Question

Compare the ability of a food chain and a food web to describe the trophic interactions between organims in an ecosystem

Answer 1

Food chain

• In this the energy is passed from one member to another, in which one member becomes food of the other member.
• A food chain contains producers, herbivores, primary and secondary carnivores and top carnivores.
• In which producers constitute the first trophic level- because they are the only ones that can manufacture organic food( various proteins, vitamins,carbohydrates, fats etc..) from inorganic raw materials( light)(using various enzymes and chlorophyll).- so they are also called base of a food chain. They are also considered as transducers because of their ability to change light energy from sun into chemical energy. Some energy made by them are used for their own maintenance.
• Primary Consumer or Herbivore- They depend on plants for getting energy and food. Include- some insects, rabbit, deer, elephant, zooplankton etc..They are called key industrial animals (because they are capable of converting plant biomass into animal matter)
• Secondary Consumer or Primary Carnivore- they derive their food and energy from predating on herbivores. Example- several birds, fishes, jackal, frog etc...
• Teritary Consumer or Secondary Carnivore - they predate on primary carnivores for getting energy and food. Eg; wolf, snale etc..
• Top Carnivore- They predate on secondary cranivores , but won't become prey of any animals. They are much ferocious than any other animals in every groups, (listed above). Example - shark, crocodile, agle, lion , tiger etc..
• One example of Food Chain- Vegetation Insect Insectivorus Bird Hawk
• (In all level a part of food they consumed is used for deriving energy , that are needed for their metabolic activities)

Food Web   

• It is actually a network of many food chains, due to some interconnections at various trophic levels.In this different feeding connections are established beween different group of organisms.
• This takes into consideration - availability of food sources as compared to food chain- which is purely based on its preference.
• 3 types of food chains can be observed in food web.
• 1)Predator food chains - begins with vegetation- then small animals , then large animals
• 2)Parasitic Food chains - first large animals then to small animals
• 3)Saprophytic food chain - beginning from dead ones to microorganisms.
• In all together, Food web enables us to study about various inter-relations exists between various populations