UNIT 4 MODULE 2
INTERACTIONS Suggested time allotment 5-6 hours
KEY QUESTION
How does energy become transferred from one organism to another ?
CONNECTIONS PHYSICS: ENERGY( Radiant Energy)
GRADE 7
Components of an ecosystem: biotic and abiotic Ecological relationships
In this module Grade 8 students will learn the following: identify the roles of organisms in food chains and food webs.
conduct a simulation to investigate how energy is transferred from one source to another. Students will be able to:
sequence a food chain to show the transfer of energy from one trophic level to another trophic level identify the organisms comprising a food chain and the function of each identify the organisms comprising a food web and the function of each describe a food pyramid in terms of the amount of biomass or energy at each level analyze the relationship between energy and matter analyze the harmful effects of some farming practices to increase crop yield identify alternative agricultural practices which can minimize or possibly eliminate the problem that go with some farming practices
ACTIVITIES IN THIS MODULE
help students construct science ideas and develop science thinking skills through embedded questions. understanding of these concepts and skills will be strengthened through inquiry-based activities such as making observation, analyzing information and discovering on their own relationships and connections from the data gathered. concepts learned will prepare students to tackle more abstract science concepts about transfer of energy in higher grade levels particularly in the topic of photosynthesis and cellular respiration.
Activity 1 How do you identify the components of a food chain in an ecosystem? Activity 2 Making food webs Activity 3 Meat eaters vs. plant eaters
Activity 1
How do you identify the components of a food chain in an ecosystem?
Objectives: After performing this activity, you should be able to: 1. distinguish between producers and consumers. 2. analyze the transfer of energy from one organism to another. 3. construct a food chain in a given ecosystem.
Materials Needed: an article about “Monfort Bat Cave” Activity sheet
Procedure: 1. Read
an article about “Monfort Bat Cave.”
The Island of Samal, part of Davao del Norte Province, is off the coast of Mindanao. In this island is the Monfort Bat Cave which is approximately 245 feet (75 meters) long and has five entrances. Bats cover 75 percent of its ceilings and walls. An estimated 1.8 million bats, the largest known population of Geoffroy’s rousette fruit bats in the world, are overloading Monfort Bat Cave on the Philippines’ Samal Island.
Figure 1. Geoffroy’s rousette fruit bats clinging on walls and ceiling of the cave.
Geoffroy’s rousette fruit bats feed on fruit and nectar. Their role as pollinators and seed dispersers is essential in sustaining Philippine forests, including such important commercial fruits as durian. Each bat consumes 1½ to 3 times its body weight nightly in fruit and nectar. This colony could consume 550 tons (500,000 kilograms) of nectar from durian and other trees, pollinating an incredible number of flowers.
Worldwide, cave-dwelling bats are in alarming decline due to human disturbance and destruction of their cave roosts. In some areas, including Samal Island, bats are captured and eaten by humans. Colonies like the one in Monfort Bat Cave are now rare and in urgent need of protection. Their loss would endanger the health of forests and human economies.
The bat’s colony should be able to survive natural predators – crows, rats, 10-foot (3meter) pythons and occasional monitor lizards – just as bat populations do elsewhere. Untamed dogs and cats, however, also seem to do bat hunting at Monfort Bat Cave.
Q2. What are the organisms found in the surrounding area of Monfort Bat Cave? List them down in the table below. TABLE 1. ORGANISMS FOUND IN MONFORT BAT CAVE
PLANTS
ANIMALS
Q3. What group/s of organisms are considered as producers? Q4. What part of the durian trees and other trees served as food for the bats? Q5. The population of cave-dwelling bats is declining because they are being eaten by other organisms. What are these organisms that feed on bats? Q6. Among the organisms that feed on bats, are there organisms that possibly feed on the predators of bats? ___ Yes ___ No
3. Divide the organisms into the following categories as shown in the table below: Table 2. Categories of organisms living in the Monfort Bat Cave
Producers
1st order consumers
2nd order consumers
4. Based
on Table 2, construct a food chain with at least 3 organisms representing the producer, 1st order consumer and 2nd order consumer.
Q7. You have just analyzed the transfer of energy by categorizing the organisms according to their trophic level. In your own words, describe a food chain. Q8. Without decomposers, will producers and consumers stay alive? Why?
Q9. Without producers, will consumers stay alive? Why?
S cience Concepts
Basic Science Processes/skills
Integrated Science Processes or skills
Question 2
Observation
Identification
Question 3
Classification
Analyzing
Question 4
Observation
Identification
Question 5
Observing, Communicating
Question 6
Observing, Communicating
Question 7
Defining
Question 8
Communicating
Question 9
Communicating
Analyzing
Activity 2 -Making food webs Think of the food your family ate for supper last night. Make a food web based on your meal. Remember, your food web must have producers, consumers, and decomposers. Q10. To which group of organisms do you belong? Q11. Which trophic level do you occupy?
Figure 5. The idealized pyramids of biomass and energy show losses at each trophic level
Q12. Which group of organisms has the greatest biomass? Which has the greatest energy?
Q13. Which group of organisms has the least biomass? Which has the least energy?
Q14. What happens to the amount of biomass from the bottom to the top of the pyramid?
Activity 3 Meat eaters vs. plant eaters
What can you infer from the biomass pyramids below? 1. Study the following pyramid of biomass.
Figure 6.
Pyramid of biomass
Q15. How much biomass of humans can 5 000 kg of corn support? 2. This time, study the following pyramid of biomass.
Q16. How much biomass of chicken can 5 000 kg of corn support?
Q17. How much biomass of humans can the chickens support?
Q18. Which is more efficient in converting biomass of producers to biomass of consumers – a meat eater or a plant eater? Give your explanation.
Summary Energy flow in the ecosystem is a one-way process. Energy flows from the sun, to the producers, and to the consumers. An ecosystem consists of all the organisms in an area interacting with one another and the nonliving environment.
Producers such as plants, algae, and certain bacteria capture the energy of sunlight to produce food molecules. Consumers such as animals eat or consume producers and other organisms to obtain energy. The flow of energy between organisms can be shown by a food chain or a food web.
A food chain is a sequence of organisms used as food and the organisms that feed on them. It starts with a producer followed by a series of consumers. A food web shows the complex feeding interrelationships between organisms in an area. It consists of interconnected food chains. Energy flows through different feeding levels called trophic levels in food chains and in food webs. Producers occupy the first trophic level. Consumers are at succeeding trophic levels ending with the top or highest-level consumers.
A food chain or a food web can be arranged in the form of a pyramid. A pyramid of biomass shows the decreasing amount of matter or tissue while an energy pyramid depicts the decreasing amount of energy. The greatest amount of biomass or energy is at the base of the pyramid. The amount of biomass or energy decreases towards the top. While matter is recycled in ecosystems, energy flows only in one direction 1st order from producer to consumer to 2nd order consumer, etc. People are the top consumers in many food webs. To increase food production, they use methods which may disrupt food chains or food webs. They have to learn how to make decisions to correct these mistakes
Cycling of Materials in the Ecosystem
Content Standard: Demonstrate understanding of the cycling of materials in an ecosystem
LEARNING COMPETENCIES 1. Analyze the roles of organisms in the cycling of materials 2. Explains how materials cycle in an ecosystem
The Oxygen- Carbon Dioxide Cycle
The Water Cycle
The Nitrogen Cycle
Summary: 1. Producers make their own food and provide food to other organisms Consumers get their energy from the producers or from other organisms that eat producers. Decomposers break down dead materials so these simpler nutrients are returned to the soil and can be used again by the plants.
2.
Matter moves through the ecosystem in cycles.
Basic Science Processes Analyzing, Observing, Communicating, Identifying, illustrating
Thank YOU VERY MUCH LISTENING…..
