This type of food chain goes from dead organic matter into microorganisms and then to organisms feeding on detritus (detrivores) and their predators. Such ecosystems are thus less dependent on direct solar energy. These depend chiefly on the influx of organic matter produced in another system. For example, such type of food chain operates in the decomposing accumulated litter in a temperate forest.
Main Difference
Food is the basic source of energy for all organisms in the ecosystem. The flow of food is from one organism to another. So, a series or chain of organisms in which each of them depends on one and other as a source of food or energy is called a food chain. The food chain can further be divided into two main types; Grazing Food Chain and Detritus Food Chain. The main difference between both these types of the food chain is that grazing food chain starts from the green plants, which are the primary producers, whereas detritus food chain begins from the dead organic matter or decomposed material, which is usually present in the soil. The energy for the grazing food chain comes from the sun as the autotrophs (green plants) prepare their food (photosynthesis) amid the presence of the sunlight. On the other hand, the energy for the detritus food chain is taken from the detritus or the decomposed materials.
Comparison Chart
What is Grazing Food Chain?
The grazing food chain is one of the major types of food chain that is seen as a food chain process dominantly occurring in organisms. The grazing food chain starts from the autotrophs (green plants), the major energy for this chain is taken from the sun as the plants carry out the process of photosynthesis in the presence of sunlight. The green plants work as the primary producer of this type of food chain; later the herbivores get fed upon the green plants. The chain goes on further as the primary consumers (herbivores) are eaten by the secondary consumers (omnivores) in this type of food chain. This food chain doesn’t consist of microbes or other decomposers; it is carried out by the macroscopic organisms. The grazing food chain is the simpler type of food chain as it begins from the primary producers (green plants), who are the dominant producers in different ecosystems across the globe. The name of the food chain itself tells that it possess the green plants as a major source or the one starting off the chain.
What is Detritus Food Chain?
The detritus food chain is the type of food chain that ensures maximum utilization and minimum wastage of the available material. This food chain starts from the dead organic matter or other such wastes; further, this material is eaten by the animal, and later this animal gets eaten by another animal in the soil. The chain keeps on going until the organic matter is composed. This type of food chain is quite handy in fixation of inorganic nutrients and utilizing up to the maximum. Detritus food chain has the remains of detritus as the major source of energy, and this process gets completed by the subsoil organisms, which can either be macroscopic or microscopic. Unlike the grazing food chain, the detritus food chain produces a large amount of energy to the atmosphere.
- The grazing food chain starts from the autotrophs (green plants), whereas the detritus food chain begins from the detritivores.
- In grazing food chain the energy is taken from the sunlight as green plants prepare food in the presence of it while in the detritus food chain the main energy source is remain of detritus.
- In grazing food chain macroscopic organisms are involved, on the other hand, in the detritus food chain, subsoil organisms are involved, which can either be macroscopic or microscopic.
- Unlike the grazing food chain, the detritus food chain produces a large amount of energy to the atmosphere.
The detritus food chain differs from the grazing food chain in several significant ways. First, the organisms making it up are in general smaller in size. Second, the functional roles of the different organisms do not fall as neatly into categories like the grazing food chain's trophic levels. Finally, detritivores live in environments (soil, sea bed, etc.) that are rich in scattered food particles. As a result, decomposers are less mobile than herbivores or carnivores.
The organisms of the detritus food chain include members of many different species of animals and plants, such as algae, bacteria, slime molds, fungi, protozoa, insects, mites, crustaceans, centipedes, mollusks, worms, sea cucumbers, and even some vertebrates (Figure 9n-1). These organisms consume organic wastes, shed tissues, and the dead bodies of both plants and animals.
| Figure 9n-1: Earthworms are one of the most important soil decomposers. These organisms consume vast amounts of organic matter and mineral soil. As the organic matter passes through their digestive system, it is subjected to digestive enzymes and the grinding action of mineral soil particles. The amount of material consumed per day is often equal to their body weight. |
Decomposers tend to always be active, processing large amounts of organic matter and releasing a great deal of energy mostly as heat from metabolic activities (e.g., compost heap). The end result of decomposition is the conversion of organic matter back into its original inorganicnutrient form. In mature forest and grassland soils, the decomposition process establishs an equilibrium over time where litterfall additions equal the amount of organic matter decomposed.
The rate of decomposition in a detritus food chain is controlled by many factors. In most terrestrial ecosystems, temperature and soil oxygen and moisture content tend to be the primary variables controlling the activities of decomposers. In some ecosystems, oxygen may not be readily available. In these cases aerobic respiration cannot take place, and the breakdown of organic compounds and energy extraction must then proceed by anaerobic means like fermentation. Organisms involved in fermentation include bacteria and yeast. Anaerobic decomposition releases much less energy from organic matter than does aerobic respiration. The end products of anaerobic decomposition include molecules such as carbon dioxide, water, and humus. They also include small-molecule alcohols, organic acids, ptomaines, amines, and other products, as well as gaseous substances such as methane.
Because respiration is so much more efficient at releasing the energy contained in organic molecules, the activity of the detritus food chain is much higher in an aerobic environment, and the breakdown of materials more complete. Organic matter breakdown is substantially slower and less complete in anaerobic environments. It also results in the accumulation of undegraded organic matter in the form of peat, organic soils, and highly organic sediments.
In conclusion, there is no waste in a properly functioning natural ecosystem. Everything once living or alive will be consumed by decomposers at some time and returned to inorganic form.
Detritus food chain starts from dead organic matter and goes to detritus feeding organisms and on their predators.Detritus food chain are found in a variety of situations such as the
bottom of Lakes and oceans which are too dark to carry out photosynthesis.
examples of decomposer food chain are: (1) leaves and dead plants → soil mites → insects. (2) organic matter → Protozoa → rotifers
This type of food chain goes from dead organic matter into microorganisms and then to organisms feeding on detritus (detrivores) and their predators. Such ecosystems are thus less dependent on direct solar energy. These depend chiefly on the influx of organic matter produced in another system. For example, such type of food chain operates in the decomposing accumulated litter in a temperate forest.
• Source of energy is detritus not sun.
• Source of energy is detritus not sun.
• Composed of a long chain of detritus eating organisms (detritivores)
• In some ecosystems (e .g. Tropical rain forest) more energy flows in this chain than grazing food chain.
• In some ecosystems (e .g. Tropical rain forest) more energy flows in this chain than grazing food chain.
This type of food chain goes from dead organic matter into microorganisms and then to organisms feeding on detritus (detrivores) and their predators. Such ecosystems are thus less dependent on direct solar energy. These depend chiefly on the influx of organic matter produced in another system. For example, such type of food chain operates in the decomposing accumulated litter in a temperate forest.
Significance of food chain:
1. The studies of food chain help understand the feeding relationship and the interaction between organisms in any ecosystem.
2. They also help us to appreciate the energy flow mechanism and matter circulation in ecosystem and understand the movement of toxic substances in the ecosystem.
3. The study of food chain helps us to understand the problems of bio-magnifications.
Detritus food chain begins with the dead organic matter. It is made up of decomposers (saprotrophs) which are heterotrophic organisms. For example, fungi and bacteria. They meet their energy and nutrient requirements by degrading dead organic matter or detritus.
In detritus food chain, energy comes from organic matter (or detritus) generated in trophic levels of the grazing food chain. It begins with detritus such as dead bodies of animals or fallen leaves, which are then eaten by decomposers or detritivores. These detritivores are in turn consumed by their predators. It is usually smaller as compared to the grazing food chain. Primary consumers are 'detritivores' including protozoans, bacteria, fungi, etc which feed upon the detritus saprophytically.
So the correct option is 'dead organic matter'
What is Food Chain?
The series of organisms of an ecosystem through which the food and energy present in it and passes with
each member is called food chain. A food chain consists of producers (green plants), consumers (animals
and man) and decomposers (micro organisms). Basically there are two types of food chains: grazing food
chain and detritus food chain.
Grazing food chain starts with green plants which are the producers. The green plants or producers are
grazed by herbivorous animals which are further eaten by carnivores.
Primary producers (Autotrophs)-> Primary consumers (Herbivores)-> Secondary Consumers (Carnivores)
Grass->Rabbit->Fox->Lion
1. The chain begins with green plants (producers) at the first trophic level
2. Energy for this food chain comes from the sun
3. Food chain adds energy into the ecosystem
4. The food chain fixes inorganic nutrients
5. It consists of all macroscopic organisms
Detritus food chain starts with dead organic matter which is eaten by animals which in turn are eaten by
other animals in the soil. a large amount of energy flows through the detritus food chain. ultimately the
organic matter is decomposed.
Detritus like leaf litter decomposed by microbes (bacteria) in soil (detritivore)->Earthworm (detrivore)->Rat-
>Snake->Eagle
1. The chain begins with detritivores (decomposers) at the first trophic level
2. Energy for this food chain comes from remains of detritus
3. This food chain take up energy from the detritus, ensuring maximum utilization and minimum wastage
4. The food chain helps in fixing inorganic nutrients
5. It consists of sub soil organisms.