Lesson Notes By Weeks and Term v4 - JHS 3
ECOSYSTEM
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ECOSYSTEM
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Subject: Science
Class: JHS 3
Term: 2nd Term
Week: 2
Grade code: B9.3.3.1.1
Strand code: 3
Sub-strand code: 3
Content standard code: B9.3.3.1
Indicator code: B9.3.3.1.1
Theme: SYSTEMS
Subtheme: ECOSYSTEM
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An ecosystem is the natural “system” where living things (plants, animals, microorganisms) interact with one another and with non-living things (water, air, soil, sunlight). In Ghana, understanding ecosystems helps learners explain real issues such as galamsey effects on rivers, bush burning, overfishing, deforestation, and pollution—and how these activities affect food supply, health, and livelihoods. This lesson is aligned to NaCCA Indicator B9.3.3.1.1 and the exemplars: researching ecosystem composition, describing interdependence, distinguishing ecosystem vs habitat, constructing food chains/webs, and predicting effects of disturbances.
A. What is an Ecosystem? An ecosystem is a community of organisms interacting with each other and with the physical environment in a particular area. Biotic components (living): Producers (autotrophs): green plants, algae (make their own food by photosynthesis) Consumers (heterotrophs): animals (eat plants/animals) Primary consumers: herbivores (eat plants) Secondary consumers: carnivores/omnivores (eat herbivores) Tertiary consumers: top predators Decomposers/detritivores: fungi, bacteria, earthworms, termites (break down dead matter) Abiotic components (non-living): sunlight, water, air (oxygen/carbon dioxide), soil, minerals, temperature, wind, pH, humidity
Worked Ghanaian example: Pond ecosystem (e.g., a small pond near a farm) Biotic: algae, water weeds, tadpoles, tilapia, insects, frogs, snakes, birds, bacteria Abiotic: water, sunlight, dissolved oxygen, mud/soil, temperature, nutrients (nitrates, phosphates)
B. Composition of an Ecosystem (What to Research) When learners “conduct research into the composition of an ecosystem,” they should collect information on: Type of ecosystem: terrestrial (land) or aquatic (water) Abiotic factors: rainfall, temperature, soil type, water quality, light intensity Biotic factors: producers, consumers, decomposers present Interactions: feeding relationships, competition, symbiosis Human activities: farming, fishing, mining, waste disposal, bush burning Evidence/data: observations, photos, simple counts, interviews, short videos, charts
Simple research method (school/community-friendly) Choose a local ecosystem: school garden, nearby stream, market refuse area, mangrove area, savanna grassland. Observe and list organisms seen (morning and afternoon if possible). Note abiotic conditions (sunny/cloudy, soil wet/dry, presence of litter, water colour). Take photos (phone) or draw sketches. Present findings in a table: *Organism → role (producer/consumer/decomposer) → interaction*.