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The key points covered in this video include:

1. Food Chains
2. Food Webs
3. Trophic levels

Food Chains

Organisms live with and eat other organisms in a given habitat. One organism may eat plants and then itself get eaten by another organism - this establishes a food chain. A food chain is the sequence of feeding interactions between organisms in a given habitat. The food chain can be comprised of several different organisms: 1. The first organism is the producer - this is an organism that makes its own food by photosynthesis e.g. grass. 2. The second organism is the primary consumer - this is an organism that eats plants/ producers, and so is a herbivore e.g. rabbit. 3. The third organism is the secondary consumer - these are organisms that feed on primary consumers e.g. wild cat 4. The fourth organism is the tertiary consumer - these are organisms that feed on secondary consumers e.g. lions. 5. The final organisms are decomposers- these are microorganisms that break down organism remains e.g. fungi and bacteria.

Food Webs

However, no group of organisms in a food chain are isolated as one feeding chain can feed into a larger food web. A food web is a system of independet and interlocking food chains in a given habitat or larger ecosystem. When an organism is part of a larger, complex food web, a change in one component can affect the balance of the entire feeding system.

Trophic Levels

As we have seen, feeding relationships are sequenced into food chains. Each level or link in the food chain is known as a trophic level. A trophic level describes the position of an organism in a food chain or web and describes its feeding relationship with other organisms.

Summary

The feeding sequence in a given habitat is known as a food chain
A collection of interlocking food chains is called a food web
Each level in these chains is known as a trophic level
Different organism at different levels on the food chain and/or web have different names as consumers or as a producer
The decomposer is not usually mentioned on the food chain/web