Rock Flip

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What We're Doing

In this activity, you will sample the soil critter population at your field site by flipping over a board or rock and counting the different types of critters you find.

Why We're Doing It

Diversity is very important in natural ecosystems. Healthy soil tends to have lots of different kinds of organisms living in it. Using sampling techniques to monitor the population and biodiversity of an area is effective over a long period of time. When scientists collect this data for 10 or more years, they can establish a "baseline of health" which tells them the normal population size for that specific area. Major declines or increases in population size over a short amount of time can be a sign that human activity is affecting the population.

Making the connection:

• By doing this activity along with the Soil Temperature Test, Compaction Test, Percolation Test, Texture Test, and Mud Shake, you can learn how the physical properties of soil affect the critters that live there.
• By doing this activity along with Air Temperature and Cloud Cover, you can learn how these environmental factors affect the creatures living underground.
• By doing this activity along with Looking for Life, you can compare the numbers and varieties of critters you find in different micro-habitats.

Getting Our Hands Dirty

Hypothesize

What types and numbers of soil critters can you find under a rock or board at your field site?

Plan it!

• If you haven't already done so, choose a field site and map it in your field journal.
• At least a week before you do this activity for the first time, place your board out on a grassy area so that it lays flat on the ground. If possible, the board should be hidden under leaf litter, grass clippings, etc. If you plan to collect this data over a period of time, be sure to place your board where it will not be disturbed or disturb others. If this is not possible, look for large rocks already in your field site that you can turn over instead.
• Decide how often to check your board or rock. If you are working with a group or as a class, you should decide together. As you decide, think about these questions:
  • How might your results be affected if you collect this data daily?
  • How might your results be affected if you collect this data monthly?
  • How might your results be affected if you collect this data annually?
• Before you get started, review the Underground Adventure Field Guide to become familiar with the organisms listed there. Print out a copy of the Underground Adventure Field Guide to take with you into the field. You can also prepare by doing the Critter Quiz online activity.

Do it!

1. Flip over the board or rock.
2. Count the number of each different type of critter you find under the board or rock. You should work quickly to count the critters before they run away.

Record it!

• Record the types and number of critters you find on the Rock Flip worksheet . If you are working with a group, have one person record the data while others count. If you are not sure what a critter is, draw it or record a description of the critter.
• After you have counted and recorded the organisms you found, look up any unidentified organisms in the Underground Adventure Field Guide . Record this identification on the data sheet.
• Add the worksheet to your field journal.

Remember, be sci-wise!

• If you are able to collect data from beneath your rock or board over a period of time, remember to collect the data at the same time of day each time and to collect it on a regular basis.
• Treat the critters you find with respect. Do not handle them unnecessarily.

Thinking About It

• Did you find the creatures you expected to find under the rock or board? Were there more critters than you expected to find? Fewer?
• Based on the data you collected, do you think your hypothesis was correct or incorrect? Why?
• How did the types and numbers of creatures you found here differ from the creatures you found in the soil sample in Looking for Life? What might cause those differences?
• How did the critters react when you moved the board or rock? Did they move quickly or slowly? Why might they have reacted like this?
• What effect does moisture have on the types and numbers of creatures in the soil?
• What patterns or links did you notice between the creatures found in the soil and the air temperature? Did the air temperature have more or less of an effect on the critters you saw in this study than they had on the critters you saw in Looking for Life?
• If you were to continue collecting this data for a whole year, what differences would you expect to find? What differences would you expect to find if you collected this data over 10 years?
• Fill in this section of the Soil Biodiversity Overview worksheet .
• Looking at the bigger picture, how might the data you collected here help you to answer your research question?

Still Interested?

If you liked this activity, try these:

• Bug Moves
  You probably observed the soil critters moving quickly when you flipped the board or rock. Try drawing a bug and animating its movements based on what they observed. You can do this by creating a flip book or using a computer animation program.
• Bug Art
  Create a piece of music, a dance or a piece of art inspired by the activity you observed when you flipped the board or rock. The art doesn't need to depict the critters you found, but should give the same sense of movement.

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