essay about food chain and food web

• Food Chain and Food Web

Food chain is a linear sequence of organisms which starts from producer organisms and ends with decomposer species . Food web is a connection of multiple food chains. Food chain follows a single path whereas food web follows multiple paths. From the food chain, we get to know how organisms are connected with each other. Food chain and food web form an integral part of this ecosystem. Let us take a look at the food chain and a food web and the difference between them.

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In scientific terms, a food chain is a chronological pathway or an order that shows the flow of energy from one organism to the other. In a community which has producers, consumers , and decomposers, the energy flows in a specific pathway. Energy is not created or destroyed. But it flows from one level to the other, through different organisms.

A food chain shows a single pathway from the producers to the consumers and how the energy flows in this pathway. In the animal kingdom , food travels around different levels. To understand a food chain better, let us take a look at the terrestrial ecosystem.

Food chain in a Terrestrial Ecosystem

The sun is the source of energy, which is the initial energy source. This is used by the producers or plants to create their own food, through photosynthesis and grow. Next in this chain is another organism, which is the consumer that eats this food, taking up that energy.

The primary consumers are the organisms that consume the primary producers.  In a terrestrial ecosystem, it could be a herbivore like a cow or a goat or it could even be a man.  When a goat is consumed by man, he becomes the secondary consumer.

Learn more about Biogeochemical Cycle here in detail.

As the energy goes one level up, the food chain also moves up. Each level in the food chain is called a trophic level. The different trophic levels are Primary producers, primary consumers, secondary consumers, tertiary consumers and quaternary consumers.

Example of food chain

Grass (Producer) —–Goat (Primary Consumer) —– Man (Secondary consumer)

When dead organic matter becomes the starting of a food chain, then it is called the detritus food chain (DFC). The decomposers, which are the fungi and bacteria , feed on the organic matter to meet the energy requirements. The digestive enzymes secreted by the decomposers help in the breakdown of the organic matter into inorganic materials.

Download Ecosystem Cheat Sheet PDF

Browse more topics under ecosystem.

• Components of Ecosystem
• Ecological Pyramid and Ecological Succession
• Biogeochemical Cycle

Many interconnected food chains make up a food web. When you look at the larger picture, a food web shows a realistic representation of the energy flow through different organisms in an ecosystem.

Learn more about Components of Ecosystem here in detail.

Sometimes, a single organism gets eaten by many predators or it eats many other organisms. This is when a food chain doesn’t represent the energy flow in a proper manner because there are many trophic levels that interconnect. This is where a food web comes into place. It shows the interactions between different organisms in an ecosystem.

The following diagram shows the energy flow between various organisms through a food web.

Solved Questions For You

Q: Name the common detritivores in an ecosystem. Do they play a significant role? Support your answer.

Ans:   Earthworms, dung beetles, and sea cucumbers are some of the common detritivores in an ecosystem. They play a crucial role in the ecosystem, by decomposing the dead organic matter.

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What Is a Food Web? Definition, Types, and Examples

• Emory University
• Chattahoochee Technical College

Treehugger / Ellen Lindner

• Animal Rights
• Endangered Species

Food Web Definition

Trophic levels in a food web, energy movement, food web vs. food chain, types of food webs, importance of the study of food webs.

A food web is a detailed interconnecting diagram that shows the overall food relationships between organisms in a particular environment. The simplest explanation is that food webs are "who eats whom" diagrams showing the complex feeding relationships for a specific ecosystem.

The study of food webs is important, as such webs can show how energy flows through an ecosystem . It also helps us understand how toxins and pollutants become concentrated within a particular ecosystem. Examples include mercury bioaccumulation in the Florida Everglades and mercury accumulation in the San Francisco Bay.

Food webs can also help us study and explain how species diversity is related to how they fit within the overall food dynamic. They may also reveal critical information about the relationships between invasive species and those native to a particular ecosystem.

Key Takeaways: What Is a Food Web?

• Think of a food web as a "who eats whom" diagram showing an ecosystem's complex feeding relationships.
• Knowing the interconnectedness of organisms in energy transfer within an ecosystem is vital to understanding food webs and how they apply to real-world science.
• An increase in toxic substances, like man-made persistent organic pollutants (POPs), can profoundly impact ecosystem species.
• By analyzing food webs, scientists can study and predict how substances move through the ecosystem to help prevent the bioaccumulation and biomagnification of harmful substances.

The concept of a food web, previously known as a food cycle, is typically credited to Charles Elton, who first introduced it in his book Animal Ecology, published in 1927. He is considered one of the founders of modern ecology and his book is a seminal work. In this book, he also introduced other important ecological concepts like niche and succession .

In a food web, organisms are arranged according to their trophic level. An organism's trophic level refers to how it fits within the food web and is based on how it feeds. 

There are two main designations: autotrophs and heterotrophs. Autotrophs make their food, while heterotrophs do not. Within this broad designation are five main trophic levels: primary producers, primary consumers, secondary consumers, tertiary consumers, and apex predators.

A food web shows how the different trophic levels within various food chains interconnect and how energy flows through them within an ecosystem.

Primary Producers

Primary producers make their food via photosynthesis, which uses the sun's energy to make food by converting its light energy into chemical energy. Examples of primary producers include plants and algae. These organisms are also known as autotrophs.

Primary Consumers

Primary consumers are animals that eat the primary producers. They are named as such because they are the first organisms to eat the primary producers who make their own food. Primary consumers are also known as herbivores. Examples of animals in this designation are rabbits, beavers, elephants , and moose.

Secondary Consumers

Secondary consumers consist of organisms that eat primary consumers. Since secondary consumers are animals that eat the animals that eat the plants, they are called carnivorous or omnivorous. Carnivores eat animals, while omnivores consume both other animals and plants. Bears are an example of a secondary consumer.

Tertiary Consumers

Similar to secondary consumers, tertiary consumers can be carnivorous or omnivorous. The difference is that secondary consumers eat other carnivores. An example is an eagle.

Apex Predators

Lastly, the final level is composed of apex predators . Apex predators are at the top because they do not have natural predators. Lions are an example.

Decomposers and Detritivores

Additionally, organisms known as decomposers consume dead plants and animals and break them down. Fungi are examples of decomposers. Other organisms known as detritivores consume dead organic material. A vulture is an example of a detrivore.

Energy flows through the different trophic levels. It begins with the sun's energy, which autotrophs use to produce food. This energy is transferred up the levels as the different organisms are consumed by members of the levels above them.

Approximately 10% of the energy transferred from one trophic level to the next is converted to biomass—the overall mass of an organism or the mass of all the organisms that exist in a given trophic level.

Since organisms expend energy to move around and go about their daily activities, only a part of the energy consumed is stored as biomass.

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While a food web contains all constituent food chains in an ecosystem, food chains are a different construct. A food web can be composed of multiple food chains, some very short and others much longer. Food chains follow the flow of energy as it moves through the chain. The starting point is the energy from the sun, and this energy is traced as it moves through the food chain. This movement is typically linear, from one organism to another.

For example, a short food chain may consist of plants that use the sun's energy to produce their food through photosynthesis and the herbivore that consumes these plants. This herbivore may be eaten by two different carnivores, which are a part of this food chain. When these carnivores are killed or die, the decomposers in the chain break down the carnivores, returning nutrients to the soil that can be used by plants.

This brief chain is one of many parts of the overall food web that exists in an ecosystem. Other food chains in the food web for this particular ecosystem may be very similar to this example or may be much different. 

Since it is composed of all of the food chains in an ecosystem, the food web shows how the organisms in an ecosystem interconnect.

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There are several types of food webs, which differ in how they are constructed and what they show or emphasize about the organisms within the particular ecosystem depicted.

Scientists can use connectance and interaction food webs, along with energy flow, fossil, and functional food webs, to depict different aspects of the relationships within an ecosystem. They can also further classify the types of food webs based on the ecosystem being depicted in the web.

Connectance Food Webs

In a connectance food web, scientists use arrows to show one species being consumed by another. All of the arrows are equally weighted. The degree of strength of the consumption of one species by another is not depicted.

Interaction Food Webs

Like in connectance food webs, scientists also use arrows in interaction food webs to show one species being consumed by another. However, the arrows used are weighted to show the degree or strength of consumption of one species by another.

The arrows depicted in such arrangements can be wider, bolder, or darker to denote the strength of consumption if one species typically consumes another. If the interaction between species is weak, the arrow can be very narrow or nonexistent.

Energy Flow Food Webs

Energy flow food webs depict the relationships between organisms in an ecosystem by quantifying and showing the energy flux between organisms.

Fossil Food Webs

Food webs can be dynamic, and the food relationships within an ecosystem can change over time. Scientists attempt to reconstruct the relationships between species in a fossil food web based on available evidence from the fossil record.

Functional Food Webs

Functional food webs depict the relationships between organisms in an ecosystem by depicting how different populations influence the growth rate of other populations within the environment.

Food Webs and Type of Ecosystems

Scientists can also subdivide the above types of food webs based on the type of ecosystem. For example, an energy-flow aquatic food web would depict the energy flux relationships in an aquatic environment. In contrast, an energy-flow terrestrial food web would show such relationships on land.

Food webs show us how energy moves through an ecosystem, from the sun to producers to consumers. The interconnectedness of how organisms are involved in this energy transfer within an ecosystem is vital to understanding food webs and how they apply to real-world science.

Just as energy can move through an ecosystem, other substances can also move through. There can be devastating effects when toxic substances or poisons are introduced into an ecosystem.

Bioaccumulation and biomagnification are important concepts. Bioaccumulation is the accumulation of a substance, like poison or a contaminant, in an animal. Biomagnification refers to the buildup and increase in the concentration of said substance as it is passed from trophic level to trophic level in a food web.

This increase in toxic substances can profoundly impact species within an ecosystem. For example, man-made synthetic chemicals often do not break down easily or quickly and can build up in an animal's fatty tissues over time. These substances are known as persistent organic pollutants (POPs).

Marine environments are common examples of how these toxic substances can move, such as from phytoplankton to zooplankton, then to fish that eat the zooplankton, then to other fish (like salmon) who eat those fish, and up to orca who eat salmon. Orcas have a high blubber content so the POPs can be found at very high levels. These levels can cause several issues like reproductive problems, developmental issues with their young as well as immune system issues.

By analyzing and understanding food webs, scientists can study and predict how substances may move through the ecosystem. They can then better help prevent the bioaccumulation and biomagnification of these toxic substances in the environment through intervention.

• “ Food Webs and Networks: the Architecture of Biodiversity .” Life Sciences at the University of Illinois at Urbana-Champaign , Biology Department.
• “ 11.4: Food Chains and Food Webs .” Geosciences LibreTexts , Libretexts.
• “ Terrestrial Food Webs .” Smithsonian Environmental Research Center.
• “ Bioaccumulation and Biomagnification: Increasingly Concentrated Problems! ” CIMI School.
• Food Chains and Food Webs: Learn the Difference
• Energy Flow in Ecosystems
• What Are Biotic and Abiotic Factors in an Ecosystem?
• Why Choosing Nectar-Rich Plants for a Garden Is So Important
• How Does Mercury Get in Fish?
• What Is an Indicator Species? 10 Key Examples
• Why Flowering Meadows Are Better Than Lawns
• What Is a Trophic Cascade? Definition and Ecological Impact
• What Is a Pioneer Species?
• Lichens in a Garden and What They Tell You
• Understanding the Sustainable Seafood Industry
• Types of Forests: Definitions, Examples, and Importance
• What Is Glitter? Environmental Impact and Sustainable Alternatives
• 10 Stunning Plants and Sea Creatures on the Ocean Floor
• Male Spiders Fight Less When There Are More Females Around
• 3 Types of Biodiversity: Overview and Importance

ENCYCLOPEDIC ENTRY

A food web consists of all the food chains in a single ecosystem.

Biology, Ecology

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A  food web   consists of all the  food chains in a single  ecosystem . Each living thing in an ecosystem is part of  multiple   food chains . Each food chain is one possible path that  energy  and  nutrients may take as they move through the ecosystem . All of the interconnected and overlapping food chains in an ecosystem make up a food web . Trophic Levels Organisms in food webs are grouped into categories called  trophic levels . Roughly speaking, these levels are divided into  producers (first trophic level ),  consumers , and  decomposers (last trophic level ). Producers Producers make up the first trophic level . Producers , also known as  autotrophs , make their own food and do not depend on any other organism for nutrition. Most autotrophs use a process called  photosynthesis  to create food (a nutrient called  glucose ) from sunlight ,  carbon dioxide , and water. Plants are the most familiar type of autotroph , but there are many other kinds.  Algae , whose larger forms are known as  seaweed , are autotrophic .  Phytoplankton , tiny organisms that live in the ocean, are also autotrophs . Some types of  bacteria  are autotrophs . For example, bacteria living in active  volcanoes use  sulfur , not carbon dioxide , to produce their own food. This process is called  chemosynthesis . Consumers The next trophic levels are made up of animals that eat producers . These organisms are called consumers . Consumers can be  carnivores (animals that eat other animals) or  omnivores (animals that eat both plants and animals). Omnivores , like people, consume many types of foods. People eat plants , such as  vegetables and fruits . We also eat animals and animal products, such as meat, milk, and eggs. We eat  fungi , such as mushrooms. We also eat algae , in  edible   seaweeds like  nori (used to wrap  sushi  rolls) and  sea lettuce  (used in salads). Bears are omnivores , too. They eat berries and mushrooms, as well as animals such as salmon and deer. Primary consumers are  herbivores . Herbivores eat plants , algae , and other producers . They are at the second trophic level . In a  grassland   ecosystem , deer, mice, and even elephants are herbivores . They eat grasses,  shrubs , and trees. In a  desert   ecosystem , a mouse that eats  seeds and  fruits is a primary consumer . In an ocean ecosystem , many types of fish and turtles are herbivores that eat algae and  seagrass . In  kelp forests , seaweeds known as giant kelp provide shelter and food for an entire ecosystem .  Sea urchins are powerful primary consumers in kelp forests . These small herbivores eat dozens of kilograms (pounds) of giant kelp every day. Secondary consumers eat herbivores . They are at the third trophic level . In a desert ecosystem , a secondary consumer may be a snake that eats a mouse. In the kelp forest , sea otters are secondary consumers that hunt sea urchins . Tertiary consumers eat the secondary consumers . They are at the fourth trophic level . In the desert ecosystem , an owl or eagle may prey on a snake. There may be more levels of consumers before a chain finally reaches its  top predator . Top predators , also called  apex predators , eat other consumers . They may be at the fourth or fifth trophic level . They have no natural enemies except humans. Lions are apex predators in the grassland ecosystem . In the ocean, fish like the great white shark are apex predators . In the desert , bobcats and mountain lions are top predators . Detritivores and Decomposers Detritivores and decomposers make up the last part of food chains . Detritivores are organisms that eat nonliving plant and animal  remains . For example,  scavengers such as vultures eat dead animals. Dung beetles eat animal  feces . Decomposers , like fungi and bacteria , complete the food chain . Decomposers turn  organic wastes , such as  decaying plants , into inorganic materials, such as nutrient -rich soil. They complete the cycle of life, returning nutrients to the soil or oceans for use by autotrophs . This starts a whole new series of food chains . Food Chains Food webs connect many different food chains , and many different trophic levels . Food webs can support food chains that are long and complicated, or very short. For example, grass in a forest clearing produces its own food through photosynthesis . A rabbit eats the grass. A fox eats the rabbit. When the fox dies, decomposers such as worms and mushrooms break down its body, returning it to the soil where it provides nutrients for plants like grass. This short food chain is one part of the forest 's food web . Another food chain in the same ecosystem might involve completely different organisms. A caterpillar may eat the leaves of a tree in the forest . A bird such as a sparrow may eat the caterpillar. A snake may then prey on the sparrow. An eagle, an apex predator , may prey on the snake. Yet another bird, a vulture, consumes the body of the dead eagle. Finally, bacteria in the soil decompose the remains . Algae and plankton are the main producers in marine ecosystems . Tiny shrimp called  krill  eat the microscopic plankton. The largest animal on Earth, the blue whale, preys on thousands of tons of krill every day. Apex predators such as orcas prey on blue whales. As the bodies of large animals such as whales sink to the seafloor, detritivores such as worms break down the material. The nutrients released by the decaying flesh provide chemicals for algae and plankton to start a new series of food chains . Biomass Food webs are defined by their  biomass . Biomass is the energy in living organisms. Autotrophs , the producers in a food web , convert the sun's energy into biomass . Biomass decreases with each trophic level . There is always more biomass in lower trophic levels than in higher ones. Because biomass decreases with each trophic level , there are always more autotrophs than herbivores in a healthy food web . There are more herbivores than carnivores . An ecosystem cannot support a large number of omnivores without supporting an even larger number of herbivores , and an even larger number of autotrophs . A healthy food web has an  abundance  of autotrophs , many herbivores , and relatively few carnivores and omnivores . This balance helps the ecosystem maintain and  recycle   biomass . Every link in a food web is connected to at least two others. The biomass of an ecosystem depends on how balanced and connected its food web is. When one link in the food web is threatened, some or all of the links are weakened or  stressed . The ecosystems biomass   declines . The loss of plant life usually leads to a decline in the herbivore population, for instance. Plant life can decline due to  drought , disease, or human activity. Forests are cut down to provide  lumber  for construction. Grasslands are paved over for shopping malls or parking lots. The loss of biomass on the second or third trophic level can also put a food web out of balance. Consider what may happen if a  salmon run  is  diverted . A salmon run is a river where salmon swim. Salmon runs can be diverted by  landslides and  earthquakes , as well as the construction of  dams and  levees . Biomass is lost as salmon are cut out of the rivers. Unable to eat salmon, omnivores like bears are forced to rely more heavily on other food sources, such as ants. The area's ant population shrinks. Ants are usually scavengers and detritivores , so fewer nutrients are broken down in the soil. The soil is unable to support as many autotrophs , so biomass is lost. Salmon themselves are predators of insect larvae and smaller fish. Without salmon to keep their population in check,  aquatic  insects may  devastate  local plant communities. Fewer plants survive , and biomass is lost. A loss of organisms on higher trophic levels , such as carnivores , can also disrupt a food chain . In  kelp forests , sea urchins are the primary consumer of kelp . Sea otters prey on urchins. If the sea otter population shrinks due to disease or hunting, urchins devastate the kelp forest . Lacking a community of producers , biomass   plummets . The entire kelp forest disappears. Such areas are called  urchin barrens . Human activity can reduce the number of predators. In 1986, officials in Venezuela dammed the Caroni River, creating an  enormous  lake about twice the size of Rhode Island. Hundreds of hilltops turned into islands in this lake. With their habitats reduced to tiny islands, many terrestrial predators weren’t able to find enough food. As a result, prey animals like howler monkeys, leaf-cutter ants, and iguanas flourished. The ants became so numerous that they destroyed the rainforest , killing all the trees and other plants . The food web surrounding the Caroni River was destroyed. Bioaccumulation Biomass declines as you move up through the trophic levels . However, some types of materials, especially  toxic  chemicals, increase with each trophic level in the food web . These chemicals usually collect in the  fat  of animals. When an herbivore eats a plant or other autotroph that is covered in  pesticides , for example, those pesticides are stored in the animal’s fat . When a carnivore eats several of these herbivores , it takes in the pesticide chemicals stored in its prey . This process is called  bioaccumulation . Bioaccumulation happens in aquatic ecosystems too.  Runoff  from  urban areas or  farms can be full of  pollutants . Tiny producers such as algae , bacteria , and seagrass absorb minute amounts of these pollutants . Primary consumers , such as sea turtles and fish, eat the seagrass . They use the energy and nutrients provided by the plants , but store the chemicals in their fatty tissue. Predators on the third trophic level , such as sharks or tuna, eat the fish. By the time the tuna is consumed by people, it may be storing a  remarkable  amount of bio accumulated toxins. Because of bioaccumulation , organisms in some polluted ecosystems are unsafe to eat and not allowed to be  harvested .  Oysters in the  harbor  of the United States' New York City, for instance, are unsafe to eat. The pollutants in the harbor   accumulate in its oysters , a filter feeder . In the 1940s and 1950s, a pesticide called  DDT  (dichloro-diphenyl-trichloroethane) was widely used to kill insects that spread diseases. During  World War II , the  Allies  used DDT to  eliminate typhus  in Europe, and to control  malaria  in the South Pacific. Scientists believed they had discovered a miracle drug. DDT was largely responsible for eliminating malaria in places like Taiwan, the Caribbean, and the Balkans . Sadly, DDT bio accumulates in an ecosystem and causes damage to the environment. DDT accumulates in soil and water. Some forms of DDT decompose slowly. Worms, grasses, algae , and fish accumulate DDT . Apex predators , such as eagles, had high amounts of DDT in their bodies, accumulated from the fish and small mammals they prey on. Birds with high amounts of DDT in their bodies lay eggs with extremely thin shells. These shells would often break before the baby birds were ready to hatch. DDT was a major reason for the decline of the bald eagle, an apex predator that feeds primarily on fish and small rodents. Today, the use of DDT has been restricted. The food webs of which it is a part have recovered in most parts of the country.

Lost Energy Biomass shrinks with each trophic level. That is because between 80% and 90% of an organism's energy, or biomass, is lost as heat or waste. A predator consumes only the remaining biomass.

A Million to One Marine food webs are usually longer than terrestrial food webs. Scientists estimate that if there are a million producers (algae, phytoplankton, and sea grass) in a food web, there may only be 10,000 herbivores. Such a food web may support 100 secondary consumers, such as tuna. All these organisms support only one apex predator, such as a person.

Out for Blood One of the earliest descriptions of food webs was given by the scientist Al-Jahiz, working in Baghdad, Iraq, in the early 800s. Al-Jahiz wrote about mosquitoes preying on the blood of elephants and hippos. Al-Jahiz understood that although mosquitoes preyed on other animals, they were also prey to animals such as flies and small birds.

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Food Web: Concept and Applications

Introduction

There are two types of food chains: the grazing food chain, beginning with autotrophs, and the detrital food chain, beginning with dead organic matter (Smith & Smith 2009). In a grazing food chain, energy and nutrients move from plants to the herbivores consuming them, and to the carnivores or omnivores preying upon the herbivores. In a detrital food chain, dead organic matter of plants and animals is broken down by decomposers, e.g., bacteria and fungi, and moves to detritivores and then carnivores.

Food web offers an important tool for investigating the ecological interactions that define energy flows and predator-prey relationship (Cain et al. 2008). Figure 1 shows a simplified food web in a desert ecosystem. In this food web, grasshoppers feed on plants; scorpions prey on grasshoppers; kit foxes prey on scorpions. While the food web showed here is a simple one, most feed webs are complex and involve many species with both strong and weak interactions among them (Pimm et al. 1991). For example, the predators of a scorpion in a desert ecosystem might be a golden eagle, an owl, a roadrunner, or a fox.

The idea to apply the food chains to ecology and to analyze its consequences was first proposed by Charles Elton (Krebs 2009). In 1927, he recognized that the length of these food chains was mostly limited to 4 or 5 links and the food chains were not isolated, but hooked together into food webs (which he called "food cycles"). The feeding interactions represented by the food web may have profound effects on species richness of community, and ecosystem productivity and stability (Ricklefs 2008).

Types of Food Webs

Applications of food webs, food webs are constructed to describe species interactions (direct relationships)..

The fundamental purpose of food webs is to describe feeding relationship among species in a community. Food webs can be constructed to describe the species interactions. All species in the food webs can be distinguished into basal species (autotrophs, such as plants), intermediate species (herbivores and intermediate level carnivores, such as grasshopper and scorpion) or top predators (high level carnivores such as fox) (Figure 1).

These feeding groups are referred as trophic levels. Basal species occupy the lowest trophic level as primary producer. They convert inorganic chemical and use solar energy to generate chemical energy. The second trophic level consists of herbivores. These are first consumers. The remaining trophic levels include carnivores that consume animals at trophic levels below them. The second consumers (trophic level 3) in the desert food web include birds and scorpions, and tertiary consumers making up the fourth trophic level include bird predators and foxes. Grouping all species into different functional groups or tropic levels helps us simplify and understand the relationships among these species.

Food webs can be used to illustrate indirect interactions among species.

Indirect interaction occurs when two species do not interact with each other directly, but influenced by a third species. Species can influence one another in many different ways. One example is the keystone predation are demonstrated by Robert Paine in an experiment conducted in the rocky intertidal zone (Cain et al. 2008; Smith & Smith 2009; Molles 2010). This study showed that predation can influence the competition among species in a food web. The intertidal zone is home to a variety of mussels, barnacles, limpets, and chitons (Paine 1969). All these invertebrate herbivores are preyed upon by the predator starfish Pisaster (Figure 3). Starfish was relatively uncommon in the intertidal zone, and considered less important in the community. When Paine manually removed the starfish from experimental plots while leaving other areas undisturbed as control plots, he found that the number of prey species in the experimental plots dropped from 15 at the beginning of the experiment to 8 (a loss of 7 species) two years after the starfish removal while the total of prey species remained the same in the control plots. He reasoned that in the absence of the predator starfish, several of the mussel and barnacle species (that were superior competitors) excluded the other species and reduced overall diversity in the community (Smith & Smith 2009). Predation by starfish reduced the abundance of mussel and opened up space for other species to colonize and persist. This type of indirect interaction is called keystone predation.

Food webs can be used to study bottom-up or top-down control of community structure.

Top-down control occurs when the population density of a consumer can control that of its resource, for example, predator populations can control the abundance of prey species (Power 1992). Under top-down control, the abundance or biomass of lower trophic levels depends on effects from consumers at higher trophic levels. A trophic cascade is a type of top-down interaction that describes the indirect effects of predators. In a trophic cascade, predators induce effects that cascade down the food chain and affect biomass of organisms at least two links away (Ricklefs 2008). Nelson Hairston, Frederick Smith and Larry Slobodkin first introduced the concept of top-down control with the frequently quoted "the world is green" proposition (Power 1992; Smith & Smith 2009). They proposed that the world is green because carnivores depress herbivores and keep herbivore populations in check. Otherwise, herbivores would consume most of the vegetation. Indeed, a bird exclusion study demonstrated that there were significantly more insects and leaf damage in plots without birds compared to the control (Marquis & Whelan 1994).

Food webs can be used to reveal different patterns of energy transfer in terrestrial and aquatic ecosystems.

As a diagram tool, food web has been approved to be effective in illustrating species interactions and testing research hypotheses. It will continue to be very helpful for us to understand the associations of species richness/diversity with food web complexity, ecosystem productivity, and stability.

References and Recommended Reading

Cain, M. L., Bowman, W. D. & Hacker, S. D. Ecology . Sunderland MA: Sinauer Associate Inc. 2008.

Cebrian, J. Patterns in the fate of production in plant communities. American Naturalist 154 , 449-468 (1999)

Cebrian, J. Role of first-order consumers in ecosystem carbon flow. Ecology Letters 7 , 232-240 (2004)

Elton, C. S. Animal Ecology . Chicago, MI: University of Chicago Press, 1927, Republished 2001.

Knight, T. M., et al. Trophic cascades across ecosystems. Nature 437 , 880-883 (2005)

Krebs, C. J. Ecology 6 th ed. San Francisco CA: Pearson Benjamin Cummings, 2009.

Marquis, R. J. & Whelan, C. Insectivorous birds increase growth of white oak through consumption of leaf-chewing insects. Ecology 75 , 2007-2017 (1994)

Molles, M. C. Jr. Ecology: Concepts and Applications 5 th ed. New York, NY: McGraw-Hill Higher Education, 2010.

Paine, R. T. The Pisaster-Tegula interaction: Prey parches, predator food preferences and intertide community structure. Ecology 60 , 950-961 (1969)

Paine, R. T. Food web complexity and species diversity. The American Naturalist 100 , 65-75 (1966)

Paine, R. T. Food webs: Linkage, interaction strength and community infrastructure. Journal of Animal Ecology 49 , 667-685 (1980)

Pimm, S. L., Lawton, J. H. & Cohen, J. E. Food web patterns and their consequences. Nature 350 , 669-674 (1991)

Power, M. E. Top-down and bottom-up forces in food webs: do plants have primacy? Ecology 73 , 733-746 (1992)

Schoender, T. W. Food webs from the small to the large. Ecology 70 , 1559-1589 (1989)

Shurin, J. B., Gruner, D. S. & Hillebrand, H. All wet dried up? Real differences between aquatic and terrestrial food webs. Proc. R. Soc. B 273 , 1-9 (2006) doi:10.1098/rspb.2005.3377

Smith, T. M. & Smith, R. L. Elements of Ecology 7 th ed. San Francisco CA: Pearson Benjamin Cummings, 2009.

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9.3: Food Chains and Food Webs

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Trophic Interactions

Trophic interactions occur when one organism feeds on another. Trophic interreactions strongly influence the structure of communities as the populations of one species (a predator) can influence population sizes of other species (prey). The three main types of trophic interactions that influence community structure are predation (Figure \(\PageIndex{1}\)) and herbivory. During these interactions, one species benefits by gaining food at the expense of the other, which either dies or loses nutrients, tissues, or organs (such as leaves). Trophic interactions involve the flow of energy, and the trophic interactions in a community can be represented by food chains and food webs .

Definition: Trophic Level

A species’ trophic level is their position in the food chain or web. At the bottom of the food web are autotrophs, also known as producers. The next level is herbivores (primary consumers), these species feed on producers for their energy source. Herbivores are consumed by omnivores or carnivores. These species are secondary and tertiary consumers. Additional levels to the trophic scale come when smaller omnivores or carnivores are eaten by larger ones. At the top of the food web is the apex predator, this animal species is not consumed by any other in the community.

Food Chains

A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another; the levels in the food chain are producers, primary consumers, higher-level consumers, and finally decomposers. These levels are used to describe ecosystem structure and dynamics. There is a single path through a food chain. Each organism in a food chain occupies a specific trophic level (energy level), its position in the food chain or food web.

In many ecosystems, the base, or foundation, of the food chain consists of photosynthetic organisms (plants or phytoplankton), which are called producers . The organisms that consume the producers are herbivores: the primary consumers . Secondary consumers are usually carnivores that eat the primary consumers. Tertiary consumers are carnivores that eat other carnivores. Higher-level consumers feed on the next lower trophic levels, and so on, up to the organisms at the top of the food chain: the apex consumers. In the Lake Ontario food chain, shown in Figure \(\PageIndex{2}\), the Chinook salmon is the apex consumer at the top of this food chain.

Trophic Level Transfer Efficiency

One major factor that limits the number of steps in a food chain is energy. Energy is lost at each trophic level and between trophic levels as heat and in the transfer to decomposers (Figure \(\PageIndex{3}\)). Only a fraction of the energy captured by one trophic level is assimilated into biomass, which makes it available to the next trophic level. Assimilation is the biomass of the present trophic level after accounting for the energy lost due to incomplete ingestion of food, energy used to conduct work by that trophic level, and energy lost as waste. Incomplete ingestion refers to the fact that some consumers eat only a part of their food. For example, when a lion kills an antelope, it will eat everything except the hide and bones. The lion is missing the energy-rich bone marrow inside the bone, so the lion does not make use of all the calories its prey could provide.

The trophic level transfer efficiency is the percentage of biomass or energy at one trophic level that is transferred to the next. On average trophic level transfer efficiency is only about 10%. Thus, after a limited number of trophic energy transfers, the amount of energy remaining in the food chain may not be great enough to support viable populations at yet a higher trophic level. As a result most communities are limited to 4 or 5 trophic levels.

There is a one problem when using food chains to describe most ecosystems. Even when all organisms are grouped into appropriate trophic levels, some of these organisms can feed on more than one trophic level; likewise, some of these organisms can also be fed on from multiple trophic levels. In addition, species feed on and are eaten by more than one species. In other words, the linear model of ecosystems, the food chain, is a hypothetical, overly simplistic representation of ecosystem structure. A holistic model—which includes all the interactions between different species and their complex interconnected relationships with each other and with the environment—is a more accurate and descriptive model for ecosystems. A food web is a concept that accounts for the multiple trophic (feeding) interactions between each species and the many species it may feed on, or that feed on it. In a food web, the several trophic connections between each species and the other species that interact with it may cross multiple trophic levels. The matter and energy movements of virtually all ecosystems are more accurately described by food webs (Figure \(\PageIndex{4}\)).

A comparison of the two types of structural ecosystem models shows strength in both. Food chains are more flexible for analytical modeling, are easier to follow, and are easier to experiment with, whereas food web models more accurately represent ecosystem structure and dynamics, and data can be directly used as input for simulation modeling.

Two general types of food webs are often shown interacting within a single ecosystem. A grazing food web has plants or other photosynthetic organisms at its base, followed by herbivores and various carnivores. A detrital food web consists of a base of organisms that feed on decaying organic matter (dead organisms), including decomposers (which break down dead and decaying organisms) and detritivores (which consume organic detritus). These organisms are usually bacteria, fungi, and invertebrate animals that recycle organic material back into the biotic part of the ecosystem as they themselves are consumed by other organisms. As ecosystems require a method to recycle material from dead organisms, grazing food webs have an associated detrital food web. For example, in a meadow ecosystem, plants may support a grazing food web of different organisms, primary and other levels of consumers, while at the same time supporting a detrital food web of bacteria and fungi feeding off dead plants and animals. Simultaneously, a detrital food web can contribute energy to a grazing food web, as when a robin eats an earthworm.

Top Down vs Bottom Up Control

Changes to one of the levels in the food chain can result in changes in other levels which scientists call a trophic cascade . These cascades can affect levels below that altered level or levels above the altered level. We categorize these directional cascades as top-down or bottom-up control, which simply means the changes to the food chain occurred at either the top trophic level or the bottom trophic level and then impacted the other levels up or down the food chain.

In the top-down contro l, the populations of the organisms lower trophic levels (bottom of the pyramid) are controlled by the organisms at the top. This approach is also called the predator-controlled food web of an ecosystem. 

For instance, imagine a simplified ecosystem where there are just 3 tropic levels: plants, an herbivore, and a carnivores. The presence of the carnivore keeps the herbivore population in check. If there were no carnivores in this ecosystem, then the herbivore population would rapidly increase. As a result, all the plants would be eaten. When almost all the plants are eaten by the huge, unsustainable population of herbivores, there is no food. So, that population of herbivores would eventually starve to death and the ecosystem would collapse. Thus, the carnivores keep the herbivore population in check, so that the plants are not overeaten and the ecosystem will continue to function.

The bottom-up control is driven by the presence or absence of the producers in the ecosystem. Changes in their population will affect the population of all the species in the food web, and thus, the ecosystem. This approach is also called the resource-controlled (or food-limited) food web of an ecosystem.

In the same simplified example ecosystem above, let us consider the reverse scenario. What if the population of plants in the ecosystem dwindled to extremely low numbers? Then, the herbivores would have less food to feed on. Consequently, their population would shrink to reflect the lack of food. When the population of herbivores decreases, the carnivores will also automatically face a shortage of food. The carnivore population would also decline. If plants disappeared altogether, then the ecosystem would collapse.

Does an ecosystem have to choose to be either top-down or bottom-up?

No. In most ecosystems, studies have shown that these two approaches are not mutually exclusive. For example, in marine ecosystems that were initially thought to be purely bottom-up, there have been periods of top-down control due to extraction of large predators through fishing.

Consequences of Food Webs: Biological Magnification

Definition: biomagnification.

Biomagnification is the increasing concentration of persistent, toxic substances in organisms at each successive trophic level. These are substances that are fat soluble, not water soluble, and are stored in the fat reserves of each organism.

One of the most important consequences of ecosystem dynamics in terms of human impact is biomagnification. Many substances have been shown to biomagnify, including classical studies with the pesticide dichlorodiphenyltrichloroethane (DDT), which were described in the 1960s bestseller, Silent Spring by Rachel Carson. DDT was a commonly used pesticide before its dangers to apex consumers, such as the bald eagle, became known. In aquatic ecosystems, organisms from each trophic level consumed many organisms in the lower level, which caused DDT to increase in birds (apex consumers) that ate fish. Thus, the birds accumulated sufficient amounts of DDT to cause fragility in their eggshells. This effect increased egg breakage during nesting and was shown to have devastating effects on these bird populations. The use of DDT was banned in the United States in the 1970s.

Other substances that biomagnify are polychlorinated biphenyls (PCB), which were used as coolant liquids in the United States until their use was banned in 1979, and heavy metals, such as mercury, lead, and cadmium. These substances are best studied in aquatic ecosystems, where predatory fish species accumulate very high concentrations of toxic substances that are at quite low concentrations in the environment and in producers. As illustrated in a study performed by the NOAA in the Saginaw Bay of Lake Huron of the North American Great Lakes (Figure \(\PageIndex{7}\)), PCB concentrations increased from the producers of the ecosystem (phytoplankton) through the different trophic levels of fish species. The apex consumer, the walleye, has more than four times the amount of PCBs compared to phytoplankton. Also, based on results from other studies, birds that eat these fish may have PCB levels at least one order of magnitude higher than those found in the lake fish.

Other concerns have been raised by the biomagnification of heavy metals, such as mercury and cadmium, in certain types of seafood. The United States Environmental Protection Agency recommends that pregnant women and young children should not consume any swordfish, shark, king mackerel, or tilefish because of their high mercury content. These individuals are advised to eat fish low in mercury: salmon, shrimp, pollock, and catfish. Biomagnification is a good example of how ecosystem dynamics can affect our everyday lives, even influencing the food we eat.

Attributions

This page is a modified derivative of:

• 20.1: Energy Flow through Ecosystems via OpenStax ; license CC BY 4.0 .

Food Chain and Food Web

• Producers - Plants are producers. This is because they produce energy for the ecosystem. They do this because they absorb energy from sunlight through photosynthesis . They also need water and nutrients from the soil, but plants are the only place where new energy is made.
• Consumers - Animals are consumers. This is because they don't produce energy, they just use it up. Animals that eat plants are called primary consumers or herbivores. Animals that eat other animals are called secondary consumers or carnivores. If a carnivore eats another carnivore, it is called a tertiary consumer. Some animals play both roles, eating both plants and animals. They are called omnivores.
• Decomposers - Decomposers eat decaying matter (like dead plants and animals). They help put nutrients back into the soil for plants to eat. Examples of decomposers are worms, bacteria, and fungi.
• grass = producer
• zebra = primary consumer
• lion = secondary consumer

• Level 1: Plants (producers)
• Level 2: Animals that eat plants or herbivores (primary consumers)
• Level 3: Animals that eat herbivores (secondary consumers, carnivores)
• Level 4: Animals that eat carnivores (tertiary consumers, carnivores)
• Level 5: Animals at the top of the food chain are called apex predators. Nothing eats these animals.
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Bio Differences

Learn the Biological Differences

Difference Between Food Chain and Food Web

August 23, 2017 by Rachna C 6 Comments

Both the food chain and food web are the systems that portray the actual energy flow process in an ecosystem. The existence of our earth relies on this energy circulation between different organisms.

The food chain is a simple representation that illustrates the linear passage of nutrients and energy. The producers initiate this energy flow and it ends with the apex consumers. In contrast, the food web is a detailed presentation that depicts the interconnection between several food chains.

In a food chain, one trophic level’s organism solely depends upon the single preceding trophic level. Here, every particular organism has its specified consumer. Thus, if any of the organisms is removed, it might disturb the whole energy flow. For this reason, the chances of instability in the environment increase.

Whereas, in food webs, one trophic level never completely gets dependent on a single species. Here, the one organism serves multiple roles, i.e., of a producer or a consumer. Thus, the removal of a species never causes significant damage to the ecosystem.

This section will emphasize key differences between the food chain and the food web.

Content: Food Chain Vs Food Web

Comparison chart.

• How does Energy Flow in the Ecosystem?
• What is a Food Chain?

What is a Food Web?

• Key Differences

How does the energy flow in the ecosystem?

Energy is the ultimate need of all living organisms on the earth. The absence of energy will cease all the metabolic, physiological and physiochemical activities of the living world. The energy constantly flows from one trophic level to another in the ecosystem. This proportion of energy that circulates defines the energy flow or calorific flow.

For any ecosystem, the sun serves as the primary energy source that possesses 100 % energy. The sun supplies about 85 % of its energy to the plants. Of which, plants only absorb 1-2% of the energy to perform photosynthesis.

Ten % law : This law proposes that a large proportion of energy deteriorates in the form of heat at every trophic level. And only 10 % of the actual is transferred to the subsequent trophic level.

What is a Food chain?

The food chain is the most elementary and uncomplicated way to represent the energy flow. It is a linear pathway that manifests the movement of nutrients and energy from one trophic level to the next.

Almost all the food chains begin with the producers that are at the basal level. These producers are generally green plants that are capable of performing photosynthesis.

Sun provides its solar energy to the plants which they convert into chemical energy. This chemical energy is then transmitted to the succeeding trophic level. And this way, the flow of energy goes on.

Definition of Food Chain

We can define the food chain as:

“A simple sequence of energy flow from lower trophic levels to the higher trophic levels by the repeated events of eating and being eaten”.

Characteristics of Food Chain

• The food chain is an uncomplicated pathway that summarizes who eats whom very simply.
• The autotrophs or producers always occupy the first trophic level in the food chain.
• A single food chain may consist of 4-6 trophic levels . These levels consume the energy as per the hierarchic division.
• At every level, some amount of potential energy is wasted as heat. It implies that the fewer the number of trophic levels, the more efficient the energy transfer will be . Thereby, shorter food chains generate greater biomass.
• In this type of energy flow, a single organism or a species cannot perform many functions. That means they cannot dwell at multiple trophic levels simultaneously. For example: If a goat is eating grass and a tiger is eating a goat, then the goat will only ever be below the tiger, and the grass will always be under the goat.
• Since one organism survives wholly and solely on another, thus removal of a single species will cause a severe disturbance in the ecosystem. Due to this reason, there is a perpetual risk of instability in the environment.

For example, if the tiger only survives over deer, then the decrease in the number of deers will immensely influence the tiger population.

Types of Food Chains

There are three types of food chains:

• Predator Food Chain : This is a typical food chain. It begins with plants and continues from lower predators to the higher. This type of food chain involves autotrophs, herbivores, carnivores and omnivores at 1st, 2nd, 3rd and 4th trophic levels. Here, the predator size is increased at every succeeding level ranging from smallest to biggest.

The food web is a complex representation of the energy flow that summarizes all kinds of basic food chains. It portrays the actually occurring interactions among the various species in the real world.

It is a more realistic and dynamic tool to reveal the several different approaches by which the biotic factors stay connected. The food web is not an isolated or linear sequence in any ecosystem. Instead, it is interconnected and interlocked and has multiple trophic levels at the same time.

Definition of Food Web

We can define the food web as:

“A complex zigzag representation that exhibits the energy circulation between the multiple trophic levels all at once”.

Characteristics of Food Web

• The food web creates an intricate but accurate network between already existing food chains in the ecosystem.
• Here, a single species can perform different roles and can be present at multiple trophic levels. Thus, it is a more precise display of what really occurs in the environment.
• It provides the optimum conditions for any species to enhance adaptability and competitiveness . This increases the organism’s probability of survival.
• The food web is exceptionally stable as no one organism solely relies only on one species for food. Thus, the elimination of one organism will not cause a severe disturbance in the operations of the food web.
• The food web is complicated due to the presence of variety in taste, preference, availability, and many related factors. It doesn’t obligate any organism to follow a strict diet completely. For example, the tigers do not consume aquatic species like fish, crabs in the forest. But in Sundarbans, the tigers have adapted themselves to survive over the easily available aquatic fauna.
• Food seasonality also influences the working of the food chain.
• Food webs consist of some particular species that are keystone species . We refer to these top predators as apex predators.

Food seasonality

It infers the availability of biotic communities on the basis of abiotic factors like temperature, photoperiod, etc. For example, Certain species are seasonal specialists. They decouple themselves from the food chain for their survival. Like in winters, migrating to different places arresting their metabolic action through

• Hibernation

Or through aestivation in summers. This food seasonality impacts the other group of species as they are now bound to feed on the available sources.

Keystone species

These are certain species that decide the stability and sustainability of the ecosystem. Elimination of these organisms might lead to the collapse of the food web.

For example, Grizzly bears are among the top predators in forest ecosystems. The collapse in their number will severely impact the food web.

Importance of Food Web

• The food webs make it very convenient to understand interactions and interrelations among the various species.
• We can easily define the energy circulation within the ecosystem with the help of the food web.
• It is helpful in understanding the disastrous consequences of the entry of toxins or any poisonous elements in the food chain.
• The food web also exhibits the natural selection process very efficiently. We can monitor the influence of environmental problems on natural flora and fauna with the food web.

For example

• Scarcity of food
• Overhunting
• Urbanization
• Population explosion

Key Differences Between Food Chain and Food Web

Given below are the important point which differentiates the Food Chain and Food Web:

• The food chain is a simple pathway that defines energy flow from lower to higher trophic levels. Whereas, the food web is a complex representation of the energy flow between the multiple trophic levels.
• In the food chain, a single series shows the interaction between the organisms of succeeding trophic levels. In contrast, there are numerous food chains summarized in a food web.
• One group of organisms strictly depend on the other. And thus, disruption in a single trophic level might collapse the whole food chain. In the food web, there is a multi-dependency among the trophic level. Thus, there will be no significant damage to the entire structure of the food web.
• One trophic level of a food chain relies on the preceding trophic level for food and energy. While in the food web, a single trophic level can depend on many other trophic levels for its food.
• There is always a risk of instability and unsustainability in the case of the food chain. But there is an immense amount of stability and sustainability in the food web.
•  A typical food chain comprises about 4-6 trophic levels. In contrast, a food web constitutes several trophic levels.

Food chain and food web are ecological food maps that define the direction of energy flow. Both of them serve the purpose of understanding the relations between the biotic community. These concepts determine the real picture of the interaction in the environment. But their use might slightly vary as per your need.

You should study a food chain if you are trying to gain basic knowledge about the energy flow. Whereas, if you want to learn about the complex relations among the multiple trophic levels you should study a food web.

More Comparisons:

• Difference Between Ecosystem and Community
• Difference Between Producers and Consumers
• Difference Between Habitat and Niche
• Difference Between Mutualism, Commensalism and Parasitism
• Difference Between Abiotic and Biotic Factors

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• Biology Difference Between

Difference Between Food Chain And Food Web

Before we look at the difference Between Food Chain and Food Web, let’s understand what a food chain is: A food chain is a linear flow of energy and nutrients from one organism to another.

Each organism sits at a particular trophic level; for instance, the primary producers, such as grass, sit at trophic level 1, and the apex predators sit at trophic level 4 or 5.

A food web can be termed as the combination of many different food chains and the relationship between organisms .

The most important differences Between Food Chain and Food Web are summarized below:

To Summarize

A food chain is a basic network that shows the linear flow of nutrients and energy from one trophic level to another. A food web is a multitude of interconnected food chains at many trophic levels. Furthermore, a food web accurately represents all the various food chains that exist in an ecosystem .

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Food chain: useful essay on food chain (463 words).

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Food Chain: Useful Essay on Food Chain!

In nature, we generally distinguish two general types of food chains: of razing food chain and detritus food chain. The Grazing food chain starts from the living green plants, goes to grazing herbivores (that feed on living plant materials with their predators), and on to carnivores (animal eaters).

Ecosystems with such type of food chain are directly dependent on an influx of solar radiation. This type of chain thus depends on autotrophic energy capture and the movement of this captured energy to herbivores.

Most of the ecosystems in nature follow this type of food chain. From energy standpoint, these chains are very important. The phytoplankton’s – zooplanktons – fish sequence or the grasses – rabbit- fox sequence are the examples of grazing food chain.

The Detritus Food chain goes from dead organic matter into microorganisms and then to organisms feeding on detritus (detritivores) 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. A good example of a detritus food chain is based on mangrove leaves.

All the animals are detritus consumers. These detritivores are the key group of small animals, comprising only a few species but very large number of individuals. They ingest large amounts of the vascular plant detritus. These animals are in turn eaten by some minnows and small game fish etc. that is the small carnivores, which in turn serve as the main food for larger game fish and fish eating birds which are the large (top) carnivores.

The mangroves considered generally as of less economic value make a substantial contribution to the food chain that supports the fisheries, an important economy in that region. Similarly detritus from sea grasses, salt marsh grasses and seaweeds support fisheries in many estuarine areas.

Thus the detritus food chain ends up in a manner similar to the grazing food chain (big fish eat little fish), but the way in which the two chains begin is quite different. In detritus chain, the detritus consumers, in contrast to grazing herbivores, are a mixed group in terms of trophic levels.

These include herbivores, omnivores and primary carnivores. As a group, the detritus feeders obtain some of their energy directly from plant material, most of it secondarily from microorganisms, and some territorially through carnivores (for example by eating protozoa or other small invertebrates that have fed or bacteria that have digested plant material).

But under natural situations, system must always be self sufficient. In fact this type of food chain (detritus type) is simply a sub-component of another ecosystem. And, the above said two types of food chain in nature are indeed linked together belonging to the same ecosystem.

Related Articles:

• Food Chains: Useful notes on Food Chains (explained with diagram) | Ecology
• Food Chain: Short Notes on Concept and Types of Food Chain

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Red Lobster website lists 87 locations 'temporarily closed' in 27 states: See full list

Red Lobster has abruptly closed dozens of restaurants across the country.

A look at the restaurant chain's website reveals 87 stores temporarily closed across 27 states, with some of them having their kitchen equipment up for auction on an online restaurant liquidator.

The liquidator, TAGeX Brands, announced Monday it is auctioning off equipment this week from 48 locations that have closed. The website says auctions are live and will end periodically on Thursday, and that each winner will receive the "entire contents of the Red Lobster location they bid on."

USA TODAY reached out to Red Lobster on Tuesday and did not get a response prior to publication.

Here's what we know about the closures, including where they're happening and why these restaurants are closing.

Red Lobster closures: Red Lobster abruptly closes dozens of restaurant locations around US, preparing to liquidate

McDonald's $5 deals: McDonald’s is focused on affordability. What we know after reports of $5 meal deals.

Closed Red Lobster locations

Each of these restaurants are currently listed as temporarily closed on the website:

• Rohnert Park
• Wheat Ridge
• Altamonte Springs
• Daytona Beach Shores
• Gainesville
• Jacksonville (Commerce Center Drive)  
• Jacksonville (Baymeadows Road)  
• Jacksonville (City Station Drive)
• Orlando (E. Colonial Dr.)
• Orlando (W. Colonial Dr.)
• Orlando (Golden Sky Lane) 
• Tampa (East Busch Blvd.)
• Tampa (Palm Pointe Dr.)
• Bloomingdale
• Indianapolis (N. Shadeland Ave.)
• Kansas City
• Bossier City
• Gaithersburg
• Silver Spring

Mississippi

• Jefferson City
• Bridgewater
• East Brunswick
• Lawrenceville
• Poughkeepsie
• Stony Brook
• Williamsville

North Carolina

• Rocky Mount

North Dakota

• Grand Forks
• Oklahoma City

Pennsylvania

South carolina.

• Myrtle Beach
• Dallas (E. Technology Blvd.)
• Dallas (Vantage Point Dr.)
• Lake Jackson
• Colonial Heights
• Newport News
• Williamsburg

Red Lobster considered filing for bankruptcy in April

The seafood chain considered filing for Chapter 11 bankruptcy last month in an effort to restructure its debt,  according to Bloomberg .

The company had been getting advice from law firm King & Spalding as it looked to shed some long-term contracts and renegotiate leases, Bloomberg reported, noting that Red Lobster's cash flows had been weighed down by leases and labor costs, among other issues.

Red Lobster suffered big losses with 'Ultimate Endless Shrimp' promotion

In 2023, the seafood chain's " Ultimate Endless Shrimp " deal became more popular than expected, inadvertently becoming a key factor in a $11 million loss in the third quarter.

The limited-time promotional deal, in which guests picked two types of shrimp to enjoy nonstop for $20, landed a permanent spot on Red Lobster menus in June. Red Lobster's parent company, Thai Union Group, said in November 2023 that the chain was headed toward a $20 million loss for 2023. Now the endless shrimp deal costs $25.

Thai Union Group CFO Ludovic Regis Henri Garnier said in an earnings report call that the company was aware the initial price for the endless-shrimp deal was cheap. The offer was intended to draw customers into restaurants, but orders exceeded expectations, he said.

"We wanted to boost our traffic, and it didn't work," Garnier told investors in November 2023, according to  Restaurant Business Magazine . "We want to keep it on the menu. And of course we need to be much more careful regarding what are the entry points and what is the price point we are offering for this promotion."

Chris Sims is a digital content producer at Midwest Connect Gannett. Follow him on Twitter:  @ChrisFSims .

Gabe Hauari is a national trending news reporter at USA TODAY. You can follow him on X  @GabeHauari  or email him at [email protected].