HOW DOES YOUR GARDEN GROW?

Lesson 1: Plant biodiversity

Aim:  What characteristics do scientists use to divide the world into biomes?

Do Now: Using classroom resources, list the eight major biomes.

Answer: The six land biomes are as follows: The tundra, coniferous forest, deciduous forest, tropical rain forest, grassland, and desert.  There are two aquatic biomes, ocean and freshwater.

Motivation:  Show the class examples of mini-habitats that have been set up in the classroom.   A salt-water aquarium, pond-life ecosystem, a desert biome, a rotting log in a simulated tropical rain forest, a grassland or deciduous forest biome are only a few suggestions.  A butterfly habitat, worm compost container and/or plants grown by hydroponics can help to demonstrate interdependence among living things within their environments. 

Discussion: 

1.         Scientists classify biomes by climate and distinct communities. Freezing, hot, wet or dry climates attract different varieties of plants, animals and other organisms. All biomes have producers, consumers and decomposers.  Producers are green plants that make their own food through the process of photosynthesis.  Consumers depend on producers for food since they cannot make their own.  Decomposers break down dead plants and animals into simpler substances and return important nutrients to the soil. Review heterotrophic organisms (parasites and saprophytes), with the students

2.          About one percent of the Earth’s 250,000 different plant species have been examined so far, by scientists.  It is important that wild plants do not become extinct before they can be examined. These plants may provide the cures for diseases, such as cancer, that exist today. The fruits and vegetables that grow on our farms were once domesticated from wild plants. As land becomes scarce innovation is needed to produce large quantities of food in less space.   Hydroponics can be a solution.  Farming in nutrient rich solutions rather than in soil will use less space.  In the future, farmers may be able to grow crops in ponds and lakes.  

3.        Living things do not exist alone.  Living organisms interacting together in the same place make up a community.  The place where a population lives and grows is known as its habitat.  A niche is the role an organism plays in its community. Everything an organism does during its day to day living happens in its niche.  When things change within the community, for example, a species becomes depleted or extinct, the entire population can be affected. In the tropics, orchids attach themselves to the branches of tall trees. The trees lift them above the canopy (the top layer of the forest) where they can obtain sunlight needed for  photosynthesis. The rain forest is the habitat for the orchid and its niche is the tall tree were it lives, grows and carries out daily activities.

4.        The biomes of our world are determined by climate.  Tundras, which are very cold and dry are found in northern latitudes and peaks of mountains above the tree line. Mosses and grasses are found there.  Coniferous forests are abundant all across Canada, Alaska and areas of northern latitudes.  Pines, spruces and firs can survive in this climate.  Deciduous forests are found in the northeast United States, Canada and areas of mid-latitudes. Leaves fall from these trees during the change of seasons. Examples of tree life include oak, hickory, maple and birch. Tropical rain forests are found near the equator. These areas get at least 200 centimeters of rain yearly and are home to palm trees, vines, ferns and orchids. The climate is hot and humid in the rain forest.

Grassland biomes (savannas) are located in Africa, western North America or areas of mid-latitudes.  The summers are long and hot and the winters are cold.  Many species of grasses are found there.  Desert biomes receive less than 25 centimeters of rain yearly.  Cactus, yuccas and other plant life that can survive with limited rain. South America, Australia, western North America, northern China and most of North Africa have deserts. 

5.     The two types of water biomes are ocean and freshwater.  Oceans or marine biomes cover almost three quarters of the earth.  Most organisms live near the shore or close to the surface of the water to obtain sunlight for photosynthesis.  Freshwater biomes can have water that is standing or  moving.  Organisms that live in rivers adapt by clinging onto rocks or anchoring themselves on the bottom of the river.  In ponds, lakes, and swamps, organisms will survive with the correct temperature, food, sunlight and oxygen. 

Demonstration:  This project will require several days to complete. The projects should be kept in class for the duration of this assignment.  The children should be encouraged duplicate their work and make individual biomes at home for observation and investigation.  Some activities will be carried out independently to reinforce classroom skills.  Each group will work together to create a biome or habitat. The teacher can assign a different biome to each group.  The students are to search for information about their biome independently and share their information with their group.  They will decide what kind of plants, insects, fish, animals or organisms are needed to make their project as realistic as possible.  Working in a group setting will foster caring and sharing in a cooperative and learning environment.

A large, clear, plastic take-out container with a cover can be used as well as any recyclable container or shoebox.  A clear layer-cake container with a plastic tray and dome-cover provides good storage for a rotting log or tropical rain forest. The shoebox can be used if plastic wrap is placed under the sand or soil and water is used sparingly.  Fill the container with 2 to 3 centimeters of water, soil or sand, depending on the habitat. Add seeds, plants, rocks, living and non-living things based on your research. Plastic insects, silk butterflies or pictures of the animals found in the different biomes can be added when it is not possible to use living things. If small fish or insects are included, appropriate food should be used to help sustain them.  The proper amount of light, temperature and water should be provided as needed in each biome.  For example, a rain forest has low light, moist soil and a warm temperature.

The students in each group are to collaborate together on all aspects of this project.  Observing, problem solving, maintaining and evaluating the biome is a team effort.  A log is to be kept by each student on the team. Graphs can be included to measure plant growth.  Daily or weekly observations, changes within the biome and captioned drawings illustrating the changes should be included in the student’s log.  The group will present their research to the class upon completion.  Each student will be responsible for one part of the report.  The cover should display creative artwork and may be designed by one member or the entire team.  Data from the journal should be presented in narrative form. The report must include the geographic location of the biome and the weather pattern found there. Any other important factors, such as how the organisms interact with each other within the biome should be included in the report. 

 During the course of this project each student is expected to take turns visiting The American Museum of Natural History web site to answer the question “What are the three kinds of biodiversity?”  The answer can be written in their logbooks.  In addition, the children should explore one of the following links on the web site and provide a summary of their findings. 1) Where are you on this biodiverse planet?  2) Is biodiversity good for kids? 3) Here’s what’s happening to biodiversity  or 4) EXTINCTION. This assignment can be given for homework. If the internet is not available for all students, it is possible to print out the information from the web site and make copies for the children to read.

 Summary: The disruption of ecosystems and loss of biodiversity threaten the purity of our drinking water, the air we breathe, the food we eat, and the medicines we use. Pollution of wetlands, farming and the destruction of forests contribute to the depletion of our biomes.  It is important that wild plants do not become extinct before they can be examined.  They may provide a cure for diseases.

Note: This lesson was fun and informative.  I discovered that several students wanted to duplicate the project and make their own biomes at home. One student went so far as to make six different biomes!  

Evaluation-Test Yourself: Answer the following questions.  1)A group of interacting populations_____________.  2) Organisms that make their own food___________.  3)  A series of organisms in which each is food for the next____________. 4) Tundra, grasslands, coniferous and deciduous forests are examples of ______________. 5)  A very cold climate where few trees grow and the ground is often frozen______________. 1)  COMMUNITY    2)  PRODUCERS     3)  FOOD CHAIN

4) BIOMES       5)  TUNDRA           

New York State Performance Standards:  For more ideas see The Board of Education City of New York, Performance Standards in Science (first edition). Life Sciences Concepts: (New Standards) The students produce evidence that demonstrates their understanding of characteristics of organisms, such as the relationship between structure and function.  They will learn how organisms are interdependent in their environment by completing the biome.  The children will acquire information from multiple sources and present data in a narrative form and in artwork.

Note:  A team interdisciplinary project can strengthen the students understanding of  biomes and diversity of populations by incorporating, social studies, language arts skills mathematics lessons with a common theme while this unit is covered in science.

Homework: Construct a food web using animal or ocean life.  Explain the role each organism plays in the web. You can find information in your textbook or on the Internet. 

Additional Links:

www.amnh.org/science/biodiversity. American Museum of Natural History is the web site to use for this research. 

It takes all kinds, Growing Ideas, National Gardening Association www.garden.org, this is a journal of garden-based learning resources for teachers.

 www.scholastic.com, then click on the following: (1) teachers (2) online activities (3) science (4) grades 4-8 (5) Science Research Expedition: Tracking Mexico’s Wild Cats  (6) Discover the interactive food web.  Students will be able to view a food web that they can use for their homework assignment.

Materials: large storage containers, soil, sand, pond water, several heat lamps, assorted seeds, plants and rocks, gravel, insects and small fish, when necessary, artificial flowers and plants, paper and plastic models are acceptable. Note: This lesson can be broken down into several smaller lessons, so the children will not be overwhelmed by too much information.