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MassachusettsBiology

Module 6: Ecology and ecosystems

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do carbon and other matter cycle through an ecosystem, and what role do decomposers play?

Develop a model of how matter (especially carbon) cycles through an ecosystem via photosynthesis, feeding, respiration, and decomposition, and contrast the cycling of matter with the one-way flow of energy (MA STE HS-LS2-4, HS-LS2-5, energy and matter).
A standard-level answer on matter cycling for the Massachusetts High School Biology MCAS: how carbon cycles through an ecosystem by photosynthesis, feeding, respiration, and decomposition, the role of decomposers, and how matter cycling differs from one-way energy flow under HS-LS2.
11 min answer →

How do species interact in an ecosystem, and how do these relationships affect populations?

Describe the main ecological interactions (competition, predation, and symbiosis: mutualism, commensalism, parasitism) and explain how they affect the populations involved (MA STE HS-LS2-2, HS-LS2-6, cause and effect).
A standard-level answer on ecological interactions for the Massachusetts High School Biology MCAS: competition, predation, and the three kinds of symbiosis (mutualism, commensalism, parasitism), and how each affects the populations involved under HS-LS2.
11 min answer →

How is an ecosystem organized, and how do its living and nonliving parts interact?

Describe the levels of ecological organization (organism, population, community, ecosystem) and explain how biotic and abiotic factors interact to shape an ecosystem (MA STE HS-LS2-1, HS-LS2-2 supporting, systems and system models).
A standard-level answer on ecosystem structure for the Massachusetts High School Biology MCAS: the levels of ecological organization, biotic and abiotic factors, and how the living and nonliving parts of an ecosystem interact under HS-LS2.
11 min answer →

How does energy move through an ecosystem, and why does so little reach the top of a food chain?

Explain how energy flows through an ecosystem from producers to consumers along food chains and webs, and use the idea that only about 10 percent of energy passes between trophic levels to interpret energy pyramids (MA STE HS-LS2-3, HS-LS2-4, energy and matter).
A standard-level answer on energy flow for the Massachusetts High School Biology MCAS: how energy moves from producers to consumers along food chains, why only about 10 percent passes between trophic levels, and how to read energy pyramids under HS-LS2.
12 min answer →

How do human activities affect ecosystems and biodiversity, and how can we reduce the harm?

Explain how human activities such as habitat destruction, pollution, overexploitation, and climate change affect ecosystems and biodiversity, and evaluate solutions that support sustainability (MA STE HS-LS2-7, HS-LS4-6, stability and change).
A standard-level answer on human impact for the Massachusetts High School Biology MCAS: how habitat destruction, pollution, overexploitation, and climate change affect ecosystems and biodiversity, and how to evaluate solutions that support sustainability under HS-LS2 and HS-LS4.
11 min answer →

What controls the size of a population, and what is carrying capacity?

Explain how limiting factors and carrying capacity control population size, and interpret population growth curves, distinguishing exponential from logistic growth (MA STE HS-LS2-1, HS-LS2-2, stability and change).
A standard-level answer on population dynamics for the Massachusetts High School Biology MCAS: how limiting factors and carrying capacity control population size, and how to read exponential and logistic growth curves under HS-LS2.
11 min answer →