ECOLOGY - FOOD CHAIN AND WEB

An ecosystem is a community of living organisms interacting with the non-living components of the environment (air, water, mineral, soil). The living component is referred to as biotic component and the non-living component is the abiotic component. There is flow of energy through the ecosystem. The energy comes from the sunlight which is used in the process of photosynthesis. The energy trapped in the plants is transferred to other animals through feeding interactions. Once the plants and animal die, the energy is released back into the environment through the process of decomposition.

A population is defined as a group of organisms of the the same species, example, dog or cat population.

A community is a group of different population living within a specific area.

A biosphere  is the part of the earth where living organisms exist.

This is a link to more info on the ecosystem

FOOD CHAIN AND FOOD WEB

 A food chain is a simple linear diagram that shows organisms feeding and being fed upon by another organism.
 It looks like this: Organism 1 -----> Organism 2 ------> Organism 3 ------> Organism 4
This means that Organism 1 provides food for Organism 2, and Organism 3 provides food for Organism 4.

This is an example:



It is made up of producers and consumers. Decomposers such as bacteria are important in the food chain but they are not shown on the food chain.

Producers are the first in any food chain. They are the plants. They produce their food using the energy from the sun via photosynthesis.

Consumers can be classified as primary consumers, secondary consumers, tertiary consumers, and quartenary consumers, etc.

• primary consumers - They are the first to feed on the producers.
• secondary consumers - They feed on the primary consumers
•  tertiary consumers - They feed on the secondary consumers
• quartenary consumers -They feed on the tertiary consumers

Producers are also known as autotrophs because they can produce their own food.

Consumers are also known as heterotrophs because they cannot produce their own food.

Consumers can also be classified as herbivores, carnivores, or omnivores.

•  herbivore - Feeds on plants
• carnivore - Feeds on other animals
• omnivore - Feeds on both plants and animals

A food web is made up of a network of food chains. It is a more complex feeding relationship and interactions. This is an example of a food web.



Start with the producers (plants) and follow the arrows to show the feeding relationships. One organism can be a source of food for more than one organism. In the example above, grass provides food for rabbit which then is feed upon by the hawk. As you can see, the hawk also feeds on the field mouse and sparrow. You can come out with so many relationships in the above diagram.

As you study, think about the effect of  eliminating an organism from the food chain or web on the other organisms.