Energy Flow - Food Chains/Webs

1. Unit 4:
Energy Flow
Objective #1: Interrelationships and energy
flow within a food chain and food web

2. Levels of Organization
•The biosphere is where all life exists
•Ecosystems include living (biotic) and
non-living (abiotic) factors

3. Levels of Organization
•Populations consist of organisms of the
same species living in an area
•Communities have several populations in
an area

6. Energy Flow
•Living things need energy
•For growth, reproduction, metabolic
processes
•No energy  No life!
•Where does energy come from?

7. Energy Flow: Producers
•The SUN provides energy
•Producers make food
(autotrophic)
•Plants and some bacteria
are photosynthetic
•Some bacteria are
chemosynthetic

8. Energy Flow: Consumers
•Heterotrophs rely on other organisms for
their energy
•ie: herbivores, carnivores, omnivores,
scavengers, decomposers, and detritivores

9. Food Chains
•Energy is transferred through an
ecosystem when organisms eat or are eaten

10. Trophic Levels
•Feeding levels in a food chain or web
•1
st
Trophic Level – Producers
•2
nd
Trophic Level – 1
st
Order (Primary) Consumer…ETC
•Each consumer depends on the trophic level
below it for energy!

11. Section 3-2
Figure 3-8 A Food Web
Food Web
•Many food chains
together form a
food web

12. Pyramid of Energy
•10% of the energy at one trophic level is
available to the organisms at the next level.

13. Biomass Pyramid
•The amount of living tissue and
thus potential food
•Typically the greatest biomass is
at the base

14. Pyramid of Numbers
•Relative number of individual
organisms at each level
•In certain ecosystems, it is NOT
pyramid shaped