 food web, first the contents, definition of food web, the grazing food web, the tritle food web, and the trophic levels in the food web or ecosystem, first the food web, food web say apparently if you are familiar with basically food web it is the complex network of food chains within the ecosystem through which the energy is traveling from bottom to the top. So in a food web simply we have, if we talk in the ecosystem that one animal is eating the other one is eating the third one is eating the fourth one, what is this overall we have is the food chain. In the ecosystem, any food chain is not isolated. Normally different food chains they are connected with each other, so when in an ecosystem there are many food chains, there are many food chains, they are connected with each other, they are connected with each other, so a network of food chains is formed, so what we have is a network and this overall network of food chains is called the food web, so it is called the food web, so food web, food chains are the food web of two basic categories, the one is grazing food chains, food webs and the second one is the detrital food web, so grazing food webs, grazing food web are those food webs in which the starting point they are green plants, these are not the food webs we have in which the food chains that are starting are green plants, grasses, what will we call these plants as food webs, they are the grazing food webs, now for example if we look at this, like grasses, grasses are eating insects, insects are eating frogs, so this is a food chain, the frog will eat snakes, the second food chain will be grasses, insects, insects will eat birds, birds will eat predator birds, so this will be the second food chain, similarly the same grasses are eating deer, the deer will eat lion, so this will be the third food chain, so where are all these food chains starting from? grasses, so now the grass is starting from a food web, what will we call it, it is the grazing food web, the second type of food web they are the detrital food webs, so detrital food webs are those food webs which start with the detritus or decaying materials, so detrital food web is a food web in which the food chains they are starting from the decaying material, that decaying material is starting from, now for example if we look at it, it is a decaying material, it is eating wood louse, it is eating birds, it can eat the predatory bird, so this will be a food chain, the second one is detritus, it is growing fungus on it, it is growing mushrooms, it is using humans, so this is the second food chain, this is detritus, it is growing mushrooms, it is eating different insects, insects are eating birds, so this is what we have, so this food web will be the base of which it is detritus, it is not green plants, this type of food webs they are called the detrital food webs, so detrital food webs are usually associated with decaying material, bacteria associated or fungus associated, so this is the diagram, this diagram basically represents both the things, this is a combination of grazing food web and detritus food web, so if you look at it, these are the grasses, these are grasses, one food chain is cow and the cow will be used as a human, the second food chain is the grass, the deer will be used as a human, the third food chain is the grass, it is using carnivores, the third one is the grass, it is using mouse, it is using birds, so it is using snakes on the grass, so the same different food chains are starting from the grass, so these are the food chains from the grass, this is called the grazing food web, now let's go to the other food web, that is the detrital food web, detrital food web starts with decaying material, it starts with detritus, if you look at it, the first one is detritus food web, it is eating earthworms, the bird is playing, this is a food chain, the second one is detritus, it is eating bugs, the bugs are not eating it, this is the second food chain, the third one is detritus, it is eating mushrooms, and the mushrooms are eating humans, so this is the third one, now these food chains that are starting from the detritus, they are also making a web, this web is called the detrital food web, so this is a detrital food web, now in the ecosystem, usually both the food web are side by side, the grasses and decaying material have the same food chains, and those food chains are with grasses, so this means that in the ecosystem, grazing and detrital food web, both of them are walking side by side, they are walking together, in the ecosystem, only grasses are present, grazing food web does not have detritus food web, because where the living material is, decaying will be there, and where decaying will be there, ultimately, detritus food web will be there, so if we look at the food web, the energy from the food web, the food chain, the food web basically represents how energy is travelling in the ecosystem, now the food chains are very complex, the easy method of studying the food chains is that instead of identifying every animal individually, it is better to design different levels of trophic, trophic levels, that is, different levels of food, so in the ecosystem, the food web, the food chains, the animals are designated at different trophic levels, like all plants, all the plants they will all present at the first trophic level, in the grazing food chain, the first trophic level will be of a plant, then the detritus food chain will be, third trophic level. So with this, it is easy to study the energy flow and the material flow in an individual animal. It is better to study the trophic levels in the ecosystem.