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Biosphere
- Topics
- Scientific Method
- Alive
- Origins
- Water
- Biomes
- Food Webs
- Biodiversity
- Population Growth

Cells

Early Life

Invertebrates

Vertebrates

Humans

Plants

Food Webs

Introduction to this section:

Reading:
BBC News: Antarctic krill: Key food source moves south
BBC News: Killing rats could save coral reefs
Should tourists be banned from Antarctica?

Video 1: Food Webs (3:23)

Video 2: Food Chains Song (2:45)

Figure 1: Example of a food chain

Figure 2: Example of a food web

Study Guide (Transcripts/Summaries):
Organisms interact in an ecosystem in what are called food chains or food webs. The Sun provides the energy for these interactions and this energy flows through an ecosystem starting with the plants that are the primary producers that convert the light energy to chemical energy via photosynthesis. As animals eat plants and each other, some energy is lost as heat to the atmosphere. Each level in a food chain yields only 10% of the energy present in the previous level. Herbivores are primary consumers that eat plants. Predators and parasites are secondary consumers that feed on the herbivores. Scavengers and decomposers feed on dead plants and animals. Water, carbon and other building blocks of life cycle repeatedly through an ecosystem.

Sources:
Video 1: Food Webs, https://www.youtube.com/watch?v=o_RBHfjZsUQ
Video 2: Food Chains Song, https://www.youtube.com/watch?v=TE6wqG4nb3M
Figure 1: Food chain from: CK-12 Biology (say thanks), http://www.ck12.org/book/CK-12-Biology-Advanced-Concepts/, Figure 2.3
Figure 2: Food web from: CK-12 Biology (say thanks), http://www.ck12.org/book/CK-12-Biology-Advanced-Concepts/, Figure 6.7