California Science Standards:
3rd Grade, Life Sciences (3a,b,c,d) Adaptations in physical structure or behavior may improve an organism’s chance for survival.
4th Grade, Life Sciences (2a,b,c) All organisms need energy and matter to live and grow.
6th Grade, Life Sciences (5a,b,c,d,e) Organisms in ecosystems exchange energy and nutrients among themselves and with the environment.
Objectives:
- Students will gain an understanding of ecosystems and the relationships between producers, consumers and decomposers.
- The food web will also provide an understanding of impacts on ecosystems and their lasting effects.
- Students will recognize that individuals or business that pollute, also called "stakeholders", sometimes reject the burden of sole responsibility, instead favoring shared responsibility through laws and taxes.
Introduction: In this activity students will select an organism to represent, then using a ball of yarn create a web of connections between producers, consumers and decomposers. Biodiversity in California’s coastal wetands is very high due to many ecological niches formed where habitats meet. Fresh water in rivers and streams becomes brackish and then salty as it meets the ocean. Coastal forests meet grasses on the banks of streams and then transition to algae and salt-tolerant plants. California coastal wetlands are stopping grounds for hundreds of thousands of migrating birds along the Pacific Flyway. Tides bring nutrients and sediment in and out of wetlands where many fish and invertebrates thrive. Of course we know that every organism in a wetland eats something and in turn is eaten by something else, and has many defenses and strategies to survive and reproduce. This activity explores those characteristics.
Producers – Producers are organisms, like green plants, that produce organic compounds from inorganic compounds. These are also a type of autotroph. An autotroph is an organism that makes its own food from inorganic substances. Then green plants, for example, are eaten by consumers in this case, grazing animals like the zebra.
Consumers – A consumer is an organism that obtains nutrients from other organisms. This is also a heterotroph. A heterotroph is an organism that cannot synthesize their own food and must obtain it ready made.
Decomposers - A decomposer is an organism of decay. These are also called saprobes. They break down the remains of dead animals and plants, releasing the substances that can be used by other members of the ecosystem.
Consumers – A consumer is an organism that obtains nutrients from other organisms. This is also a heterotroph. A heterotroph is an organism that cannot synthesize their own food and must obtain it ready made.
Decomposers - A decomposer is an organism of decay. These are also called saprobes. They break down the remains of dead animals and plants, releasing the substances that can be used by other members of the ecosystem.
Materials:
- Ball of yarn, hole punch, scissors
- Cerritos Marsh Animal/Plant Cards
- Distribute one plant/animal card to each student.
- Each student will punch two holes in each card. With a short piece of string make the card into a necklace.
- Have students review their animal/plant: what it eats, what eats it, it’s adaptations and where in the habitat it lives. Then have students sit in a circle.
- The student with the sun card sits in the middle with the ball of yarn.
- Start with any student and ask them to state aloud where their animal/plant lives and what it eats.
- That student takes the ball of yarn, holds on to one end, and rolls it to the animal or plant that it eats.
- The student that receives the ball of yarn will state aloud where their animal/plant lives and what it eats. That students then takes the ball of yarn, holds onto a piece of it, and rolls it to the next plant/animal in the food web.
- If the web ends, then cut the string and pick another animal to start with.
- After a while the class will have a range of webs. Begin adding effects to the web, such as – what if pesticides kill invertebrates? Everyone attached to the invertebrates must put down the string and stand up. Other effects to mention to the class include: What if too much silt smothers plants? What if the water quality is impaired by urban runoff? What if large amounts of plastic bags sink and cover clams and snails living in sediment?
- Are any plants or animals separate from other living things in a habitat?
- How does the landscape (mountains or deserts) or availability of water (deserts, wetlands) affect the food web? What kinds of adaptations do organisms have to survive in a wetland?
- What kinds of adaptations do organisms have to get food or avoid becoming food in a wetland?
- Ask students to design their own food web with themselves in the middle. What do you eat? What else relies on that food, what does that food eat, where does that food live
Extensions:
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