(c) McGraw Hill Ryerson 2007 Food Chains & Webs https://www.youtube.com/watch?v=0ZOvqYypOuo (c) McGraw Hill Ryerson 2007

An organism is a living thing. An organism: Energy Flow in Nature An organism is a living thing. Includes: Plants, animals, micro-organisms, fungi, insects An organism: Obtains energy from the environment Contributes energy to the environment Plants are called “producers” because they produce carbohydrates from carbon dioxide, water and the sun’s energy (in photosynthesis). E.g., flower “Consumers” get their energy by feeding on producers or other consumers. E.g., bee (feeds on flower) Decomposition (or biodegradation) is the break-down of wastes and dead organisms. It is done by organisms called “decomposers” or “detrivores.” E.g., bacteria, fungus, earthworm See pages 56 - 59

Examples of terrestrial and aquatic food chains Different methods are used to represent energy moving through ecosystems: Food chains Food webs Food pyramids (future class) Food chains show the flow of energy in an ecosystem Each step is a trophic level Producers = 1st trophic level Primary consumers = 2nd trophic level Secondary consumers = 3rd trophic level Tertiary consumers = 4th trophic level Top level = Top consumers or Top carnivores Examples of terrestrial and aquatic food chains See pages 59 - 60

Food Chains (continued) Consumers in a food chain can be classified as: Detrivores - consumers that obtain energy and nutrients from dead organisms and waste matter Includes small insects, earthworms, fungi Detrivores feed at every trophic level Detrivores have their own, separate food chains, and are very numerous This dung beetle is a detrivore. See page 61

Food Chains (continued) Detrivores Herbivores - primary consumers herbivores eat plants (producers) only Carnivores - secondary or tertiary consumers Secondary consumers eat herbivores Tertiary consumers eat secondary consumers Omnivores - consumers that eat both plants and animals Examples include humans and bears

Which is it: herbivore, carnivore or omnivore? Venus Fly Trap? http://www.discovery.com/tv-shows/life/videos/venus-flytrap-catches-flies/

Most organisms are part of many food chains. Food Webs Most organisms are part of many food chains. Food webs represent many interconnected food chains. Arrows represent the direction that energy flows. Following the arrows leads to the top carnivore(s). This food web represents a terrestrial ecosystem that could be found in British Columbia. See page 62

FOOD WEBS https://www.youtube.com/watch?v=MGODmyXkkPU (c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007 To Do Now Practice Package Read & Highlight Do the Questions (c) McGraw Hill Ryerson 2007