Definitions [5]
A food chain is the sequential sequence of living organisms in an ecosystem where one organism consumes another to transfer food energy.
A network of interconnected food chains showing how various organisms are related through feeding relationships is called a food web.
Define the following term and give two examples:
Symbiosis
It refers to relationships between organisms of different species that show on intimate association with each other. Symbiotic relationships provide atleast one of the participating species with a nutritional advantage.
Examples of Symbiosis Relationships are of Fungus and photosynthestic alga and Microbes and cattle.
Define the term predation.
A predator is any consumer that kills and eats another living organism in order to obtain energy. The organism being eaten is called the prey.
Define the food chain and give two examples.
Food chain, in ecology, the sequence of transfers of matter and energy in the form of food from organism to organism. Food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. Plants, which convert solar energy to food by photosynthesis, are the primary food source. In a predator chain, a plant-eating animal is eaten by a flesh-eating animal. In a parasite chain, a smaller organism consumes part of a larger host and may itself be parasitized by even smaller organisms. In a saprophytic chain, microorganisms live on dead organic matter.
Key Points
- A food chain is a linear sequence of living organisms in an ecosystem where food energy is transferred as one organism consumes another.
- The structural flow typically moves from primary producers to successive levels of consumers, such as from grass to insects, then to a thrush, and finally to a sparrow hawk.
- According to the principle of continuity, a complete food chain requires a continuous external energy supply, always beginning with photosynthesis and ending with decomposition.
- The principle of efficiency dictates that shorter food chains are more stable and energy-efficient because less energy is wasted across fewer transfers.
- Under the 10% law, only about 10% of the available energy is passed to the next trophic level, while the remainder is lost as heat through respiration.
- A food web is a complex network of interconnected food chains that illustrates the broader pattern of energy and nutrient flow within an ecosystem.
- The complexity of a food web increases with the length of its food chains and the availability of alternative dietary choices for consumers.
- Energy flow in an ecosystem is strictly unidirectional, meaning energy captured by autotrophs never reverts back to the solar input or to previous trophic levels.
- As energy transfers progressively through successive trophic levels, the total amount of available energy consistently diminishes due to energy loss at each stage.
- Biological magnification occurs when non-degradable, harmful chemicals enter the food chain and accumulate progressively at each consecutive trophic level.
- Because human beings occupy the apex or top level in food chains, the maximum concentration of these toxic chemicals ultimately accumulates within our bodies.
