<–2/”>a >FOOD CHAIN- A food chain starts with producers and ends with top carnivores. The sequence of eaten and being eaten, produces transfer of food energy and it is known as food chain.
Grazing food chain-The consumers which start the food chain, utilising the plant or plant part as their food, constitute the grazing food chain.
This food chain begins from green Plants at the base and the primary consumer is herbivore
For example, In terestrial ecosystem, grass is eaten up by caterpillar, which is eaten by lizard and lizard is eaten by snake.
In AQUATIC ECOSYSTEM phytoplanktons (primary producers) is eaten by zoo planktons which is eaten by fishes and fishes are eaten by pelicans
Detritus food chain- The food chain starts from dead organic matter of decaying animals and plant bodies to the micro-organisms and then to detritus feeding organism called detrivores or decomposer and to other predators.
Litter —■Earthworms —■Chicken—■Hawk
Detritus food chain
The distinction between these two food chains is the Source Of Energy for the first level consumers.
- FOOD WEB
“A food web illustrates, all possible transfers of energy and nutrients among the organisms in an ecosystem, whereas a food chain traces only one pathway of the food”.
- ECOLOGICAL PYRAMIDS
The steps of trophic levels expressed in a diagrammatic way are referred as
ecological pyramids.
The food producer forms the base of the pyramid and the top carnivore forms the tip. Other consumer trophic levels are in between.
The pyramid consists of a number of horizontal bars depicting specific trophic levels which are arranged sequentially from primary producer level through herbivore, carnivore onwards. The length of each bar represents the total number of individuals at each trophic level in an ecosystem.
The ecological pyramids are of three categories-
1.Pyramid of numbers,
2.Pyramid of Biomass/”>Biomass, and
3.Pyramid of energy or productivity
- Pyramid of Numbers
This deals with the relationship between the numbers of primary producers and consumers of different levels. Depending upon the size and biomass, the pyramid of numbers may not always be upright, and may even be completely inverted.
(a) Pyramid of numbers – upright
In this pyramid, the number of individuals is decreased from lower level to higher trophic level.
This type of pyramid can be seen in Grassland ecosystem.
(b) Pyramid of numbers – inverted
In this pyramid, the number of individuals is increased from lower level to higher trophic level.
A count in a forest would have a small number of large producers, for e.g. few number of big trees. This is because the tree (primary producer) being
few in number and would represent the base of the pyramid and the dependent herbivores (Example – Birds) in the next higher trophic level and it is followed by parasites in the next trophic level. Hyper parasites being at higher trophic level represents higher in number.
A pyramid of numbers does not take into account the fact that the size of organisms being counted in each trophic level can vary
the pyramid of number does not completely define the trophic structure for an ecosystem.
- Pyramid of Biomass
In this approach individuals in each trophic level are weighed instead of being counted. This gives us a pyramid of biomass, i.e., the total dry weight of all organisms at each trophic level at a particular time.
Biomass is measured in g/m2.
(a) Upward -pyramid For most Ecosystems on land, the pyramid of biomass has a large base of primary producers with a smaller trophic level perched on top
(b) Inverted pyramid-In contrast, in many aquatic ecosystems, the pyramid of biomass may assume an inverted form
- Pyramid of Energy
To compare the functional roles of the trophic levels in an ecosystem, an energy pyramid is most suitable.
An energy pyramid, reflects the laws of Thermodynamics, with conversion of Solar Energy to chemical energy and heat energy at each trophic level and with loss of energy being depicted at each transfer to another trophic level.
Hence the pyramid is always upward, with a large energy base at the bottom.,
A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another. Food chains are a basic way of understanding an ecosystem and the transfer of energy within it.
A food web is a more complex diagram that shows the feeding relationships between all the organisms in an ecosystem. Food webs are more realistic than food chains because they show that most organisms eat more than one type of food and are eaten by more than one type of predator.
A trophic level is a position in a food chain or food web. The first trophic level is occupied by producers, which are organisms that can make their own food using sunlight or chemicals. The second trophic level is occupied by consumers, which are organisms that eat other organisms. Consumers can be herbivores, which eat plants, carnivores, which eat animals, or omnivores, which eat both plants and animals. The third trophic level is occupied by decomposers, which break down dead organisms and return nutrients to the Soil.
A producer is an organism that can make its own food using sunlight or chemicals. Producers are the first trophic level in a food chain or food web. Examples of producers include plants, algae, and bacteria.
A consumer is an organism that eats other organisms. Consumers are the second trophic level in a food chain or food web. Examples of consumers include animals, Fungi, and protists.
A decomposer is an organism that breaks down dead organisms and returns nutrients to the soil. Decomposers are the third trophic level in a food chain or food web. Examples of decomposers include bacteria, fungi, and earthworms.
Detritus is dead organic matter. Detritus is a source of food for decomposers.
Energy flow is the movement of energy through an ecosystem. Energy enters an ecosystem through Photosynthesis. Photosynthesis is the process by which plants use sunlight to make food. Energy is then transferred from producers to consumers to decomposers.
Nutrient cycling is the movement of nutrients through an ecosystem. Nutrients are essential for life. They are recycled through the ecosystem by producers, consumers, and decomposers.
Ecological efficiency is the Percentage of energy that is transferred from one trophic level to the next. Ecological efficiency is usually low, meaning that most of the energy is lost as heat.
Biomagnification is the increase in concentration of a substance in an organism as it moves up a food chain. Biomagnification can occur with pollutants, such as DDT.
Food web complexity is the number of different trophic levels and the number of different species at each trophic level in a food web. Food web complexity can vary from ecosystem to ecosystem.
A keystone species is a species that has a large impact on an ecosystem, even though it may make up a small part of the ecosystem. Keystone species can be either predators or prey.
Mutualism is a relationship between two species in which both species benefit. Examples of mutualism include pollination and seed dispersal.
Commensalism is a relationship between two species in which one species benefits and the other species is not harmed. Examples of commensalism include barnacles living on whales and epiphytes growing on trees.
Parasitism is a relationship between two species in which one species, the parasite, benefits and the other species, the host, is harmed. Examples of parasitism include tapeworms and fleas.
Competition is a relationship between two or more species that are trying to obtain the same Resources. Competition can be for food, water, shelter, or mates.
Predation is a relationship between two species in which one species, the predator, kills and eats the other species, the prey. Examples of predation include lions eating zebras and wolves eating deer.
Herbivory is a type of predation in which an animal eats plants. Examples of herbivores include cows, rabbits, and deer.
Carnivory is a type of predation in which an animal eats other animals. Examples of carnivores include lions, tigers, and wolves.
Omnivory is a type of predation in which an animal eats both plants and animals. Examples of omnivores include humans, bears, and pigs.
Scavenging is a type of predation in which an animal eats an animal that has already died. Examples of scavengers include vultures, hyenas, and crows.
Detritivore is a type of consumer that eats detritus. Examples of detritivores include earthworms, bacteria, and fungi.
1. What is a food chain?
A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another.
2. What is a food web?
A food web is a Network of interconnected food chains.
3. What are the different types of food chains?
There are three main types of food chains: grazing food chains, detrital food chains, and parasitic food chains.
4. What are the different types of food webs?
There are two main types of food webs: terrestrial food webs and aquatic food webs.
5. What are the different levels of a food chain?
The different levels of a food chain are the producers, consumers, and decomposers.
6. What are the different types of producers?
The different types of producers are plants, algae, and photosynthetic bacteria.
7. What are the different types of consumers?
The different types of consumers are herbivores, carnivores, omnivores, and detritivores.
8. What are the different types of decomposers?
The different types of decomposers are bacteria, fungi, and protists.
9. What is the role of producers in a food chain?
The role of producers in a food chain is to convert sunlight into energy that can be used by other organisms.
10. What is the role of consumers in a food chain?
The role of consumers in a food chain is to eat producers or other consumers.
11. What is the role of decomposers in a food chain?
The role of decomposers in a food chain is to break down dead organisms and return nutrients to the soil.
12. What is the importance of food chains and food webs?
Food chains and food webs are important because they provide a way for energy to flow through an ecosystem. They also help to regulate the populations of different species.
13. What are some examples of food chains?
Some examples of food chains include:
- Grass grasshopper frog snake hawk
- Plant insect bird hawk
- Phytoplankton Zooplankton fish larger fish shark
14. What are some examples of food webs?
Some examples of food webs include:
- A forest food web
- An aquatic food web
- A desert food web
15. What are some threats to food chains and food webs?
Some threats to food chains and food webs include:
- Habitat loss
- Pollution
- Overpopulation
- Climate change
16. What are some ways to protect food chains and food webs?
Some ways to protect food chains and food webs include:
- Conserving habitats
- Reducing pollution
- Managing populations
- Mitigating Climate Change
17. What are some benefits of protecting food chains and food webs?
Some benefits of protecting food chains and food webs include:
- Maintaining Biodiversity-2/”>Biodiversity
- Regulating the climate
- Providing food and water
- Protecting human Health
Question 1
Which of the following is not a type of food chain?
(A) Grazing food chain
(B) Detritus food chain
(C) Parasitic food chain
(D) Predator-prey food chain
Answer
(D)
A predator-prey food chain is a type of food web, not a food chain.
Question 2
In a grazing food chain, the primary producers are:
(A) Plants
(B) Animals
(C) Fungi
(D) Bacteria
Answer
(A)
Plants are the primary producers in a grazing food chain. They are the organisms that use sunlight to create food through photosynthesis.
Question 3
In a detritus food chain, the primary consumers are:
(A) Decomposers
(B) Scavengers
(C) Herbivores
(D) Carnivores
Answer
(A)
Decomposers are the primary consumers in a detritus food chain. They are the organisms that break down dead organisms and organic matter into simpler substances.
Question 4
In a parasitic food chain, the parasite is:
(A) The organism that benefits from the relationship
(B) The organism that is harmed by the relationship
(C) Both the organism that benefits and the organism that is harmed by the relationship
(D) Neither the organism that benefits nor the organism that is harmed by the relationship
Answer
(A)
In a parasitic food chain, the parasite is the organism that benefits from the relationship. The parasite lives on or in another organism, called the host, and obtains nutrients from the host without providing anything in return.
Question 5
In a food web, the arrows represent:
(A) The flow of energy
(B) The flow of nutrients
(C) The flow of information
(D) The flow of genes
Answer
(A)
In a food web, the arrows represent the flow of energy. Energy flows from the sun to the primary producers, then to the primary consumers, then to the secondary consumers, and so on.
Question 6
A food web is a network of interconnected food chains. This means that:
(A) Each organism in a food web is part of only one food chain
(B) Each organism in a food web is part of multiple food chains
(C) There is no such thing as a food web
(D) Food webs are not real
Answer
(B)
Each organism in a food web is part of multiple food chains. This is because organisms can eat more than one type of food, and they can be eaten by more than one type of predator.
Question 7
Food webs are important because they:
(A) Help to regulate the populations of organisms
(B) Provide a source of food for organisms
(C) Help to maintain the balance of nature
(D) All of the above
Answer
(D)
Food webs are important because they help to regulate the populations of organisms, provide a source of food for organisms, and help to maintain the balance of nature.