Page 586E: Interactions of Life

Environmental Biology – Ecosystems
At this site by Marietta College you can find out more about energy flow through ecosystems, food chains and food webs, energy pyramids, and biogeochemical cycles in ecosystems.

Food Chains
Visit this site to learn all about food chains, trophic levels, and food webs. Scroll down to read about energy flow through food chains.

Food Chains and Food Webs – An Introduction
Go to this site to read a good introduction to energy flow through an ecosystem. Scroll down to read about decomposers.

Ecological Pyramids
Go to this site to read a brief introduction to the use of ecological pyramids to illustrate energy flow in food chains and food webs. Click on a pyramid of numbers to see graphics and explanations that illustrate the three types of ecological pyramids.

Fundamentals of Populations and Population Growth
Go to this site for definitions of ecosystems, populations, and population density. Scroll down to the bottom of the page and click on population computer models to see how mathematical and computer models can be used in the study and analysis of populations.

Population Index
Visit this site to find out more about the world’s human population. Go to the first sentence under the heading home and click on user’s guide to find out how to use this resource.

The Biosphere
Go to this site to see a description and definition of the term biosphere, and to find out how the biosphere is related to the atmosphere, hydrosphere, geosphere, and anthrosphere.

Frequently Asked Questions about Population Growth
At the site sponsored by the Union of Concerned Scientists you can find answers to frequently asked questions about world population growth. Click on how many people can the earth support to see what scientists have to say about this topic.

Carrying Capacity: How many coyotes can live in a woodlands?
Visit this Population Education site by the Iowa State University extension service for a science activity that demonstrates carrying capacity. Have your students work with a group of friends or classmates and find out how many coyotes a woodlands can support.

Exponential Growth
Visit this site for a graphic application of exponential growth in a fish population. Click on the run applet to see the interactive graphic, then click run to see how quickly the fish population grows. Your students can manipulate the graphic by following the directions at the site.