Food Webs and Abiotic Systems

RETURN TO INVERTEBRATE EXPLORATIONS

Earthworms belong to a separate group of invertebrates:  "The ringed Worms."

Food webs, roles in habitats: Producers, decomposers, herbivores, omnivores, predators, parasites

Part I: Decomposers

Engagement: Have students look through a decomposing pile of leaves, compost.  Find the creatures inside. Separate the living organisms and classify as possible. Look at the decomposing leaves and look for evidence that it is being eaten by-----------. 

Dead leaves have a great deal of nutrients that can be transferred to the soil, but they first must be broken down. Here are a list of creatures and organisms that can be found in a pile of rotting leaves below. A pdf is also available: LEAF LITTER BUGS.DOCX 

DECOMPOSERS: EAT DEAD OR DECAYING LEAVES OR COMPOST

Millipedes

Springtails are tiny white jumping insects.

Pill bugs and Sow bugs

PREDATORS (these eat the above creatures)

Ground Beetle

Centipede

Part II FOOD WEB

Who eats who? How does it all work?  The leaf pile is a microsystem where each organism has a role much like that on the plains of the Serengeti. There are lions and tigers and bears and their are antelopes, deer, wart hogs, and hyenas.  

Give students a diagram that shows one version of a food web:

Using a sheet of pictures of organisms above, have them arrange each with arrows to indicate interactions.

Part III: Engineering problem 1

 Students can explore the work of decomposers first hand by working with earthworms or soldier flies. Here is a simple method that can be done indoors

Students can create their own habitats and experiment with various food stuffs that are recycled from the cafeteria!

Here is an amazing industrial system:

Assessment

Giving students a challenge to create an earthworm habitat and then recycle food stuffs is a good candidate for an engineering study. Use the rubrics for engineering to guide assessment here.

Part III: Engineering problem 2

Animals and plants prefer certain habitats and niches based on food and environment, but much of the ability of a creature to thrive is dependent on abiotic conditions.  These include temperature, humidity, acid/base balance of soil or water, and amount of natural or artificial light.  Determining abiotic preferences requires designing experiments and apparatuses.  Here is an example of an apparatus to test invertebrate preferences of temperature.

Heat pack                                               Cold Pack

A tube made of overhead plastic is lined on the outside by a heavy piece of aluminum foil. On each end a source of heat or cold in placed. The aluminum foil transfers the heat or cold along the tube.  Thermometers read the temperature along the tube. Ideally the temperature would be 30 degrees centigrade to 15 degrees.  Bugs would be introduced in the center and then tracked to see where they want to rest.

How would students design something to determine humidity, light or substrate preference?

RETURN TO INVERTEBRATE EXPLORATIONS