Chapter 6 Ecosystems and Ecosystem Management

Basic Characteristics of Ecosystems Sustained life on Earth is a characteristic of ecosystems, not of individual organisms or populations Structure: –Living (Ecological Communities) –Non-living Processes –Cycling of chemical elements –Flow of energy Change (Succession)

Ecological Communities and Food Chains Ecological Communities are defined in 2 ways: –1. A set of interacting species that occur in the same place Food chains, food webs, trophic levels (autotrophs) –A set of species found in one area

Food Chains and Food Webs A Terrestrial Food Chain –4 trophic levels: Autotrophs Herbivores Carnivores Decomposers –People are omnivores An Oceanic Food Chain The Food Web of the Harp Seal

The Community Effect Species interact directly and indirectly Community-level interactions Keystone species –Have large effects on it’s community or ecosystem –Its removal changes the basic nature of the community Holistic View

How Do You Know When You Have Found an Ecosystem? Vary greatly in structural complexity. The watershed is a common, practical delineation. Common to all ecosystems is energy flow and cycling of chemical elements.

Ecosystem Management Ecosystem management is the key to conservation of life on Earth. If ecosystems cease to function we must supplement with our own actions. Must consider chemical cycling, energy flow, community-level interactions, and natural changes.