Energy Flow in Ecosystem

Energy Flow in Ecosystem : Introduction

Life on Earth depends significantly on the movement of energy within ecosystems. Ecosystems on Earth receive almost all of their energy from the Sun. Once on Earth, this solar energy is divided throughout ecosystems in a very intricate way. A food chain or food web analysis is a straightforward technique to examine this distribution.

Food chains and food webs are graphic representations of how energy flows through ecosystems. Ecologists use these diagrams to answer questions about the structure, function, and biodiversity of an ecosystem. Questions might include: which animals eat which other animals in a particular ecosystem? Are there any organisms that don't have predators? What are the relationships between predator and prey species? How do energy, nutrients, gases, and water circulate within the system? How many links are in a food chain or food web in an ecosystem? Food chains start with plant producers (like grasses, trees, and algae) that use solar energy to convert carbon dioxide (CO) from the atmosphere into organic compounds through photosynthesis. According to the US DOE, "Biological activities depend on energy transfer across the Earth's system."

Energy Flow in Ecosystem: Food Chain.

A food chain is a network of links in a food web that runs in a straight line from producer organisms to an apex predator, detritivore, or decomposer species. A food chain also demonstrates how organisms are connected to one another through the foods they consume. A food chain's various levels each correspond to a different trophic level. 

 Types of Food Chain

• The grazing food chain: It is made up of animals that eat both plants and other animals. Green plants are always at the top of the food chain.
• The detritus food chain: It begins with dead organic matter (detritus), passes through decomposers (bacteria, fungi), and then moves on to detritus feeders (earthworms), which are then consumed by carnivores.
• The parasitic food chain (PFC): It is a type of food chain in which large organisms are used as either the producer or the consumer, resulting in the food being transferred to the smaller organism.

Levels in the Food Chain:

A food chain, or trophic level, has different levels that all start at the producers who initially absorb the sun's light. It then moves up to the organisms that eat it or decompose it, and so on, all the way to the apex predators who can only decompose it later.

A specific amount of biomass is present on each level and is carried over to the following level. However, because of the above-mentioned second law of thermodynamics, this transfer is not very efficient. Ecological efficiency is the concept that only a portion of what is consumed is actually converted into usable biomass from level to level, with typical efficiencies of 2–40%. 

More energy is lost as it ascends the food chain, the more levels there are. Assuming a 10% efficiency, if the sun provided 10,000 units of energy initially, and there were four levels between it and the apex predator, each level would receive 10,000 times less energy until the apex predator only received 1 unit.

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Energy Flow of Ecosystem: Productivity

The quantity of organic matter accumulated over a given period of time determines an ecosystem's productivity. There are two different kinds of it: primary productivity and secondary productivity.

Primary productivity

• The rate of biomass or organic matter production by plants over time and per unit of area during photosynthesis.
• Net primary productivity (NPP) and gross primary productivity (GPP) are two ways to categorize it.
• The rate at which organic matter is produced during photosynthesis is known as an ecosystem's gross primary productivity.
• Plants use a specific amount of GPP during respiration. Net primary productivity (P) is the sum of gross primary productivity and respiration losses (R) (NPP).

Secondary Productivity

• The rate at which consumers generate new organic matter is referred to as "secondary productivity." The biomass that is available for consumption by heterotrophs is known as net primary productivity (herbivores and decomposers).
• The highest rates of productivity are found where land and water meet. Examples include coral reefs, estuaries, and alluvial plains. On the other hand, production is extremely low in deserts and deep oceans.

Ecosystem Energy Flow: Food Web 

A food web is a visual representation of what eats what in an ecological community and the way in which food chains naturally connect to one another. The food web is also referred to as a consumer-resource system. All life forms can be broadly categorized by ecologists into one of two trophic levels: 1) the autotrophs, and 2) the heterotrophs. Autotrophs convert inorganic materials, such as minerals and gases like carbon dioxide, into organic matter in order to sustain their bodies, grow, develop, and reproduce. Energy is needed for these chemical reactions, and the majority of it is provided by the Sun and photosynthesis. A very small amount is also provided by bioelectrogenesis in wetlands and mineral electron donors in hydrothermal vents and hot springs. These trophic levels aren't binary; instead, they're a gradient that includes complete autotrophs, which get all of their carbon from the atmosphere; mixotrophs (like carnivorous plants), which are autotrophs that get some of their organic material from places other than the atmosphere and complete heterotrophs, which have to consume other organisms to get organic material.

Energy Flow in Ecosystem: Trophic Level

The relationships get more complicated the more closely the food webs are examined. The system must be conceptualized because diagrams showing species connections become tangled and confusing. The trophic level is the fundamental abstraction of the food chain or food web. Each time energy is transferred between organisms, a higher trophic level is said to have received the energy.

At pyramids, each of the sequential, hierarchical levels in a food chain known as a trophic level, is made up of organisms that have a similar role in the food chain and a similar nutritional relationship to the primary energy sources:

• Primary producer (green plants) trophic level
• Primary consumer (herbivores) trophic level
• Secondary consumer (predators) trophic level
• Tertiary consumer (apex predator) trophic level

Energy Flow in an Ecosystem: Energy flows between trophic levels.

When organic molecules from one organism's body are consumed by another, energy can go from one trophic level to the next. But typically, the movement of energy between trophic levels is not very efficient. At each level, from producers to consumers, only a small percentage of the primary producers' energy will be passed on to the next higher trophic level.

In marine and freshwater ecosystems, for example, about 10% of the producer's production will eventually end up as biomass at the consumer level. The amount of energy that is lost from one trophic level to another depends on how efficient each organism is at getting or making food.

One way to increase the efficiency of food transport would be to have organisms that can store food, waiting for a better time to eat.

Energy Flow in an Ecosystem: Ecological Pyramids

An ecological pyramid shows the relationships between various living things at various trophic levels graphically.

It is apparent that these pyramids are shaped like real pyramids, with the lowest trophic level—the producers—covering the base, which is the largest. The subsequent trophic level, i.e., the principal consumers and so on, resides on the next level.

There will be a significant amount of errors produced by a sample space with only a few species or numbers. Because of this, all the  calculations for the construction of these ecological pyramids must take into account all the creatures at a certain trophic level.There are three types of pyramids:

Pyramid of Numbers

Pyramid of Numbers display the number of distinct creatures in each trophic level. Depending on the habitat, they may be upright, inverted, or lumpy in certain ways.

The pyramid of numbers can be upright or upside-down. At the base of the upright pyramid, there are the most producers, and as you go up the pyramid, there are fewer and fewer creatures. The parasite food chain's number pyramid is constantly changing in any biological system. The amount of living things in each supplement level starts at the bottom and moves up the inverted pyramid in small, incremental steps. According to the ecological pyramid, the number of nutrients or previous supplements determines the number of living things in a trophic level. Herbivore populations in inland habitats do not quite match those of grass plants.Because carnivores eat herbivores, there are fewer carnivores than there are herbivores. Likewise, the least amount of carnivores are found at the most severe level of ward on carnivores.

Pyramid of Energy

The Pyramid of Energy shows how energy moves up and down trophic levels. The pyramid below, for instance, displays the gross productivity at each trophic level for the Silver Springs environment. An energy pyramid typically displays rates of energy transfer across trophic levels rather than precise energy storage levels. It may have energy units like text kcal/m2, text kcal/yr, etc.

The energy pyramid is often upright. The entire energy content of each trophic level in an ecological system is covered by this pyramid. The maximum amount of solar energy was captured at the base of this pyramid. But as Lindeman's 10% regulation law shows, the amount of energy at a greater level gradually decreases. Natural food contains energy, some of which is lost as heat energy in breath, part of which is used in physiological cycles, and the remainder is used by decomposers. As energy moves from one trophic level to the next in the pyramid of energy, some energy is lost in the process. During energy travel, each level of this pyramid loses 60 to 90% of its energy.

Pyramid of Biomass

The term "pyramid of biomass" refers to the ecological pyramid that is constructed by ordering the amount of dry weight of diverse animals in accordance with the trophic level in an ecological system. The dry weight of different living things is arranged in layers depending on the trophic level of an environment, with 15–20% of biomass from one layer moving on to the next.This pyramid can be upright or inverted, just like a pyramid of numbers.

 Ecological systems in forests and grasslands are examples of standing biomass pyramids. The lake's ecosystem serves as an example of an inverted biomass pyramid. In the food chain, biomass pyramids are tremendously important. This biomass pyramid represents the magnitude of all living things put together. The biomass is a pyramid that represents the total mass of each food layer in a particular food chain in an ecosystem.The biomass gradually decreases from the lower trophic level to the higher trophic level in this food chain. The biomass of the producer is at the top of this ecological pyramid, while the biomass of the tertiary consumer is at the bottom. The biomass of primary producers is highest and that of secondary consumers is lowest in the forest ecosystem. The aquatic ecosystem may have a reversed biomass pyramid.