Chapter 54 ECOSYSTEMS
Human impacts
Ecosystems
*Definition: all of the organisms that live in an area and their chemical/physical
environment.
*4 components linked by the flow of energy, fig 54.1:
Energy Flow in Ecosystems
o
Energy sources = trophic levels
, fig 54.7
o
Organisms that obtain energy from the same type of source occupy the
same trophic level.
o
Food chains
– connect different trophic levels and energy flows from the
producers upward.
o
Food webs
– most organisms eat more than one type of food and feed at
more than 1 trophic level, fig 54.8.
Food Web
o
Energy flow from 1 trophic level to the next is inefficient, declining as
much as 90% from 1 level to the next, fig 54.9
*Examples:
o
Food chains consist of no more than 3-4 trophic levels. Limits:
*Inefficiency of energy transfer (loss as heat energy)
*Stability of the environment
This
preview
has intentionally blurred sections.
Sign up to view the full version.

This is the end of the preview.
Sign up
to
access the rest of the document.
- Fall '09
- DINI
- trophic level, Greenhouse gas, Global Biogeochemical Cycles
-
Click to edit the document details