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Reporting Category 5: Interdependence within Environmental Systems

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do elements like carbon and nitrogen move through an ecosystem and get reused?

Describe how matter cycles through ecosystems, including the carbon, nitrogen, and water cycles, and explain the role of decomposers in returning nutrients (TEKS Biology, Reporting Category 5; energy and matter; systems and system models).
A TEKS-level answer on biogeochemical cycles for the Texas STAAR Biology EOC: how carbon, nitrogen, and water cycle through ecosystems, the role of decomposers, and why matter cycles while energy flows one way.
11 min answer →

How do communities change over time, and how do human activities affect ecosystems?

Explain primary and secondary succession, and evaluate how human activities such as pollution, habitat destruction, and resource use affect ecosystems and biodiversity (TEKS Biology, Reporting Category 5; stability and change; cause and effect).
A TEKS-level answer on succession and human impact for the Texas STAAR Biology EOC: primary and secondary succession, how communities change over time, and how human activities affect ecosystems and biodiversity, plus conservation.
11 min answer →

How does energy move through an ecosystem, and why is so little of it left at the top of a food chain?

Interpret food chains, food webs, and energy pyramids to explain how energy flows through an ecosystem and is lost at each trophic level (TEKS Biology, Reporting Category 5; energy and matter; using mathematics).
A TEKS-level answer on energy flow for the Texas STAAR Biology EOC: food chains and webs, producers and consumers, trophic levels, the energy pyramid and the 10 percent rule, and why energy is lost at each level.
12 min answer →

How do ecologists organize the living and non-living parts of the environment into levels?

Describe the levels of ecological organization from organism to biosphere, and distinguish the biotic and abiotic factors that make up an ecosystem (TEKS Biology, Reporting Category 5; systems and system models; patterns).
A TEKS-level answer on ecological organization for the Texas STAAR Biology EOC: the levels from organism to population, community, ecosystem, biome, and biosphere, and the difference between biotic and abiotic factors.
10 min answer →

What controls how large a population can grow, and what happens when it reaches that limit?

Analyze how limiting factors and carrying capacity affect population size, and interpret population graphs and predator-prey relationships (TEKS Biology, Reporting Category 5; cause and effect; stability and change).
A TEKS-level answer on population dynamics for the Texas STAAR Biology EOC: limiting factors, carrying capacity, reading population growth graphs, and how predator and prey populations affect each other.
11 min answer →