Section 1.3: Energy Flows through Ecosystems

All living things need energy Where does all the energy come from for life on earth? THE SUN!

Feeding Relationships Autotrophs (Producers) Foundation of all ecosystems Ability to make their own food/energy

Feeding Relationships Heterotrophs Consumer – Must eat to obtain food/energy Carnivores – Eat only animals Omnivores – Eat both plants and animals Herbivores – Eat only plants Decomposers – Break down dead material Fungi Bacteria Earthworms

Energy Flow in an Ecosystem Energy Pyramid A model that shows the amount of energy available at each feeding level of an ecosystem Energy is lost as you move to top of the pyramid

Energy Flow in an Ecosystem Visually represented by a food web or food chain Autotrophs/Producers 1st level consumers (herbivores) 2nd level consumers 3rd level consumers 4th level consumers (top predators)

Food Web

Conclusion Questions What is the ONLY source of energy on earth? Why are plants important to an ecosystem? Does all the energy created by autotrophs travel up the ecosystem? Why? In a ecosystem, are there more autotrophs or top level consumers?

Video: http://studyjams. scholastic Video: http://studyjams.scholastic.com/studyjams/jams/science/ecosystems /food-chains.htm Video: http://studyjams.scholastic.com/studyjams/jams/science/ecosystems /food-webs.htm

Turn to slide of ecosystem community and explain that all of these creatures share the same habitat and are called a community. Tell students that together as a class, we are going to build food chains in this community (remind students that the energy in all living things originates from the sun, and that green plants are the only living organisms that can use energy from the sun to make food. Animals get energy by eating plants or other animals—opportunity here to introduce herbivore, carnivore, omnivore). Break students into four/five teams. Assign each team a different consumer around which they need to build a chain that always starts with the sun. Then have one representative from each team come up and draw their chain. Go through two rounds (assigning new consumers to fill in the gaps), then ask: What does this look like? [spider web…it is called a food web] Are there other food chains we can build that aren’t drawn on the board? What would happen if we removed [pick one species] from the food web? What if we removed two, three? What would happen? Hopefully students will come to understand the interdependencies of all living things in a habitat—and that if one is affected, they are all affected.