Energy in Ecosystems

Read Page 32 – 33

Answering the following questions: What is the source of all energy on planet Earth? What is photosynthesis? What percentage of the Sun’s energy is used by photosynthesis?

Read pg. 34-39

Definitions Primary consumer Trophic level Secondary consumer Tertiary consumer Food chain Food web Biodiversity Top carnivore Trophic level Producers/ autotrophs Consumers/Heterotrophs Textbook Questions on page 39 Questions: 1-7, 9-10, 14

The Sun Source of energy for (almost) all ecosystems

Trophic Levels Each step in a food chain Means “feeder level” (from Greek etymology)

Producer/autotroph Organisms that produce their own food (energy) Means “self feeders” First trophic level

What is your favourite food? Why do we eat food?

Consumer / Heterotroph Organisms that eat other organisms to obtain energy

Primary consumers Second trophic level Producers are their source of energy AKA herbivores

Secondary Consumers Third trophic level Primary Consumers are their source of energy AKA Carnivores

Tertiary Consumers Fourth trophic level Secondary consumers are their source of energy AKA Carnivores

Detrivores/ Decomposers Detritus (dead organic matter) is their source of energy Feed at every trophic level Very important for nutrient cycling in ecosystems

Food Chain vs Web

Food Chain a one way flow of energy showing whom eats whom in an ecosystem.

Food Web Shows a feeding relationship between organisms in an ecosystem (often multiple connections per organism, i.e. multiple food chains) More accurate – what would happen if you only ate one type of food???

Biodiversity The variety of different types of species found within an ecosystem

Top Carnivore A consumer who has no predators Found at the top of food webs

Students are to label with autotroph or heterotroph Producer or consumer Primary consumer Secondary consumer Tertiary consumer Quaternary consumer Herbivore, carnivore, top carnivore How many trophic levels are there? Which trophic level does the plants occupy? Which trophic level does the owl occupy?

Some more definitions  Herbivores – “plant eaters” Carnivores – “meat eaters” Omnivores – eats both plants and animals Detrivores – feed on detritus (dead organic matter) and poop. Feed at every trophic level.

What is your favorite animal? Illustrate a food chain to include your favourite animal! Must have at least four trophic levels!