What is an Ecosystem?
An ecosystem is a structural and functional unit of ecology in which species interact with one another and their surroundings. In other terms, an ecosystem consists of a series of interactions between species and their surroundings.
- Ecosystem was coined by the British ecologist A.G. Tansley (1953). It is the basic functional unit of ecology, consisting of the biotic community and its abiotic (nonliving) surroundings.
- Ecosystem is the functional unit of nature in which creatures interact with one another and their surroundings.
- Ecosystems are self-regulating and self-sustaining landscape units that can be either terrestrial or aquatic. Deserts, forests, and grasslands are examples of terrestrial ecosystems. Freshwater (ponds, lakes, streams) and saltwater (marine estuaries) aquatic habitats exist.
- Natural (forest, sea) or artificial (garden, aquarium, farm) ecosystems may evolve under natural or man-made conditions.
- Typically, an ecosystem is an open system due to the continual and varied input and loss of energy and substances. Ecosystem is also known as biogeocoenosis, geobiocoenosis, microcosm, ecosom, biosystem, etc., while the entire planet might be referred to as the biosphere or ecosphere.
- Ecosystem consists of a variety of interdependent abiotic (nonliving) and biotic (living) elements.
- Through nutrient cycles and energy transfers, these biotic and abiotic components are interconnected.
- Through photosynthesis, energy enters the system and is absorbed into plant tissue. By eating on plants and each other, animals play a crucial role in the transfer of matter and energy throughout the system.
- Additionally, they affect the amount of plant and microbial biomass present. By decomposing dead organic matter, decomposers return carbon to the environment and enhance nutrient cycling by turning nutrients held in dead biomass back into a form that plants and microorganisms can readily use.
- External and internal elements exert control over ecosystems. The overall structure of an ecosystem is determined by external elements such as climate, the parent material from which the soil is formed, and terrain, which are not directly controlled by the ecosystem.
- Decomposition, root competition, shade, disturbance, succession, and the sorts of species present all influence internal variables.
- While resource inputs are primarily governed by external processes, resource availability inside an ecosystem is governed by internal factors. Consequently, internal variables not only regulate environmental processes, but are also governed by them.
- Ecosystems are dynamic entities, as they are prone to periodic disturbances and are always recuperating from a previous disturbance.
- Resistance is the tendency of an ecosystem to remain near to its equilibrium state despite the disturbance.
- Ecological resilience is the capacity of a system to absorb disturbance and reorganise while experiencing change while retaining essentially the same function, structure, identity, and feedbacks.
- Ecosystems can be researched in a number of ways, including theoretical studies, studies monitoring individual ecosystems over extended periods of time, studies examining contrasts between ecosystems to explain how they function, and direct manipulation experiments. Biomes are broad groups or classes of ecosystems.
- There is no obvious distinction between biomes and ecosystems, though.
- Ecosystem classifications are special types of ecological classifications that take into account all four parts of the definition of ecosystems: a biotic component, an abiotic complex, their interactions and the physical space they occupy.
- People depend on a variety of commodities and services provided by ecosystems. The “physical, material products” of ecosystem activities, such as water, food, fuel, construction material, and medicinal plants, are referred to as ecosystem goods.
- In contrast, ecosystem services are typically “improvements in the condition or location of valuable goods.”
- These include the maintenance of hydrological cycles, the cleansing of air and water, the maintenance of atmospheric oxygen, crop pollination, and even beauty, inspiration, and research opportunities.
- Human influences such as soil loss, air and water pollution, habitat fragmentation, water diversion, fire suppression, and imported and invasive species affect numerous ecosystems. These dangers might result in either a sudden alteration of the ecosystem or a gradual disruption of biotic processes and deterioration of the ecosystem’s abiotic conditions.
- Once the original ecosystem has lost its distinguishing characteristics, it is deemed to have “collapsed.” Restoring ecosystems can help achieve the Sustainable Development Goals.
Characteristics of Ecosystem
According to Smith (1966), the following are the general characteristics of the ecosystem:
- It is a significant structural and functional unit in ecology.
- Its species diversity is proportional to its complexity; complex ecosystems have high species diversity and vice versa.
- Its role is connected to the circulation of energy and materials inside and throughout the system.
- The relative quantity of energy required to sustain an ecosystem is proportional to its structure. The greater the complexity of a building, the less energy it requires to maintain itself.
- It advances from less complicated to more complex states as it evolves. Early phases of each succession are characterised by an abundance of potential energy and a relatively high energy flow per unit of biomass. Later (mature) stages have less energy accumulation and a more varied energy flow.
- In each given ecosystem, both the environment and the energy fixation are restricted and cannot be exceeded without creating severe negative impacts.
- Changes in the environment impose selective pressures on populations, to which they must adapt. Those organisms incapable of adjusting to the altered environment must perish.
Structure and Function of Ecosystems
Organization of both biotic and abiotic components characterises the structure of an ecosystem. This covers the energy distribution in the environment. It also contains the prevailing climatic conditions in that environment. The structure of an ecosystem can be divided into two primary elements:
- Biotic Elements
- Abiotic Components
In an ecosystem, the biotic and abiotic components are interconnected. It is an open system in which energy and components are able to move freely across the boundaries.
1. Abiotic Components
- The non-living components of an ecosystem are abiotic.
- They have a substantial impact on the structure, distribution, behaviour, and interdependence of organisms.
- It consists of air, water, soil, minerals, sunlight, temperature, nutrients, wind, height, and turbidity, among other factors.
Types of Abiotic Components
Abiotic elements are primarily of three types:
- Physical or climatic components: Such include temperature, water, soil, light, relative humidity, and pressure.
- Inorganic compounds: In addition to water, minerals (such as sulphur, nitrogen, and phosphorus), and atmospheric gases (O2, N2, CO2 etc).
- Organic Compounds: Includes organic compounds contained in plant and animal corpses
Functions of Abiotic Components
The following are the functions of major abiotic component factors:
- Carbon and nitrogen exist in the atmosphere.
- The nutrients required by living organisms are derived from soil minerals and dissolved nutrients in water.
- Organic materials, including proteins, carbohydrates, lipids, and other complex molecules, serve as a link between the system’s biotic and abiotic components.
- The abiotic conditions in which organisms perform their biological processes are determined by climatic factors such as sun radiation and temperature.
- Soil is a medium for plant growth, consisting of a mixture of minerals and organic materials that can provide all of the required nutrients and water.
2. Biotic Components
- The term “biological components” refers to all living elements of an ecosystem.
- On the basis of their feeding, biotic components can be classified as autotrophs, heterotrophs, or saprotrophs (or decomposers).
Types of Biotic Components
According to their mechanism of nourishment, there are three categories of Biotic Components:
- Producers consist of all autotrophs, including plants.
- They are referred to as autotrophs since they can create food through photosynthesis.
- Therefore, all species higher up the food chain depend on producers for sustenance.
- Example: Green plants, tiny shrubs, fruit, phytoplankton, and algae are some examples.
- Consumers or heterotrophs are organisms that obtain their sustenance from other organisms.
- Primary consumers, secondary consumers, and tertiary consumers are further classifications of consumers.
- Primary consumers: Primary consumers are always herbivores since they obtain their food from producers. Additionally known as herbivores. They only consume primary producers, such as plants or algae. An Everglades grasshopper, for instance, is a major consumer. Other examples of primary consumers include white-tailed deer who feed on grassland grasses and zooplankton that ingest microscopic water algae. Example: Rabbits, bears, giraffes, flies, people, horses, and cows, are some examples.
- Secondary consumers: Primary consumers provide energy to secondary consumers. They may be carnivorous or omnivorous. Example: Some secondary consumers consume both plant and animal foods. They are referred to as omnivores, from the Latin for “eats everything.” A raccoon is an example of an omnivore, as it consumes plant matter such as berries and acorns, as well as crayfish, frogs, fish, and other small animals.
- Tertiary consumers: Tertiary consumers are creatures that obtain their sustenance from secondary consumers. Tertiary consumers might be herbivores, carnivores, or omnivores. Example: All large felines are tertiary consumers. For example, lions, tigers, pumas, jaguars, etc. In addition, they are apex predators, which means that no other organisms prey on them in their ecological environment.
- Quaternary consumers: There are quaternary consumers in some food chains. These organisms obtain energy by preying on tertiary consumers. Furthermore, as they have no natural predators, they are typically at the top of the food chain. Example: Quaternary consumers are often the apex predators in their own ecosystems, and they feed on tertiary consumers, which they ingest. As well as other huge predators, lions, wolves, polar bears, humans, and hawks are examples of quaternary consumers.
- Saprophytes such as fungi and bacteria are decomposers. They directly feed on decaying and decomposing organic substances. Decomposers are vital to the ecology because they recycle nutrients for reuse by plants.
- Example: Most decomposers are tiny organisms, including protozoa and bacteria. Other decomposers are visible without the use of a microscope. They consist of fungus and invertebrate animals known as detritivores, such as earthworms, termites, and millipedes.
Interactions Between Abiotic and Biotic
- Through nutrient cycles and energy flows, biotic and abiotic components interact as a system and are interconnected. For example, energy and nutrients enter the system via photoautotrophic organisms.
- They are photosynthesis-carrying creatures, such as plants and green algae. The heterotrophs, such as animals, then consume the photoautotrophs. This causes the energy and nutrients to circulate throughout the body.
- These creatures’ demise stimulates breakdown by decomposers. This process returns the nutrients to the environment so that organisms can reuse them. To learn more about this topic, please visit: The Ecosystem’s Processes
- The biotic and abiotic components may also function as environmental (ecological) elements that influence the ecosystem.
- biotic factors refer to the biotic components whose biological activity has an effect on the ecosystem.
- The abiotic factors consist of non-living organisms and the physical characteristics of an ecosystem, such as climate, temperature, and pH.
- The level of predation in an ecosystem is an example of a biotic factor. If the number of predators increases, predation activity is likely to increase as well. This, in turn, might dramatically reduce their prey’s population density.
- If their prey is a key species, meaning that another group of creatures relies on them for survival, then the decline (or worse, extinction) of these key species could also result in the decline (or worse, extinction) of the organisms that depend on them.
- As for abiotic factors, they can affect the population size or density of a species. For instance, acid rain, which is unusually acidic precipitation with large concentrations of hydrogen ions, can have negative effects on the soil (e.g., leaching) as well as on plants and aquatic creatures that are sensitive to low pH. Other abiotic variables besides pH include light, salinity, air, soil or substrate, and temperature.
Types of Ecosystem
An ecosystem might be as little as a desert oasis or as large as an ocean spanning thousands of kilometres. Three types of ecosystems exist:
- Natural: Land-based or Terrestrial, such as Forest, Grassland, and Desert, and Aquatic, such as Pond, Lake, Wetland, River, and Estuary. It is separated into two groups;
- Terrestrial Ecosystem
- Aquatic Ecosystem
- Artificially ecosystems: Crop fields and an aquarium are examples of ecosystems created by humans.
1. Terrestrial Ecosystem
- Terrestrial ecosystems are ecosystems that exist solely on land.
- Distinct types of terrestrial ecosystems are dispersed throughout various geological zones.
Types of Terrestrial Ecosystem
- Forest Ecosystem: A forest ecosystem consists of a variety of plants, especially trees, animals, and microorganisms that coexist with the environment’s abiotic elements. Forests aid in maintaining the earth’s temperature and are the primary carbon sink.
- Grassland Ecosystem: In a grassland habitat, grasses and plants dominate the vegetation. Examples of grassland ecosystems include temperate grasslands and tropical or savanna grasslands.
- Tundra Ecosystem: Tundra ecosystems lack trees and are located in frigid climes or regions with scant precipitation. These are snow-covered for the majority of the year. The Arctic and mountaintops are home to tundra-type ecosystems.
- Desert Ecosystem: Deserts can be found on every continent. These locations receive little precipitation and have scant vegetation. The days are warm, while the evenings are chilly.
2. Aquatic Ecosystem
- In contrast to terrestrial ecosystems, which are established on land, an aquatic environment is one that forms around a body of water.
- Aquatic ecosystems feature populations of creatures that are mutually and environmentally reliant.
- Marine and freshwater ecosystems are the two primary types of aquatic ecosystems.
- Freshwater environments can be lentic (including pools, ponds, and lakes), lotic (including streams and rivers), or wetland (areas where the soil is saturated or inundated for at least part of the time)
Types of Aquatic Ecosystem
These can be further classified into the following two categories:
- Freshwater Ecosystem: The freshwater environment consists of lakes, ponds, rivers, and streams, as well as wetlands. In contrast to marine ecology, these do not contain any salt. It is divided into 2 groups;
- Lotic: river, streams, etc.
- Lentic: Lake pond or swamp.
- Marine Ecosystem: The marine ecosystem consists of oceans and seas. Compared to the freshwater habitat, these have a higher salt concentration and a broader variety of organisms. There are various types of marine ecosystems:
- Shallow water – Some little fish and coral are exclusive to the shallow waters along the shore.
- Deep water – Ocean depths can support the existence of large and even colossal animals. Some of the world’s most bizarre species reside at the ocean floor.
- Warm water – Warmer waters, such as the Pacific Ocean, contain some of the world’s most spectacular and complex ecosystems.
- Cold water – Even though they are less diverse, frigid waters sustain relatively complex ecosystems. Plankton is typically at the bottom of the food chain, followed by little fish that are consumed by larger fish or by other animals like seals and penguins.
- An artificial ecosystem is a system that was created by humans and can be further categorized as terrestrial, freshwater, or marine.
- A terrarium is an example of an artificial ecosystem. Numerous man made habitats are constructed for conservation, beauty, and the study of biology and ecology.
Factors Of Ecosystem
- The sun is the primary energy source for all life on Earth. To produce food, green plants and photosynthetic bacteria require light. Animals rely on plants for nutrition.
- Intensity, quality, and duration of light have effects on living things. Intensity and quality of light influence photosynthesis, flowering, and germination in plants, and migration, hibernation, and reproduction in animals.
- A photographic light metre is used to measure the strength of light, whereas the seechi disc measures the light’s penetration into water.
- Biochemical processes of the majority of organisms function optimally within a small temperature range. Especially in hot deserts, seasonal, altitude, latitude, and diurnal variations affect temperature.
- Consequently, this influences the distribution of organisms within an environment. In terrestrial settings, temperature fluctuations have a greater effect on the dispersion of organisms than in aquatic habitats.
- To survive severe temperatures, living species must develop the physiological and behavioral adaptations necessary.
3. Atmospheric Pressure
- The weight of the atmosphere causes it to exert pressure on the ground. Atmospheric pressure on Earth’s surface varies with height.
- Variations in atmospheric pressure affect the amount of accessible oxygen for respiration and the amount of carbon (IV) oxide for photosynthesis. The dispersion of organisms is affected by the presence of these two gasses.
- It refers to the amount of atmospheric water vapour. When humidity is high, water vapour is abundant, and vice versa.
- Humidity influences the rate of water evaporation from the surface of organisms, such as transpiration and perspiration. This influences their distribution throughout the planet.
- A paper hydrometer or a wet and dry bulb hygrometer is used to measure humidity.
- Wind moves the air. It increases the pace at which organisms lose water, hence altering their distribution.
- Wind is also crucial to the creation of precipitation. Desert winds create sand dunes that can serve as habitats for other species.
- The development of waves by wind in lakes and oceans increases aeration in these bodies of water.
- In regions subjected to severe winds, tree development may be stunted and deformed.
- In addition to dispersing spores and seeds, the wind influences the movement and disposal of flying animals.
- In a habitat, the position of olfactory animals in relation to their prey is determined by the wind.
- A wind vane or windsock is utilised to determine the predominant wind direction.
- Anemometer is utilised to measure wind speed.
- It refers to the salt concentration of water, which distinguishes between marine, estuary, and fresh water environments.
- The problem of water loss from the body to the environment is exacerbated by saline conditions immediately around organisms. Only animals with the appropriate osmoregulation adaptations are able to inhabit such settings.
- Calculating the percentage of salts in water or using the acid-base titration method can be used to estimate salinity.
7. pH ( Hydrogen ion Concentration)
- pH measures the acidity or alkalinity of water in aquatic organisms or soil solutions. It effects plant and animal dispersal in soil and freshwater ponds. Some plants thrive in acidic environments, whereas others thrive in alkaline environments.
- Leaching nutrients or soil depletion can alter the pH level of a soil. Utilizing BDH universal indicator solution, paper, and a pH metre, the pH is expressed on the Ph scale.
Productivity in an Ecosystem
Productivity is the amount of biological matter produced per unit of time. It has the following varieties:
1. Primary productivity
- Green plants absorb solar energy and store it as chemical energy in an organic form.
- This constitutes the first and most fundamental form of energy storage, known as primary productivity.
- It is the rate at which photosynthesis produces organic matter per unit area of surface per unit time.
2. Secondary productivity
- It refers to heterotrophs or consumers.
- The food materials are utilised by the customers during respiration.
- The rate of food energy assimilation is known as secondary productivity.
3. Net productivity
- This refers to the pace at which non-heterotrophic organic matter is stored.
- These may be equivalent to net primary production minus heterotrophic consumption.
Important Ecological Concepts
1. Food Chain
- The sun is the earth’s primary source of energy. It supplies the necessary energy for all plant life. The plants use this energy for photosynthesis, the mechanism through which they create their food.
- During this biological process, light energy is transformed into chemical energy, which is then transmitted to successive trophic levels. The energy transfer from a producer to a consumer to an apex predator or detritivore is referred to as the food chain.
- Scavengers break down dead and rotting substances together with organic detritus into their component parts. These elements are then absorbed by the reducers. After obtaining energy, reducers release molecules back into the environment that can be reutilized by producers.
2. Ecological Pyramids
- Ecological pyramids are graphical representations of the number, energy, and biomass of an ecosystem’s ascending trophic levels. In 1927, Charles Elton was the first ecologist to explain the ecological pyramid’s principles.
- In the form of a pyramid, the biomass, quantity, and energy of organisms from the producer level to the consumer level are depicted; consequently, it is known as the ecological pyramid.
- The producers are at the base of the ecological pyramid, followed by primary and secondary consumers. The pinnacle is held by tertiary consumers. In certain food chains, quaternary consumers are at the very top.
- In general, producers are more numerous than primary consumers, and main consumers are more numerous than secondary consumers. And last, apex predators follow the same pattern as the other consumers, in that their numbers are significantly lower than those of the secondary consumers.
- For instance, grasshoppers graze on abundant crops such as cotton and wheat. The common mouse then preys on these grasshoppers, which are relatively less in number. Cobras and other serpents prey on the mice. The ultimate predators of snakes are apex predators such as the brown snake eagle.
Grasshopper →Mouse→ Cobra → Brown Snake Eagle
3. Food Web
- The food web is a linked network of food chains. It includes all food chains within a certain habitat.
- Understanding that plants are the foundation of all food chains is helpful. In marine ecosystems, phytoplankton serves as the principal producer.
Functions of Ecosystem
- It governs vital ecological processes, sustains life support systems, and provides stability.
- In addition, it is responsible for nutrition cycling between biotic and abiotic components.
- It keeps the various trophic levels in the ecosystem in balance.
- It circulates minerals within the biosphere.
- The abiotic components facilitate the energy-exchanging production of organic components.
Examples of Ecosystem
The following are examples of ecosystems discussed in this article:
- Ecosystem of deciduous woodland
- Savannah ecosystem
- Coral reef community
- Thermal springs ecosystem
Deciduous forest ecosystem
- A deciduous forest is characterised by trees that lose their leaves yearly and re-grow them at the beginning of the next growing season.
- As an adaptation to the cold season in temperate countries or the dry season in subtropical and tropical regions, they lose their leaves.
- Oaks, beeches, birches, chestnuts, aspens, elms, maples, and basswoods predominate at mid-latitudes.
- The dominating tree genus in the Southern Hemisphere is Nothofagus (southern beeches).
- Snakes, frogs, salamanders, turtles, nails, snails, insects, spiders, birds (such as warblers, owls, woodpeckers, hawks, etc.), and mammals are common animals (such as mice, moles, chipmunks, rabbits, weasels, foxes, and deer).
Coral reef ecosystem
- The coral reef is an ecosystem generated by corals that construct reefs.
- The reefs are comprised of colonies of coral polyps, such as stony corals, that live in clusters.
- They are one of the world’s most diversified ecosystems. As such, they are referred to as the oceanic rainforests.
- The majority of them inhabit shallow depths in tropical waters. The reefs are home to mollusks, worms, crabs, echinoderms, sponges, tunicates, and fish, among other species.
- Savannahs are a mixture of forest and prairie environments.
- The widely separated, dispersed canopy trees permit light to reach the ground. Because of this, grass-dominated shrub and herbaceous strata are also able to flourish.
- Consequently, grazers such as sheep, cattle, and goats are widely found in this region.
- Typically, this type of environment serves as a transition zone between forest and desert or grassland.
- Microecosystems are ecosystems confined to small or minute places and defined by unique environmental conditions. Let’s examine a tree’s environment.
- A tree generates a miniature ecosystem in which numerous species of organisms reside.
- A tree may house lichens and other epiphytes, invertebrates (such as insects), amphibians, and other animals.
- The epiphytes themselves provide a habitat for fungus, bacteria, and myxomycetes.
Hot spring ecosystem
- A hot spring is a spring whose water temperature is higher than the surrounding area.
- The water that emerges from the spring is heated geothermally, i.e. by the earth’s mantle heat. Due to the high temperature, this is one of the habitats with the fewest species of life.
- Thermophiles are creatures that survive between 45 and 80 °C (113 and 176 °F).
- These organisms include thermophilic amoeba (such as Naegleria fowleri and Acanthamoeba), thermophilic bacteria (such as Legionella), and diverse archaea.
What are Stratifications?
- Stratification is the occurrence of vertical zonation in an ecosystem and is indicative of the presence of favorable environmental circumstances; for instance, trees occupy the top vertical strata or layer of a forest, shrubs the second, and herbs and grasses the bottom levels.
- Stratification allows a vast number and variety of plants to coexist in the same place. It also provides microhabitats and niches for a variety of animal species.
- Where environmental circumstances are unfavorable, such as in desert habitats, there are few trees and bushes.
What is Standing crop?
- The amount of live biomass in an ecosystem is its standing crop. It signifies the efficacy and opulence of expansion.
- It is given as the number of organisms or their biomass per unit area.
- A terrestrial ecosystem with a high standing crop is characterized by a forest, whereas one with a low standing crop is characterized by grassland, followed by an arid ecosystem.
What is the Standing state?
- Standing state refers to the amount of nutrients, such as nitrogen, phosphorus, and calcium, present in the soil at any particular time.
- The following processes are responsible for the proper functioning of an ecosystem:
- Relationship between manufacturers and consumers
- Flow of energy through various trophic levels and nutrient cycling.