BOTTLE BIOLOGY-EXPLORING ECOSYSTEMS

Transcription

1 BOTTLE BIOLOGY-EXPLORING ECOSYSTEMS ECOSYSTEM AND HABITAT ECOCOLUMN DESIGN Experiment Objective: Students will design and construct an EcoColumn from a 2L pop bottle with two different types of ecosystems in it. Students will observe their ecosystems and habitats and record data concerning the observations they make over the week, changes in population, plant growth, water quality, and animal growth. Learning Goals: Students will construct ecosystems in a bottle. There also will be time to follow up on questions and experiences with their your aquatic and terrestrial habitats. Students will exercise important early scientific skills, like observing, measuring, classifying, communicating data, inferring, and predicting. Part 1: The Aquatic World in a Bottle. You will construct an aquatic habitat filled with various critters and aquatic plants. Explore the organisms and their interactions. Part 2: The Terrestrial World in a Bottle. You will build upon your bottle aquarium, adding a terrestrial habitat filled with soil, critters, and terrestrial plants. Explore the organisms and their interactions and how they compare to those in your aquatic habitat. LESSON IMPLEMENTATION OUTLINE Introduction: Water, as it cycles between land, ocean and atmosphere, forms the major link between terrestrial world (involving anything living on earth) and aquatic world (involving anything living on or in water). Water drips off rooftops, flows over roads, off your toothbrush, and down the drain, percolates through soils of fields and forests and eventually finds its way into rivers, lakes and oceans. During its journey, water will pick up leaf litter, soil, nutrients, agricultural chemicals, road salts and gasoline from cars, all of which have profound impacts on life in aquatic systems. Water can also be filtered or purified as it percolates through soil. Content Background: Ecosystems are dynamic interactions between plants, animals, and microorganisms and their environment working together as a functional unit. Ecosystems will fail if they do not remain in balance. No community can carry more organisms than its food, water, and

2 shelter can accomodate. Food and territory are often balanced by natural phenomena such as fire, disease, and predator numbers. Each organism has its own niche, or role, to play. The whole earth's surface can be described by a series of interconnected ecosystems. All living beings form and are part of ecosystems. They are diverse and always changing. Within an ecosystem, all aspects of the environment (both living things and non-living settings) interact and affect one another. Every species affects lives of those around them. Different areas in the world house different ecosystems. For example, you won't find an elephant or a tropical rainforest in Alberta! The different world ecological units are called biomes and they each have different flora, fauna, landscapes and weather patterns.

3 The Changing Ecosystem Ecosystems are not unchanging. Natural changes in climate will result in a change in environment, which results in a change in ecosystems. The influence of mankind can change the ecosystem. These influences may be direct or indirect. Direct influences are logging and agriculture where original vegetation is removed. Indirect influences result from global changes in environment caused by civilization, like global warming. In many cases, an ecosystem changes and may appear different. The first plants to grow were very hardy ones, such as lichens and grasses. These plants became established in the sand, silt and clay that covered the landscape. Their roots grew into cracks and helped to break down these mostly unfertile materials. When these plants died, the organic material in them combined with the sand and clay to form a simple soil. This soil allowed other types of plants to become established. As the soil layer grew deeper, larger and stronger plants became established, and some of the original plants were replaced. This replacement of some plant species with others, and the associated change in animal species, is called succession. An ecosystem that is in a stable state, or is not in the process of being succeeded by another, is known as a climax community. Natural processes such as fire, flooding, and insect invasion can disturb whatever plant and animal species are present, and radically change the local environment. The area then starts the successional sequence again, beginning with the pioneer species and building towards the climax community. In this way, the ecosystems are constantly being rejuvenated by the environment.

4 The ecological environment you will build involves where plants and animals living within one environment. This ecology demonstrates an environment in which two unrelated organisms co-exist over a long period of time. Water given to the potted material is filtered by the sand and seeps into the fish bowl. The cotton string acts as wick and keeps the plant growing by absorbing water back into the soil-no droughts. Carbon dioxide is produced by the fish and therefore absorbed by the plant on top. The plant uses this carbon dioxide to make carbohydrates during photosynthesis, which in turn releases more oxygen into the air used by the fish. Similarities between Terrestrial and Aquatic systems both ecosystems include communities made up of a variety of species, within both communities there are populations at the different trophic levels, a great deal of mutual interdependence exists between species in both terrestrial and aquatic environments, in undisturbed terrestrial and aquatic ecosystems equilibrium is reached, i.e. very few major changes are observed over a period of time, in both ecosystems stratification (vertical zonation) occurs. Differences between Terrestrial and Aquatic systems the aquatics are so rich in nutrients that they support more lives than equivalent terrestrial ecosystems. The small drifting photosynthetic organisms of the oceans, phytoplankton, are the major photosynthesizers, or primary producers of earth aquatic environments are much more stable than, with smaller fluctuations in temperature and other variables aquatic organisms are seldom exposed to desiccation while terrestrial organisms are often exposed to desiccation and are usually relatively resistant to drying out, oxygen is sometimes a limiting factor in aquatic habitats but this is seldom the case in terrestrial habitats light can be a limiting factor in some aquatic habitats, but in most terrestrial environments there is hardly ever a a shortage of light The basic components of the EcoColumn are soil, water and plants. Plants growing in the upper part of the column take nutrients from the surrounding soil and, with the aid of the wick, take water and other substances from the aquatic portion below. Substances you add to the terrestrial section will move down, or percolate, through the soil and drain into the aquatic section. Collected soil and water will likely contain algae, phytoplankton, plant seeds and insect larvae. Store-bought soil and tap water will include far fewer organisms. Terrestrial and aquatic plants are excellent indicators of change in your system. Fast-germinating and fast-growing plants will most effectively register change in a short period of time.

5 Vocabulary: Ecology-Plants, animals, and other living organisms living together with their environment. Carbon dioxide-from the respiration of living organisms and microorganisms Parasitism-Two organisms unrelated co-exist over a long period of time. Mutualism-Both species benefit from the interaction. Carbohydrates- Energy produced by plants through the process of photosynthesis Lab Activity Instructions: Students will perform the EcoColumn experiment individually or in pairs and can share ideas among each other. Instructors will explain with the materials for the experiment and model a quick demonstration of the terrestrial and aquatic ecosystems. Students are given the materials to construct and the opportunity to observe two ecosystems in one column. Allow one instructor for demonstration and other instructors as assistants around the classroom. Materials: 2L pop bottles (X2), water, duckweed, rocks, pebbles, water snails, sand, scissors, small terrestrial plants, soil, organic potting soil, cotton string, fish tank gravel, aqua plants, markers Aquatic Habitat Materials: Fine-grained aquarium gravel (provides bedrock ) Sand and topsoil (provides bottom sediment) Water (provides aquatic habitat) Pebbles, rocks, duckweed, sunken logs, and other miniature objects typical of an aquatic bottom Aquatic plants and animals-water snails, fish etc. Terrestrial Habitat Materials: Fine-grained aquarium gravel (provides bedrock ) Topsoil (provides soil substrate) Leaf litter (provides decaying materials) Dead tree leaves, rocks, twigs and other organics typical of a forest habitat Small terrestrial plants Procedure: 1. Remove label from a 2L bottle. Using scissors to cut the bottle 1cm below the shoulder of the bottle. You may draw the line first and then cut it 2. Poke or drill a hole in a bottle cap. 3. Thread a thoroughly wet thick water-absorbing string through bottle cap, and then invert the top and set into the cut base. The string should reach to the bottom of reservoir and thread loosely through the cap.

6 4. Fill reservoir with water. Add soil and plants to top chamber. To be effective, the string should run up into soil, not be plastered along a side of the bottle. For better drainage, place a layer of gravel, sand or vermiculite in the bottom of the soil unit. Make sure that the string touches the water of the aquatic system. For aquatic habitat: 1. Add a layer of sand or topsoil (2-3 cm) to deep base. 2. Add a layer of gravel (1-2 cm) on top of sand/ topsoil. 3. Plant aquatic plants with roots in sediment and add water. 4. Add floating aquatic plants. Let the aquarium sit until the sediment settles. Add aquatic animals. For terrestrial habitat: 5. Mix equal parts of leaf litter and topsoil together, moisten, and add a layer (6-8cm) over the gravel. 6. Plant terrestrial plants in the soil. Add terrestrial animals. 7. Arrange dead trees and other objects on soil. Note: Provide water and nutrients daily and change the water once a day, and water the soil. Checking for student understanding: Ask students to explain their two ecosystems, including all the living organisms and their environment. Encourage them to use concepts and terminology learned from the lesson. Invite groups to interact with one another and explain their ecosystems to each other. Extensions and connections: A simple model, a complex world: the bottle is a relatively simple model, but it allows you to focus on specific aspects of a complex world. Allow students to think about some environmental factors, such as temperature and nutrients, that can influence the ecology of the column. CURRICULUM CONCEPTS Ecology and Biology-Habitat, ecosystems, and interactions of living organisms References:

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