Ecosystems
Topic 3: Food Chains and Webs
Part of the Local Ecosystems Module
Spotlight Biology Preliminary Text Chapter 4
Authors: D. Heffernan, J. Bastina, B. Grieve, K.
Humphreys, A. Sartor
Science Press 2002
Food Chains and Webs
In every ecosystem, plants
and animals are linked
together by feeding
relationships into food
chains and food webs.
medspa.saludenbalance.com
Food Chains and Webs
Looking at a few species at a time, we can imagine that a
primary producer, a herbivore and a carnivore all form a
simple food chain.
heightstechnology.edublogs.org
Food Chains and Webs
But if we observe all of the animals and plants in most
ecosystems, we see that relationships form large complex
networks called a food web in which many animals eat
several different kinds of food.
cabap.org
Food Chains and Webs
If we study a food
web or chain, we
must understand
that the arrow
shows the
direction along
which energy is
passed. In the
diagram we can see
the small animal
eats the arthropod.
soilfoodweb.ca
Food Chains and Webs
Furthermore, branches of most food webs interconnect with
those in adjacent areas. Food webs in ponds link up with those
of surrounding forests and feed into those of streams. The food
webs of coastal mangroves, estuaries and bays are also
interconnected.
healthcareworkforce.net
Activity
Students are to work in pairs to complete:
Box 4.1 Biology Skills: Food Chains and Webs Handout
Homework
With what do all food chains and webs start?
2. What do the arrows show in a food web or chain?
3. Construct a simple food chain for each of the following
environments
1.
1.
2.
3.
4.
Desert
Grasslands with only a few trees
Beach
Construct a food web for the open ocean