4.18 SUNLIGHT IN MY DINNER
All animal life ultimately depends on plants. Many plants, especially in food chains involving humans, grow on land and depend on the soil. Green plants capture solar energy to drive the synthesis of sugar from simple molecules like water and carbon-dioxide. They produce oxygen as a by-product of the reaction. But green plants depend on mineral elements they can get only from the soil. Thus, when soil is degraded or lost, land plant-based food chains are threatened. Ask students to write down a typical meal menu. For each item, try to work back to the sunlight trapped by green plants. Create as many food chains for different items as possible and set up a display using posters, charts, mobiles, or models to illustrate these chains.
4.19 LIFE IN THE SOIL
Take the students to an undisturbed section of forest or wood lot, after getting permission from the land owner. Spread out a plastic sheet. Mark off a square about .5 m on one side and have students use a hand trowel or small spade to remove the first 10 cm of the soil. Place the material on the plastic sheet, and have students spread the litter and examine it using hand lenses or magnifiers, taking note of the different life forms they find, and their numbers. Then set this material aside in a plastic bag or container. Have a second team of students then remove the next 10 cm of soil and repeat the procedure. Continue working, 10 cm at a time, until the last team reaches rock, clay, or gravel and there are no longer major signs of life in the soil. Each team should record its findings on a data form which they created. Return the samples in reverse order so the soil is restored.
On returning to class, put together a large poster or display illustrating the cross-sectional profile of the soil at the field site. Show the major life forms (plants and animals) and their locations in the profile. Do not forget to consider roots as part of a larger life form. Invite the class to consider the following:
- how deep was the actual soil in total;
- how many distinctly different layers were present and how did they differ;
- what was the base material below all the soil levels;
- how could the soil have been formed;
- what human actions might result in destructive changes to this type of soil profile;
- how could the soil be protected or conserved; and
- how could it be enhanced
[Sidebar:
Field activities enhance and expand upon isolated in-class activities, helping the student relate what is learned in the classroom to that of the physical world.]
4.20 BETTER FARMING THROUGH CHEMISTRY
At present, many gardeners and farmers use manufactured chemical fertilizers. Organic gardeners prefer to use natural fertilizers from manure, compost, or other organic processes. Have students work as a team to investigate both sides of the chemical versus organic fertilizer debate and report to the class concerning the two approaches and their advantages/disadvantages. Students should also consider biological versus pesticides as methods of weed control as well as the question of the make-up of the "ideal" lawn.
4.21 A CALL TO WORMS
Some Canadian cities now support household composting by making available composters at low cost and by providing information about worm composting for indoor use. Students can investigate whether or not their city has such a program and the reasons for or against. The class can set up a classroom worm composter. Many environmental groups and garden centres now carry kits for these composters or have information about how to establish one. The students should find out how worm composting works, and what advantages are claimed for it
LOSS OF NATURAL TERRESTRIAL HABITAT AND BIODIVERSITY
4.22 BIODIVERSITY AND GLOBAL CHANGE
This is an area where it may be very useful to assess students' prior knowledge of biodiversity before exploring the topic. One way of doing this is to have the students work in groups to develop large charts of the concept map variety, with the phrase "Biodiversity and Global Change" at the centre and connected concepts and ideas surrounding it. By sharing these charts students can see what ideas they have about biodiversity and its importance as an element of global change. This can lead to development of a study plan for the topic including areas where students clearly see a need for more information or where they identify debatable items.
[Sidebar:
This activity provides a good introduction to the concept of biodiversity.]
4.23 RAIN FORESTS, TROPICAL AND TEMPERATE
Why is it important to protect rain forests? Students could assemble maps and other graphics to represent both tropical rainforests and temperate rainforests (such as Canada's West Coast forests), and create displays or learning centres organised around headings such as:
- where are tropical rainforests to be found on the Earth at present?
- what is the problem-if tropical rainforests are threatened, why?
- why should Canadians care about tropical rainforests? After all, Canada does not have any tropical climate areas and no tropical rainforests?
- what can be done to save what remains?
One group of students could take responsibility for each topic and report to the class as a team. The teams can then assemble their findings into a common display or learning centre which might be set up in the school library.
This should be repeated for temperate rain forests. It could be expanded to included old growth forests in many regions of Canada. (See Appendix 1-Sample Lesson Plans for a detailed description of this activity.)
[Sidebar:
Emphasis should not be placed solely on tropical rainforests.]
4.24 TAKING STOCK?
Have students consult a map of their province to find out how much land is in various categories of use:
- national parks;
- provincial parks, where no use other than recreation in permitted;
- ecological reserves or protected wilderness areas where only limited access and use is allowed for any purpose;
- park lands where some consumptive uses such as cattle grazing or forestry are permitted;
- logging areas (tree farm permits or forest management areas) set aside for forestry;
- lands set aside for agricultural use; and
- urban lands
Focus the discussion on questions such as the following:
- What percentage of the province's land is in each category?
- What is the largest single block of wilderness habitat remaining in the province?
- What percentage of the province's land does this constitute?
- Does the province have a plan or program to acquire or protect wild lands, special habitats, wetlands, or endangered or threatened species?
- How much habitat has been protected or acquired through the program?
[Sidebar
Provincial departments of environment, Canada's State of the Environment, Statisitcs Canada Human Activity and the Environment and other provincial State of the Environment reports are likely candidates for this information.]
4.25 LAND USE POLICY
After gathering and discussing the information in Activity 4.24, the class should hold a meeting, electing a chairperson first, and decide if the province has an overall land use policy or strategy. The class might decide first what would be possible criteria for an effective provincial land policy; for example -Will the strategy:
- protect significant elements of the province's natural habitats so as to sustain them and protect their biodiversity?
- provide for protection of critical habitat for species which migrate through the province?
- provide for the protection of important agricultural lands?
- protect historical sites, riverside and stream banks (riparian habitats)?
- require sustainable forestry?
- encourage sustainable agricultural practices?
- address the land claims of First Nations peoples?
In putting together a critique and proposal of provincial land use policies the class may also wish to have teams of students interview or collect information from persons involved in conservation groups, First Nations, agriculture, tourism, forest industry, and real estate.
They could apply their criteria to a review of their findings about the provincial land legislation and policy and decide, in the class meeting, whether or not the province's current land use legislation or policy is adequate. The class could form a task force to develop "model policy" for the sustainable development of the provincial lands, using the criteria they have developed. A final step would be to invite a provincial official responsible for land policies to meet with the class to hear a presentation of their ideas and to outline the province's current land use programs.
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