Habitats, part 4: Adding Isopods to the Terrarium

We have been observing our terrarium this past week for any changes. More than half of the grass has died out, due to overcrowding, we speculated (although I thought the fact that the terrarium had a few spills might have been a contributing factor.) We also noted that some other plants are making their appearance, as you can see in the lower right-hand corner of the photo above. We also looked evidence of our earthworms we added last week. The earthworms usually only come out at night, but they often leave clues to their movements, such as tunnels which can be seen on the side of the terrarium.

source

You can also find dirt formed into squiggle-like piles, which are really piles of castings, which are often used to hide the entrance to a tunnel. I couldn't get a photo of them, so I found one that looks like them to show you.

Isopods
This week we added some pill bugs, or more appropriately called Isopods, to our terrarium. (Isn't he cute?)

Quentin's sketches of a Isopod What we learned: Isopods have: source One pair of antennae (they actually have another smaller pair as well) Simple eyes Seven pairs of legs Seven separate segments they have antennae-like appendages out the back called uropods they are dark gray to light gray; sometimes they have a pattern are omnivores or scavengers feeding on dead or decaying plants or animals, but some may eat live plants they live under rocks or logs and similar places. This is because they breathe with gills. they are nocturnal. Some roll up into a ball when disturbed. We call them pill bugs because they look like pills when they roll up.

You might also want to see:

Habitats, part 1, Soil

Habitats, part 2, Building a Terrarium Habitat

Habitats, part 3, Adding Earthworms to the Terrarium

Habitats, part 3: Adding Earthworms to the Terrarium

Remember our terrarium we set up last week?

Look at it now!

We made journal entries using this method of drawing the plants, roots, and pebbles with crayon and giving it a watercolor wash afterwards.

This week we are adding earthworms.

 We have studied earthworms before as part of our nature study...

but a review never is a bad thing. The head is the pointed end.

If you have an earthworm in a clear plastic cup and hold it up to light, you can see the internal structures of the worm.

You can try to measure the length and diameter of the worm.

We are going to observe them this week and see if our terrarium changes due to their appearance.

Related Posts:

• One Small Square
• Worm Composting Project
• Nature Study 107: Earthworms

Sources:

• Plants in a Jar, Art Projects for Kids
• GEMS Guide, Terrarium Habitats

Links:

Habitats, part 2: Building a Terrarium Habitat

For the next few weeks we will be exploring a meadow habitat by creating a terrarium and adding to it, one at a time, easily obtained creatures. They will then observe the terrarium and see how the various animals interact to create a habitat. We will later add a second habitat, an aquatic habitat to which we will add aquatic animals and eventually making a self-supporting habitats column.

To begin, this week we are building the habitat and planting seeds.

What you will need:
3 empty and clear 2-liter bottles
aquarium gravel
rubber band
4-inch square piece of netting
soil
a couple dead leaves or small sticks

Step 1: Remove the labels off the 2-liter bottles. Cut the top off of the first bottle. Don't cut it too short, just chop off the spout so you have enough of a bowl left over so that we can later fill it with lots of water (when we begin the aquatic habitat portion.) 

Step 2:

Cut the top and the bottom off of the second clear bottle, making a clear coupler that will eventually link the two other sections together.

Step 3:

Cut the bottom off of the third clear bottle and save it. Now fill your top floor. Place the piece of netting over the neck of the bottle and secure it with the rubber band. With the bottle upside-down and the bottom off fill with about an inch of gravel then with a couple inches of soil and plant your choice of seeds (alfalfa, rye or mustard work well and are easily found in health food stores). Throw in a few dead leaves and a stick or two. Tape the bottom on to what is now the top of the terrarium. Don't tape it too tightly as we will be opening it up a few times to add more to our habitat.

Step 4:
Have your students sketch what you have done so far and make note of any observations throughout the week.




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Habitats, part 1: Soil (Nature Study, Lesson 216)

sources:
Cranberry Corner
Scribbit

Habitats, part 1: Soil (Nature Study, Lesson 216)

My boys, like most boys, play in dirt all the time, but they have never really taken a moment to look at it closely. I asked them to observe the color, texture of the soil in the backyard and to notice things such as roots, leaves, pebbles and any living critters. I asked them to divide their find into living and non-living things and also to think about how they relate to plants, animals and humans as a beginning to thinking about dirt as a part of ecosystems.

I had them sketch out a simple food chain We then talked about what each part of the food chain might possibly leave in the soil. Another great activity, which we didn't get a chance to do this time, is to encourage critters out of the soil with a lamp. Put a small amount of steel wool (not the kind with soap) in the bottom of a funnel to keep the soil from falling through the hole. Gently place 1-2 cups full of soil in the funnel. Place the funnel in a glass jar.  Place a desk lamp with an incandescent bulb above the funnel (about 8 inches from the soil) and watch as the tiny animals move downward through the soil to escape the light and heat and fall into the jar. If you are worried about the little guys escaping, you can put an inch or so of water in the bottom of the jar for them to fall into.

Comparing two types of soil brings even more observations and comparisons of color, texture, odor and moisture content. Clay soils tend to be sticky when wet and can easily be rolled into a ball. It absorbs and retains water. Sandy soils are crumbly and do not hold water well. We talked about places in which one soil would be desired over the other and why. 

We talked about how the different soils came to be. I also asked them to think about the fact that soil is a coating on all the earth. 

I made a "soil" parfait similar to the one at Almost Unschoolers.   As they ate their treat, I noted the different layers. 

The top layer, representing the organic material, is a mixture of nuts and chips on a layer of  top soil pudding. A gummy worm added to represent the living things in the layers of soil. The next layer down, the topsoil (pudding) is mixed with gravel (cookie crumbs). The next layer, the subsoil, is made up of some larger pieces of cookie to represent weathered rock and then at the very bottom, (cookie) bedrock.

We made a soil profile test of the soil in the backyard. To make a soil profile, fill a vial (we actually used an clean, empty spice bottle) with about one inch of dirt. 

Add a pinch or so of alum. This acts as a dispersing agent, helping the soil  particle to break into smaller part and settle out into layers by density. Fill to the top with water. Cover and shake vigorously and then let stand. The hard part is getting them not to touch it again at this point, to give it a chance to layer. While they are waiting, I asked them to make predictions of what they would see. 

Once it layered, we talked about what was in each layer and that some layers were larger than others. The floating layer is organic matter. The top layer is clay (usually mixed with the water), the middle layer is silt and the bottom layer is sand. It is fun to compare two sample to see the difference in the ratios. If you let the soil profile sit on a shelf for several days, the layers become even more pronounced.
You can compare two types of soil to compare and contrast the differences.

Ideas for further investigations: Handbook of Nature Study