🔬 7th Grade Science · Unit 3
Ecosystems
27 short narrated lessons in 5 chapters, each with pictures, a quiz with a hint and a second try, and an explanation for every answer.
Standards: MS-LS2-1 MS-LS2-2 MS-LS2-3 MS-LS2-4 MS-LS2-5
What your child will learn
Resources and populations
- Parts of an EcosystemIdentify the living and nonliving parts of an ecosystem.
- Populations and CommunitiesDistinguish between individuals, populations and communities.
- Limiting FactorsExplain how limited food, water and space affect population size.
- Reading Population GraphsAnalyze graphs of how populations grow and shrink.
- Resources and Populations Review ReviewReview how the availability of resources affects populations.
Interactions among organisms
- Competition: Sharing Limited ResourcesExplain how organisms compete for shared resources.
- Predators and Prey: Linked PopulationsDescribe how predator and prey populations affect each other.
- Mutualism: Partners That Both BenefitDescribe relationships in which both species benefit.
- Commensalism and ParasitismCompare relationships where one species benefits and the other is unaffected or harmed.
- Review: How Organisms Interact ReviewReview the patterns of interaction between organisms in different ecosystems.
Energy flow and matter cycles
- Producers, Consumers and DecomposersDescribe the role of each group in an ecosystem.
- Food Chains and Food WebsModel how energy moves through food chains and food webs.
- Energy PyramidsExplain why less energy is available at each higher level of a food web.
- The Carbon CycleModel how carbon cycles between living things and the environment.
- Decomposers Recycle MatterExplain how decomposers return nutrients to the soil.
- Energy Flow and Matter Cycles Review ReviewReview how energy flows and matter cycles among living and nonliving parts of ecosystems.
Ecosystems change
- Ecological SuccessionDescribe how communities change over time after a disturbance.
- Natural DisturbancesExplain how fires, floods and droughts affect populations.
- Human Changes to EcosystemsExplain how human activities can shift ecosystem populations.
- Invasive SpeciesDescribe how invasive species can disrupt an ecosystem.
- Ecosystems Change: Review ReviewReview evidence that changes to an ecosystem's parts affect its populations.
Biodiversity and ecosystem services
- What Is Biodiversity?Explain what biodiversity is and why it matters to ecosystem health.
- Services Ecosystems ProvideDescribe services such as clean water, pollination and soil formation.
- Protecting BiodiversityDescribe ways people protect species and habitats.
- Evaluating SolutionsEvaluate competing design solutions for maintaining biodiversity.
- Biodiversity and Ecosystem Services Review ReviewReview why biodiversity matters and how to evaluate ways to protect it.
- Unit 3 Test: EcosystemsShow what you learned in the whole unit (Resources and populations, Interactions among organisms, Energy flow and matter cycles, Ecosystems change, Biodiversity and ecosystem services) by answering mixed questions.
Try a question from this unit
From the lesson “Parts of an Ecosystem”
Which of these is an abiotic factor in a forest ecosystem?
Show the answer
sunlight reaching the forest floor. Sunlight was never alive, so it is abiotic. Fallen pine needles are tempting because they are no longer growing, but they came from a living tree, so they count as biotic.
Hint kids see after a wrong try: “Look for the one thing that was never alive at any point.”
Key words
- ecosystem
- biotic
- abiotic
- population
- community
- limiting factor
- carrying capacity
- data
- graph
- competition
- predator
- prey
- mutualism
- symbiosis
- commensalism
- parasitism
- consumer
- decomposer
- food chain
- food web
- energy pyramid
- trophic level
- carbon cycle
- nutrient cycle
Try these lessons in Kids Shelf
Narrated lessons, pictures and quizzes for every grade from K to 8. Works offline.
