CATALYST 5 minutes Producer: ______________ Consumer: _____________ Write down 2 specific examples of an organism that is a: Producer: ______________ Consumer: _____________ Decomposer: ___________

In a food chain, nutrients and energy flow move from producers to consumers to decomposers.

A simple example is: berries  mice  black bear Arrows show which way energy flows. (They point to the EATER.)

Most food chains consist of two, three, or four transfers of energy.

At each level, a certain amount of energy is also transferred to the environment as heat.

Each organism in a food chain represents a feeding step, or trophic level, in the passage of energy and materials.

Many species may occupy each trophic level in an ecosystem, so a food web is a better model because it shows all the possible feeding relationships at each tropic level in a community.

Organisms depend on more than one other species for food.

Food Webs

What will happen to the snake population if the mouse population increases? What will happen to the rabbit population if the mouse population increases?

Draw or write one food chain within this web.

What relationship do the scorpion and grasshopper in the web have?

Name one role the roadrunner would have in this web.

How would the lizard be affected by a decrease in the grasshopper population?

Which population in this food web would most likely be negatively affected by an increase in the mouse population? (1) snake (2) rabbit (3) wolf (4) hawk

OUT Gardeners sometimes use slug traps to capture and kill slugs. These traps were tested in a garden with a large slug population. Organisms found in the trap after one week are shown in the table below. - How many organisms in the trap were herbivores? - How many were carnivores? - How many were omnivores?