Energy Requirement of Different Organisms: Energy is described as the ability to perform work in the scientific world. Energy is required to carry out life processes inside every cell of all living things. Breaking down and building up molecules, as well as transporting numerous molecules across plasma membranes, all require energy. All of life’s activities necessitates the use of energy. A significant amount of energy is also lost to the environment as heat. Life is a story about energy flow – how it is captured, transformed, used for work, and then lost as heat. Because energy (unlike matter) cannot be regenerated, organisms require a steady supply of it.

Energy exists in many different forms. Examples of these are light energy, heat energy, mechanical energy, gravitational energy, electrical energy, sound energy, chemical energy, nuclear or atomic energy and so on. Chemical energy is what keeps life going. Where does this chemical energy come from in living organisms? Let’s dive deep through this article to learn more about the Energy Requirements of different organisms.

How Do Organisms Get Energy?

Food provides the chemical energy that organisms require. Food is made up of organic molecules with chemical bonds that store energy. There are two sorts of creatures that obtain food for energy: autotrophs and heterotrophs.

Autotrophs

Autotrophs are species that extract energy from nonliving sources and transfer it to the ecosystem’s living parts. They can also prepare their own food. In the process of photosynthesis, most autotrophs utilise the energy in the sunlight to create food. Photosynthesis is a process used by only a few organisms, including plants, algae, and bacteria. Producers are another name for autotrophs. They not only create food for themselves, but also for all other living creatures (known as consumers).

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Fig: (a) Plants, (b) Algae, and (c) Microorganism.

Heterotrophs

Heterotrophs are organisms that are unable to produce their own sustenance. They receive their nourishment instead by eating other species, which is why they are also known as consumers. They may eat autotrophs as well as other heterotrophs. All mammals and fungi, as well as many single-celled creatures, are heterotrophs. Except for the grass, all of the species in the diagram are consumers.

Food Chain

Let’s investigate how energy and nutrients circulate within an ecological ecosystem.

A food chain is a series of organisms that transmit nutrients and energy from one to the next when one eats another. Let’s take a look at the many components of a typical food chain, beginning at the bottom (the producers) and moving upward.

1. The primary producers are at the bottom of the food chain. Autotrophs are primary producers, which are usually photosynthetic organisms like plants, algae, or cyanobacteria.
2. Primary consumers are organisms that eat the primary producers. Herbivores, or plant-eaters, are the most common primary consumer. However, algae eaters and bacterium eaters are also common.
3. Secondary consumers are organisms that eat the primary consumers. Carnivores—meat-eaters—make up the majority of secondary consumers.
4. Tertiary consumers are organisms that eat the secondary consumers. These are carnivores that devour other carnivores, such as eagles or large fish.
5. There are additional layers in some food chains, such as quaternary consumers, which are carnivores that eat tertiary consumers. Apex consumers are organisms at the very top of a food chain.

Fig: Food Chain

Decomposers

1. Decomposers are bacteria that break down debris and dead creatures into smaller compounds. These bacteria acquire their energy, carbon, and nutrition from the organic substrates that they break down.
2. Decomposers are sometimes considered trophic levels in and of themselves. They eat decaying plant matter, the body of a half-eaten squirrel, or the remnants of a deceased eagle as a group; for example, they would contentedly consume decaying plant matter, the body of a half-eaten squirrel, or the remains of a slain eagle.
3. The decomposer level resembles the traditional consumer hierarchy of primary, secondary, and tertiary consumers in certain ways.
4. In many ecosystems, fungi and bacteria are the primary decomposers, using the chemical energy in dead matter and waste to power their metabolic processes.
5. Detritivores—detritus eaters or debris eaters—are another type of decomposer. Earthworms, crabs, slugs, and vultures are examples of multicellular organisms.

Fig: Decomposers

Chemotrophs

Chemotrophs are bacteria that eat other bacteria. Chemosynthetic bacteria, often known as chemotrophs, get their energy by decomposing chemical molecules in their surroundings. Nitrogen-containing ammonia is an example of a chemical that bacteria break down. These bacteria are crucial because they aid in the cycling of nitrogen through the environment for utilisation by other living things. Because living creatures cannot produce nitrogen, it must be recycled on a regular basis. Nitrogen is required by organisms in order to produce organic substances such as DNA.

Mutualism

Some bacteria rely on the presence of other organisms to survive. Some bacteria, for example, dwell in the roots of legumes like pea plants. Bacteria convert nitrogen-containing compounds into nitrogen that can be used by plants. In the meantime, the bacteria are fed by the root. Both the bacteria and the plant profit from this interaction, which is known as mutualism.Gut bacteria are another type of mutualistic bacteria. These are microorganisms that live in animals’ intestines. They’re usually beneficial microorganisms that the host organism requires. These microorganisms don’t kill their hosts because that would also kill the bacteria.

Fig: The nodules on a soybean root that contain mutualistic bacteria help to deliver nitrogen to the plant.

Parasitism

Other bacteria are parasitic, which means they can make you sick. The bacteria benefit from parasitism, while the other organism suffers.

Trophic Levels

Trophic levels refer to the feeding positions in a food chain or web. In the table below, the various trophic levels are defined. The table also includes examples. At least two or three trophic levels exist in all feeding chains and webs. In most cases, there are no more than four trophic levels.

Trophic Level	Where It Gets Food	Example
1st Trophic Level: Producer	Makes its own food	Plants make food
2nd Trophic Level: Primary Consumer	Consumes producers	Mice eat plant seeds
3rd Trophic Level: Secondary Consumer	Consumes primary consumers	Snakes eat mice
4th Trophic Level: Tertiary Consumer	Consumes secondary consumers	Hawks eat snakes

Many consumers take food from multiple trophic levels. When it comes to plants like veggies, humans are the primary consumers. When they eat cows, they are secondary consumers. When they eat salmon, they are secondary consumers.

Trophic Levels and Energy

From lower to higher trophic levels, energy is transmitted up a food chain or web. However, only around 10% of the energy accessible at one level is available in the next. The ecological pyramid is a good example of this. What happens to the remaining 90% of energy? It is utilised in metabolic activities or released as heat into the environment. This energy loss explains why a food chain or web rarely has more than four trophic levels. There may be a fifth trophic level, but there is usually insufficient energy to maintain any higher levels.

Fig: Energy Pyramid

Energy Molecules: Glucose and ATP

Glucose and ATP are the two most common chemical energy molecules used by organisms. Both molecules are used as fuel by all living things. Both chemicals are important in the photosynthesis process.

Glucose

Glucose has the chemical formula C6H12O6 and is a simple carbohydrate. Chemical energy is stored in a concentrated, stable form. Glucose is a type of energy delivered in your bloodstream and absorbed by each of your trillions of cells. The end product of photosynthesis is glucose, which is practically universal nourishment for life.

ATP

The energy-carrying molecule ATP (adenosine triphosphate) is used by cells to generate energy. All cells use it for energy in most biological functions. The first half of photosynthesis produces ATP, which is subsequently used for energy during the second half of photosynthesis when glucose is produced. As indicated in the diagram below, ATP releases energy by giving up one of its three phosphate groups (Pi) and converting it to ADP (adenosine diphosphate, which has two phosphate groups). As a result, ATP decomposition into ADP + Pi is a catabolic reaction that releases energy (exothermic). ADP and Pi are combined to form ATP, which is an anabolic reaction that consumes energy (endothermic).

Why Do Organisms Need Both Glucose and ATP?

Why do living things require glucose when ATP is the energy molecule used by cells? Why don’t autotrophs just produce ATP and call it a day? The solution can be found in the “packing.” A glucose molecule has more chemical energy in a smaller “package” than an ATP molecule. Glucose also has higher stability than ATP. As a result, glucose is more efficient at storing and transporting energy. Glucose, on the other hand, is far too potent for cells to utilise. ATP, on the other hand, has just the proper quantity of energy to power cell life functions. Living beings require both glucose and ATP for these reasons.

How Does Energy Flow Through Living Things?

1. Photosynthesis is the first step in the transmission of energy through living organisms.
2. The energy from the sun is stored in the chemical bonds of glucose in this process.
3. Cells release stored energy and produce the ATP they require by breaking the chemical bonds in glucose.
4. Cellular respiration is the mechanism through which glucose is broken down and, ATP is produced.
5. The processes of photosynthesis and cellular respiration are similar to the two sides of the same coin. This can be seen in the diagram below.
6. The reactants of one process are the products of another. In living organisms, the two processes work together to store and release energy. In addition, the two processes collaborate to recycle oxygen in the Earth’s atmosphere.

Fig: Photosynthesis and cellular respiration

Summary

The ability to work is defined as energy. All living creatures and every live cell require it to carry out life functions such as breaking down and reassembling molecules, as well as moving numerous molecules across cell membranes. Chemical energy is the type of energy that living beings require for these operations, and it originates from food. Food is made up of organic molecules with chemical bonds that store energy. Autotrophs are organisms that produce their own sustenance.

Photosynthesis, for example, is how plants produce food. Producers are another name for autotrophs. Heterotrophs devour other creatures to get food. Consumers are also known as heterotrophs. Glucose and ATP are the most common energy molecules used by organisms. Glucose is a compact, stable form of energy that travels through the bloodstream and is absorbed by cells. ATP is a less energetic form of energy that is used to power cellular functions. Photosynthesis, which produces glucose, is the first step in the transmission of energy through living things. Cellular respiration is the mechanism by which organisms’ cells break down glucose and produce the ATP they require.

FAQs on Energy Requirement of Different Organisms

Q.1. What is the role of energy in living organisms?
Ans: To grow and reproduce, maintain their structures, and respond to their environments, all living organisms require energy; metabolism is the set of mechanisms that makes energy available for cellular operations.

Q.2. What is the most significant component of a food chain?
Ans: Decomposers are organisms that decompose dead plants and animals. Other organisms’ waste is also broken down by them.

Q.3. How many types of trophic levels are there?
Ans: At least two or three trophic levels exist in all feeding chains and webs. In most cases, there are no more than four trophic levels. Many consumers take food from multiple trophic levels.

Q.4. Why are decomposers an important component of a food chain?
Ans: Decomposers play an essential role in the food chain because they ensure that primary producers have a steady supply of nutrients.

Q.5. Why do organisms need both Glucose and ATP?
Ans: Glucose also has higher stability than ATP. As a result, glucose is more efficient at storing and transporting energy. Glucose is far too potent for cells to utilise. ATP, on the other hand, has just the proper quantity of energy to power cell life functions.

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