Food Webs. Energy Flow in Ecosystems

Page
1

Slide 1

Energy in Ecosystems

Food Chains, Food Webs and Energy Pyramids

Slide 2

Producers (Autotrophs)

Photosynthetic organisms

Capture energy from sunlight, CO2 and H2O

Most producers are photosynthetic

Chemosynthetic organisms

Capture energy from chemical compounds in the surroundings

Slide 3

Consumers (Heterotrophs)

Herbivores

Eat only plants and fungi

Omnivores

Eat both plants/fungi and animals

Carnivores

Eat only animals

Detrivores

Eat dead organic matter

Decomposers

Break down organic matter into simpler compounds

Slide 4

Movement of Energy

Trophic Structures

Manner in which energy moves through an ecosystem

Each ecosystem has its own unique trophic structure

Slide 5

Biotic Energy Movement

Producers

Autotrophs (Photosynthesizers, Chemosynthetic organisms)

Primary consumers

Herbivores and omnivores that eat producers

Secondary consumers

Carnivores and omnivores that eat herbivores

Tertiary consumers

Carnivore eats another carnivore

Decomposers and Detrivores

Consume decaying producers and consumers

Slide 6

Food Chain

Energy is lost in each step up a food chain

Only 10 percent of the energy from one level on the food chain is available to the next level

Slide 7

Food Webs

Many consumers and decomposers have more than one food source

Movement of energy occurs in complex webs rather than in simple chains

Slide 8

Arctic Marine Food Web

Slide 9

A Simplified Food Web?

Slide 10

Slide 11

Energy Pyramids

Energy pyramids show the reduction of available energy at each higher trophic level

Slide 12

Biomass Distribution

Slide 13

Why a Pyramid?