Ecology and Ecosystems: Food Chains, Webs, and Energy Flow

What is Ecology?

The study of relationships between organisms and their environment.

What does the prefix 'Eco-' refer to?

Habitat or environment.

What is an Ecosystem?

A community of living things along with their natural environment, including interactions of biotic and abiotic components.

What are biotic components?

All the living organisms that inhabit the environment, including predators, food sources, and competitors.

What are abiotic components?

Nonliving elements in an ecosystem such as temperature, moisture, air, salinity, and pH.

How does energy move through an ecosystem?

Through food chains and food webs.

What are trophic levels?

The feeding positions in a food chain or web.

How do humans fit into trophic levels?

Humans are primary consumers when eating plants, secondary consumers when eating cows, and tertiary consumers when eating salmon.

What is a Food Web?

Multiple pathways through which energy and matter flow through an ecosystem, including many intersecting food chains.

What is an Energy Pyramid?

A representation of a food chain that shows how food energy decreases as you move up the food chain.

What is the 10% law in ecology?

Only about 10% of the energy taken in by an organism is available to the organisms at the next trophic level.

What happens to energy as it moves up the food chain?

Energy decreases due to loss through life processes and heat.

What is the Pyramid of Numbers?

A representation that shows how the number of organisms decreases as you move up the pyramid.

If there are 15,000 calories at the producer level, how much energy is available for primary consumers?

1,500 calories (10% of 15,000).

If there are 15,000 calories at the producer level, how much energy is available for secondary consumers?

150 calories (10% of 1,500).

If there are 15,000 calories at the producer level, how much energy is available for tertiary consumers?

15 calories (10% of 150).

Why are there fewer animals at the top of the energy pyramid?

Due to energy loss at each trophic level, there is less energy available to support higher trophic levels.