easy to execute. The third phase is chemical alteration or decomposition. Decomposers also can produce secretions like catabolic enzymes which breakdown the dead matter into nutrients. Then the producers take up the broken matter and use it for their purpose.
Effect of Human Activities on the Ecosystem
With the advancement in every field, human interaction and its impact on any ecosystem have become inevitable. Every ecosystem provides a unique set of outputs or services. These services include timber, medicinal plants, food, fiber for textile, and other things which are required by human beings. It has always been the nature of humankind to gain without giving. If it does not get any input, it will surely fail to provide and any kind of output or service. Many threats are posed by human activities to natural ecosystems. These include the extinction of animals due to hunting, pollution, or destruction of natural habitat. To protect our interests and future interests we must learn to protect ecosystems. We should also learn how to make improve them, and how to help them achieve balance after destruction. Several organizations are promoting this cause.
Summary
An ecosystem is like a colony that is formed by living and non-living things. The biotic and abiotic domains both play a role in sustaining an ecosystem. In every ecosystem, the organisms which are capable of photosynthesis bring in energy and they are called producers. However, this energy is transferred to other organisms which are called consumers. When they die, they are decomposed, and the nutrients are released into the soil which is utilized by producers to grow and sustain so they may bring the energy again into the system. An ecosystem is governed by factors like soil composition, geographical location, topography, and climate. With modernization, human beings have become part of almost every ecosystem. There is almost no ecosystem that has not been affected by human beings. An ecosystem is based on input and output mechanisms. The outputs are usually services that are provided by an ecosystem. These services include wood, food, drugs, and many more. To keep getting these services we must learn to respect the integrity of all ecosystems rather than exploiting them for our gains or in the end we will suffer tremendous consequences. And many of these have started to appear in various forms.
Frequently Asked Questions
What is an ecosystem?
An ecosystem is an area in the biosphere where living and non-living matter interacts with each other to form and sustain life. The ecosystem consists of animals, plants, and other living organisms in a place along with non-living objects such as food, water, etc. in a particular area.
What are the 4 types of ecosystems?
The 4 types of ecosystems include forest ecosystem, freshwater ecosystem, marine ecosystem, and desert ecosystem.
What is a natural ecosystem?
A natural ecosystem is one that came into existence due to natural interaction between living organisms and non-living factors present in a particular place. It is not a man-made ecosystem.
What are the functions of an ecosystem?
Various ecosystems on this planet function to sustain life by exchanging water, energy and nutrients in a food chain. It is via an ecosystem that living organisms interact with environmental factors to make life possible.
References
- Tansley (1934); Molles (1999), p. 482; Chapin et al. (2002), p. 380; Schulze et al. (2005); p. 400; Gurevitch et al. (2006), p. 522; Smith & Smith 2012, p. G-5
- Odum, Eugene P (1971). Fundamentals of Ecology (third ed.). New York: Saunders. ISBN 978-0-534-42066-6
- Tansley, A.G. (1939). The British Islands and Their Vegetation. Cambridge University Press.
- Simberloff, Daniel; Martin, Jean-Louis; Genovesi, Piero; Maris, Virginie; Wardle, David A.; Aronson, James; Courchamp, Franck; Galil, Bella; García-Berthou, Emili (2013). “Impacts of biological invasions: what’s what and the way forward”. Trends in Ecology & Evolution. 28(1): 58–66. doi:10.1016/j.tree.2012.07.013. hdl:10261/67376. ISSN 0169-5347. PMID 22889499.