energy flow - food chains/webs
TRANSCRIPT
Unit 4: Energy FlowObjective #1: Interrelationships and energy flow within a food chain and food web
Levels of Organization• The biosphere is where all life exists• Ecosystems include living (biotic) and
non-living (abiotic) factors
Levels of Organization• Populations consist of organisms of the
same species living in an area• Communities have several populations in
an area
Energy Flow
• Living things need energy• For growth, reproduction, metabolic
processes• No energy No life!• Where does energy come from?
Energy Flow: Producers
• The SUN provides energy• Producers make food
(autotrophic)• Plants and some bacteria
are photosynthetic• Some bacteria are
chemosynthetic
Energy Flow: Consumers• Heterotrophs rely on other organisms for
their energy • ie: herbivores, carnivores, omnivores,
scavengers, decomposers, and detritivores
Food Chains• Energy is transferred through an
ecosystem when organisms eat or are eaten
Trophic Levels • Feeding levels in a food chain or web• 1st Trophic Level – Producers• 2nd Trophic Level – 1st Order (Primary) Consumer…ETC
• Each consumer depends on the trophic level below it for energy!
Section 3-2
Figure 3-8 A Food Web
Food Web
• Many food chains together form a food web
Pyramid of Energy• 10% of the energy at one trophic level is
available to the organisms at the next level.
Biomass Pyramid• The amount of living tissue and
thus potential food• Typically the greatest biomass is
at the base
Pyramid of Numbers• Relative number of individual
organisms at each level• In certain ecosystems, it is NOT
pyramid shaped