Science: Lesson Two
Find out about DWoK! Student Page Language Arts Math Science Bibliography Science: Lesson Two


Ecosystems: Biotic and Abiotic Factors

Shawnda Zindler

Grade: Middle level, 7th grade

Student Centered Objectives:

Students will be able to:

Define and give examples of biotic and abiotic factors in an ecosystem.
Give examples of how living and non-living things interact within an ecosystem.
Explain and give examples of cultural perspectives of ecosystem interactions and stewardship of the land and it’s resources.
Use their senses to make and record observations in a natural setting.
Classify living and non-living things in an ecosystem.

Time required: 3-5 class periods


Pre-lesson bulletin board:

Crinkle Trees

(you will need two of these)

trees2.jpg (38922 bytes)
Cut a large piece of paper 1meter by 1 meter (approximately).
Along the top edge cut seven slits in the following lengths: 50cm, 35cm, 25cm, 10cm, 25cm, 35cm, and 50cm.
Crinkle each "branch" and the trunk and place on bulletin board or the wall in the shape of a tree for use later in the lesson. Label one-tree "Living" and the other "Non-Living"

Lesson one:

Instructor introduces the lesson by reading the story "Four Worlds: The Dine Story of Creation"

Discuss the meaning of the story, as understood by the students.

Discuss what "interactions" and "stewardship" mean.

Take students and their journals to the nearest tree. Have students use their senses to record what they see. Emphasize that they first record the "big" picture (whole tree, leaves, trunk, and ground) and then move into the smaller details (insects, bark, mosses, webs, twigs, rocks, and soils)

Proper journalizing includes sketches and labels describing each item.

Have students cut out four leaf shapes. On two of the leaves, students are to put two living things they observed on or around the tree and on the other two leaves they need to write two non-living things from their journalizing activity. Place a hook in each leaf (ornament hooks or paperclips work best) and hang on the proper trees on the bulletin board.

Lesson 2

Have students brainstorm what an ecosystem is. Discuss and share examples.

Introduce Abiotic (non-living things such as air, soil, water, temperature, and light) and Biotic factors (living things such as plants or animals) within an ecosystem. Use the student examples from the Crinkle trees. Have students add examples of factors that might be missing on the trees.

Have students rename the trees with the titles "Abiotic Factors" and "Biotic Factors".

To reinforce students understanding of one particular abiotic factor, soil, have students conduct the following observation activity.  BE SURE TO PREPARE THE MATERIALS ONE DAY PRIOR TO USE AS THE COLLECTION PROCESS IS TIME CONSUMING AND IT TAKES ABOUT 8 HOURS FOR THE SOIL TO PROPERLY SETTLE IN LAYERS IN THE JARS



Variety of soil samples (at least 8 small ziplock bags full and labeled as to where the soil came from)

8- quart size glass jars



In small groups, fill each jar with one sample of soil. Label the jar as to where the soil came from.
Fill the rest of the jar with water (stop about 10cm from the top).
Shake or stir the soil and water.
Let set overnight.
Without disturbing the soil, students measure each layer and write a description of what each layer looks like and the things contained in it (for example small pieces of twigs, leaves, rocks, etc.).
After students have recorded their observations of the jars; discuss as a class any relationship that might exist between the location of the soil (where it came from) and its composition.

Lesson 3: Interactions with in an ecosystem


Copy of story "Tunka-shila, Grandfather Rock"(Lakota{Sioux]- Great Plains)

Web Addresses for Lewis and Clark Journals and other famous journals.

Student Journals

Read aloud: "Tunka-shila, Grandfather Rock" (Lakota [Sioux]-Great Plains)

As a whole class, discuss interactions of Spirits with the Earth in this story and the natural creation of earth features because of these interactions.

Read the story: "The Buffalo Bull and the Cedar Trees" (Osage-Plains)

In small groups have the students reread the story and list and discuss what they believe are interactions within this story.

Share the groups’ findings with the whole class.

Have students research examples of famous journals on the internet. These could include but are not limited to Lewis and Clark, Divinci, etc. Have students copy one entry into their own journal as an example to follow.

Take a nature walk to a local park or on your own school grounds if there is a recreational use area there. In the students’ journals, have students record what they see as interactions in the area, again emphasize "big picture" to "small details" (this will help focus them)

Have students categorize their observations from the nature walk into biotic and abiotic factors.

Discuss interactions, interdependence. Look at park users (recreationalists, nature watchers, domestic animals, and park caretakers) and discuss their effects on this particular ecosystem and its components.

Lesson Wrap-Up:

Great Plains Buffalo

-Interdependence between Buffalo and Native Americans

Guest Speaker on the uses of the Buffalo.

Utilize the resources of a local museum (such as the People’s Center in Pablo, MT or the local culture committees of the various tribes. It is very important that students "see" actual items.

Have copies of the handout "Uses of the Buffalo" available for each student.

-At the end of the presentation, have students record three main points made by the guest speaker as well as a brief summary of their understanding of the interdependence between the Buffalo and Native Americans.


Student journals

Oral questioning


Student Journals (I usually have the students create their own) one per student

"Four Worlds: The Dine Story of Creation (Dine [Navajo] –Southwest)" from the book Keepers of the Earth, by Michael J. Caduto and Joseph Buchac, 1989.

"Tanka-shila, Grandfather Rock" (Lakota [Sioux]- Great Plains) from the book Keepers of the Earth, by Michael J. Caduto and Joseph Buchac, 1989.

"The Buffalo Bull and the Cedar Tree" (Osage-Plains) from the book Keepers of Life, by Michael J. Caduto and Joseph Bruchac, 1989.

Large Sheets of Butcher Paper (for Crinkle Trees)

Leaf shape cutouts (variety of colors and sizes)

Ornament hangers (or paper clips)

Soil samples, labeled

Several Quart-size glass jars


"Uses of the Buffalo" charts (one per student)


to the top of the page