Food Web: Characteristics, Types and Management

Key Concepts

• Food web
• Biomass
• Energy Flow Food Webs
• Types of Food webs
• Balanced Ecosystem

Food web: The network of the interrelated and interconnected food chains that include producers, consumers and decomposers, is called the food web. It follows just one path as animals find food. Example: A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass. 

Energy Movement 

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

Approximately 10% of the energy that is transferred from one trophic level to the next is converted to biomass.  

Biomass refers to the overall mass of an organism or the mass of all the organisms that exist at a given trophic level. Since organisms use up a certain part of their energy to move around a part of the energy consumed is stored as biomass.   

Characteristics of a Food Web:  

1. Unlike food chains, food webs are never straight. Instead, each food web is formed by the interlinking of food chains.  

2. A food web provides alternative pathways of food availability. For example, if a particular species of a producer is destroyed by a disease in the ecosystem, the herbivores of that area can feed on other species of producers. Similarly, Secondary consumers (e.g., predatory birds) may feed on rats or mice in the event of a decrease in the population of rabbits in that area on which they also commonly feed.  

3. Greater alternatives available in a food web make the ecosystem more stable.  

4. Food webs also help in checking the overpopulation of highly fecundive species of plants and animals.  

5. Food webs also help in ecosystem development. 

Different Types of Food web: 

Food webs exist in a variety of biomes. Because each habitat is unique, each food web is slightly different. There are an aquatic ecosystem, a terrestrial ecosystem, and a crossover of them, existing in a perfectly balanced state. Explore different plants, animals, and decomposers that can be found in deserts, savannas, forests, and marine environments. 

Desert 

A desert is a habitat with little water. Deserts are not all hot either. Some deserts are very cold. In the desert food web, you will find: 

• Producers: Cacti, bushes, acacias, flowers, brush 

• Primary Consumers: Insects, lizards, rodents 
• Secondary Consumers: Tarantulas, scorpions, lizards, snakes 
• Tertiary Consumers: Hawks, foxes 

Forest 

Forests have lots of trees and other plants. They are dense with lots of different vegetation for animals. Forest food web includes: 

• Producers: Plants, fruits, nuts, seeds, flowers 
• Primary Consumers: Deer, squirrels, frogs, birds, pikas 
• Secondary Consumers: Pine marten, jackrabbits, ravens, ringtails 
• Tertiary Consumers: Bobcats, mountain lions, coyotes 

Savanna 

A savanna biome has a lot of grass for animals to graze on. These habitats are found in Africa, Australia, and even South America. Savana Food web includes: 

• Producers: Star grass, oat grass, and acacia 
• Primary Consumers: Grasshoppers, ants, termites, warthogs, gazelle, impala, mice, wildebeest 
• Secondary Consumers: Pangolins, aardvarks, mongooses 
• Tertiary Consumers: Wild dogs, lions, cheetahs, caracals, servals, eagles 

Marine 

Underwater creatures like variety too. In a marine environment, examples of components we will find in the food web include: 

• Producers and Decomposers: Seagrass, seaweed, algae, plankton, bacteria 
• Primary Consumers: Turtles, damselfish, crab, shrimp 
• Secondary Consumers: Octopuses, triggerfish, squid, krill 

• Tertiary Consumers: Seagulls, penguins, elephant seals, whales 

Management of Food web: 

Food webs are easily unbalanced, especially if one population of organisms in the web dies or disappears. This may happen for a number of reasons, including:  

• Over–predation or hunting 
• Disease 

• Pollution 
• Use of pesticides 
• Lack of food (or other resources) 
• Emigration 

For example, if all the baboons were killed by hunters in the food web here, the leopard would have only the impala to eat. So, the impala population would decrease. The scorpion population may increase because of less predation by baboons, but if there are more scorpions, they will eat more locusts, reducing the locust population, and so on. 

Frequently asked questions 

1. What is a Biomass? 

Ans: Biomass refers to the overall mass of an organism or the mass of all the organisms that exist at a given trophic level. Since organisms use up a certain part of their energy to move around a part of the energy consumed is stored as biomass.   

2. What are the reasons that may affect the balance of a food web? 

Ans:  

• Over–predation or hunting  
• Disease  
• Pollution  
• Use of pesticides  
• Lack of food (or other resources)  
• Emigration 

3. What are the producers in a marine/aquatic ecosystem? 

Ans: In a marine ecosystem, the producers and decomposers are Seagrass, seaweed, algae, plankton, and bacteria. 

4. What are the tertiary consumers in a forest ecosystem? 

Ans: Bobcats, mountain lions, and coyotes.