Lesson 6 - The Rain Forest, The Raptor Center at the University of Minnesota

©The Raptor Center

State Goals for Environmental Education (as per the Minnesota State Plan for Environmental Education, Greenprint, 1993)

Students will:

1. Provide experiences to increase their sensitivity and stewardship for the environment.
2. Understand the cause and effect relationship between humans attitudes and behavior and the enviroment.
3. Understand ecological systems.

Students will:

1. Understand the basics of the tropical rain forest ecosystem.
2. Be able to list the four general layers of vegetation found in the tropical rain forest.
3. Describe the basic interactions between plant levels of the tropical rain forest Ecocolumn.

• rain forest
• ecology
• tropical
• migration
• satellite
• telemetry
• equator
• canopy
• sun seekers
• under story
• forest floor
• crowns
• epiphytes
• parasites
• photosynthetic
• decompose
• leaf litter

• 1 Bottle Biology Tool Kit per student or work group
• various house plants (See Activity Section)

Each fall the ospreys in Minnesota begin their journey south to the rain forest regions of southern Central America and northern South America. Indeed, this is the southern terminus of the "Highway to the Tropics!" If Minnesotans are to understand the complexity of wildlife ecology, we must educate ourselves about all the pieces to the intricate global puzzle. Some wildlife issues are within the borders of our state and others stretch to far places, such as the rain forest. This lesson plan will familiarize students with a piece of the puzzle as it relates to osprey ecology.

Observers from the tropical regions report that most ospreys reach their winter quarters by late November and remain there, showing only local movement, until return migration begins in late February. Studies are under way at The Raptor Center-University of Minnesota and elsewhere to determine the migration and wintering routines of Minnesota ospreys as well as a small sample of birds from the Pacific and Atlantic Coast populations. Bird banding studies of ospreys have concluded that most US ospreys winter in Central and South America, and European ospreys winter in similar latitudes in Africa.

In general, US ospreys are divided into three "groups." The Atlantic, Midwest, and Pacific populations. Each population winters in somewhat distinct areas in the tropics. There is overlap and exceptions in the geographical distribution of US ospreys. Generally, the Atlantic population winters in the northeast and north central areas of Central and South America and the Pacific populations winter in the northwestern and western portions of Central and South America. The Midwestern population seems to winter in the same areas as the Pacific population. The new satellite telemetry studies at The Raptor Center and elsewhere will assist in defining these patterns.

Rain forests are a type of tropical forest, other types include: humid seasonal forests, savanna forests, and semi-arid thorn forests. Rain forests and humid seasonal forests are often referred to together as the tropical moist forests. The rain forest typically receives at least 49 inches of rain a year and sometimes as much as 312 inches per year! The average temperature in the rain forests is 81 degrees F. The tremendous lushness of these forests is due to the constant temperature and rainfall year-round. Because there is no dramatic seasonal changes, plants thrive all year long.

The thin band of rain forest that parallels the equator--in the Americas, Asia, and Africa---covers just 6 % of the earth's surface and contains half the worlds species! These fertile regions throughout the world are slowly being destroyed at an alarming rate. The rate of bird and mammal extinctions in the world has increased fourfold from 1600 to 1950. Many have occurred in the rainforest region.

As we take great pride in our Minnesota wildlife and landscape we must also recognize the need to help other countries protect their forested regions that provide winter homes for some of "our" animals

1. Create an Tropical Ecocolumn**

Click here to see a Tropical Ecocolumn

(**This activity is utilized with the permission of University of Wisconsin-Madison, Department of Plant Pathology-Fast Plants, 1630 Linden Dr. , Madison, Wisconsin 53706. It is from the Bottle Biology Project which was funded from the National Science Foundation from 1989-1993, the book Bottle Biology is available at local bookstores. Many other projects are in this book.)

Plastic beverage bottles provide the primary material for this activity. They are readily available - millions are produced and discarded daily and are easy to cut and combine in a wide variety of ways for science projects. These basic instructions are meant to get you started, showing how plastic bottles can be taken apart, cut, and connected. Once these basic techniques are mastered, you can follow the directions to make a tropical ecocolumn.

Removing the Label and Base.
Both the bottle label and base may be readily removed. The label and base are held in place with a heat-sensitive glue. To remove them, the glue must be softened with heat.

Follow these instructions:

• A) Fill the bottle about 1/4 full with very hot (120 - 150 degrees F) water. If the water is too hot (170 - 212 degrees F) the plastic will soften, warp, and may permanently crumple. Screw the cap back on firmly. This will retain pressure inside the bottle allowing you to hold the bottle tightly without crushing or denting it.
• B) Tip the bottle on its side so the water warms the area where the label is attached to the bottle - this will soften the glue. Catch a corner of the label with your fingernail and gently peel it from the bottle. If there is resistance, you may need hotter water.
• C) To remove the base, tip the bottle upright so the hot water warms the glue holding the bottle bottom to the base. Hold the bottle tightly and slowly twist off the base.
• D) Remove the cap and pour the water out slowly. You might try swirling the bottle around as it begins to empty, causing the water to form a vortex resembling a tornado funnel. This lets the water to swirl slowly out of the bottle mouth without buckling the sides.
• E) Usually most of the glue from the label and base is left on the bottle. It can be removed by scraping with a sharp-edged piece of metal or plastic while the glue is still warm. It can also be chemically softened and removed with a solvent such as cleaning fluid. Put a small amount on a paper towel and rub. This works best if most of the glue has been removed by scraping. Be sure there is adequate ventilation.
• F) Save all parts - bottle, cap, and base. You may need them later.

Cutting Techniques. Plastic bottles can be cut and modified in a great variety of ways but before you begin cutting, plan carefully. Remember that some bottles are wider than others, some have larger bases, and some have more tapered shoulders. The bottle shape and location of the cuts affect how your pieces fit together.

1. Place bottles on their sides in an empty drawer, tray, or box. Shallow cardboard flats and computer paper box tops work well. Hold the bottle up against the side and corner of the box to stabilize it while rotating. Brace a felt-tip pen against the box with the tip just touching the bottle and roll the bottle slowly around. This will leave an even line encircling the bottle. Sometimes it's easier to do this cooperatively. One person holds the bottle and rotates, while the other keeps the pen tip touching the bottle.
2. Use a single-sided razor blade or utility knife to begin the cut, slicing along the cutting line about two inches. Insert the tip of the scissors and snip your way around the rest of the cutting line. Because the scissor blades tend to catch in the plastic, it may be easier to snip along with just the tips. Trim away rough edges and irregularities with the scissors. Once the bottle is cut open, you can snip more from the shoulder, hip or side if you decide shorter lengths are needed. When in doubt about how pieces may fit, cut them a little too long - you can always re-move the extra length. Because it is more difficult to draw lines once a bottle has been cut, draw all intended lines before cutting.

Joining Bottles. Tape is the best material for joining bottles and will help columns survive handling in the classroom. However, not all tape is created equal! Postal tapes that are clear, waterproof, and wide (about 5cm), work well. For a large number of constructions, buy a dispenser. The best tape, and most expensive, is bookbinding tape.

Some construction requires waterproof joints. Since even a waterproof tape will eventually leak, we recommend using silicone sealant.

A few tricks when using silicone:

• Silicone cures over a 24-hour period and is slippery when fresh. Fix the joint to be sealed with small pieces of tape, which you can remove after the seal has solidified.
• Buy your sealant in a tube with a nozzle that you can fit as far into the joint as possible. This will give you a strong and waterproof seal.
• Keep the silicone bead thin, 2mm in diameter, so it sets in 24-hours.
• The chemicals used in silicone sealant are a health hazard. Use silicone only in a well-ventilated area.

Now lets take a look at the Tropical Forest Ecocolumn. Rain forests are composed of four general layers of vegetation: canopy, sun seekers, understory, and forest floor.

The canopy is composed of tall trees which rise to a height of 100 feet or more. Their crowns form an interlocking canopy which absorbs the strong tropical sunlight, allowing as little as 1 % to reach the forest floor. They also buffer the forest floor from strong winds. Most of these trees have oval leaves with an elongated tip to "drip" rain down below to other levels of the forest.

Sun seekers compose the next layer. They are plants just below the canopy and these plants like to take advantage of the trees and their access to sunlight. Vines climb up the trunks of the trees from the dark forest floor, then sprawl out along tree branches once they near the canopy.

Another group of plants, called epiphytes, (literally "upon plants") also inhabit the upper tree trunks and branches. These plants, including ferns, mosses, lichens, orchids, bromeliads and even cacti do not actually live off the tree like parasites, but use it for mechanical support and access to sun and nutrient rich rainwater.

Epiphytes disperse their seeds by wind and often grow on top of one another: a fern on a moss on a lichen on a tree trunk. Because they are not in contact with the ground these " hangers-on" must conserve their own supplies of water and nutrients. Some orchids store water in bulbus stems. Tank bromeliads have large, water tight pockets, which can hold over two liters of water. Canopy trees have smooth or flaky bark to make it more difficult for sunlight-hungry vines and epiphytes to gain a footing.

Far below the canopy is the forest under story, a shady, humid and calm level of the forest. Shade adapted herbs, shrubs, and small trees grow to several meters in height. These plants germinate and grow to maturity in the absence of any direct sunlight, although they may include species adapted to take advantage of any gaps in the canopy. If a branch or tree falls, perhaps pulled down by heavy loads of epiphytes, the gap can create a sudden column of light, photosynthetic energy for any plant that can grow quickly to take advantage of the light before the canopy closes in again.

Mosses, ferns, seedlings and a layer of leaf litter lie on the forest floor. Below this fallen plant material lie tangled rootlets of forest trees and the pale strands of fungi, which rapidly decompose plant matter and recycle nutrients back into the forest. Many house plants are from the tropical regions of the world. Below you can see an examples of common house plants and their origin in the tropical regions of the world.

Plants that generally grow well in bottle environments include small leaf ferns, small bromeliads, small leaved ivies, mosses, liverworts, small sebum plants and small cacti.

Now that you have thought about diversity within tropical forests, think about how plants have adapted to a particular tropical climate or rain forest layer.

In determining what types of house plants to put in what layer of your tropical Ecocolumn, think of the leaf shape and size, tolerance to wind, light requirements, and flower and fruiting times.

Using your house plant knowledge, plant an Ecocolumn with common house plants. Each chamber can represent a different rain forest layer. You may have to simulate plants for some layer, providing sticks or other structural support for epiphytes, for example.

The following is a list of tips when constructing your Ecocolumn:

• Precipitation - Punch two or three small holes in the cap of a bottle top funnel in order to "water" your Ecocolumn. Note: you can also cap your Ecocolumn using a bottle top to or base in order to make a closed system.
• Air Holes - Poke plenty of air holes for the living creatures inside. You will need to keep the holes small so that fruit flies do not escape. In aquarium chambers be sure the air holes are made well above the water levels.
• Drainage Holes - The number and height of the drainage holes you poke will effect the environment in any soil-filled chamber. Sandy soil with holes poked low in the base of the chamber will mean quick drainage and drier conditions. Peaty soil and a few high drainage holes will make for wetter conditions. Create a variety of plant habitats by using different soils and drainage.
• No mistakes are possible - Remember, there is no right or wrong way to build an Ecocolumn. Change is a natural part of this experiment, so when things change, try to figure out what happened and why. If insects or plants die in your Ecocolumn, think again about the natural habitat of the living creature and what it might need to live.
• A few words of caution - Ecocolumns can become very top heavy and tip easily. Some people Velcro them to a wall. You can also weight the bottom with gravel or water. Avoid exposing Ecocolumns to full sunlight.

1. What parts of the plants in the Ecocolumn did you examine to determine their place in the ecocolumn?
2. What plant level is most fragile? Why?
3. Could one level of the forest be removed and the other parts of the forest still function properly?
4. Are there any rainforests in North America?
5. Name several rain forest animals that use special parts of their bodies to help them move around in the rainforest? For example, the spider monkeys grasping tail enables it to hold onto branches.
6. What are two products that come from tropical rainforests?

1. Design and construct a mural about the birds in your state and their dependence on the tropical forested regions of other countries.
2. Write a letter to a rain forest conservation organization and ask them what your class can do to help protect tracts of rain forest.
3. Keep a careful notebook as you plan your Ecocolumn. Record exactly what you have put inside. Once set up, keep a careful watch and written record of what the conditions are and how they change.

• Dreams of Amazonia, Roger D. Stone, Viking 1985
• The Enchanted Canopy, Andrew W. Mitchell, Macmillian 1986
• In the Rainforest, Catherine Caufield, Knopf 1985
• Tropical Rainforest, Arnold Newman, Facts on File 1990