Coaching Centre
Chapter 3: Ecosystems Notes
How carbon and nitrogen cycle through ecosystems, photosynthesis and cellular respiration, relationships between organisms, how ecologists measure populations, what makes populations change, and how First Nations knowledge helps manage ecosystems sustainably.
Sections
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3A Matter cycles and the carbon cycle Mastered
Why matter cycles while energy flows through ecosystems, the stores and processes of the carbon cycle, how human activity is changing it, and what rising carbon dioxide means for climate and oceans.
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3B The nitrogen cycle Mastered
Why living things need nitrogen, how bacteria and lightning fix nitrogen from the air, nitrifying and denitrifying bacteria, legumes and fertilisers, and what happens when too much nitrogen reaches waterways.
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3C Leaves, light and water Mastered
Which colours of light chlorophyll and other leaf pigments absorb, the trade-off between taking in carbon dioxide and losing water through stomata, and how Australian leaves, C4 grasses and CAM plants are adapted to shade, heat and drought.
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3D Cellular respiration Mastered
The stages of aerobic respiration, ATP, what the energy is used for, anaerobic respiration in muscles and yeast, net gas exchange and the compensation point, shown with indicator tube experiments.
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3E Relationships between organisms Mastered
Relationships within a species and between species: competition, predation, parasitism, mutualism and commensalism, the meaning of symbiosis, and how predator and prey populations rise and fall together.
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3F Measuring populations and biodiversity Mastered
What populations, communities and biodiversity are, and how ecologists estimate population size with quadrats, transects and capture–recapture, with worked examples.
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3G What changes populations Mastered
How populations grow and level off at the carrying capacity, boom-and-bust cycles such as mouse plagues, and how limiting resources, seasons, disease, drought and human activity change population sizes, with Australian case studies.
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3H Caring for Country and sustainability Mastered
How First Nations peoples have managed ecosystems sustainably for tens of thousands of years, including the Brewarrina fish traps and Anangu habitats and seasons, savanna fire management and carbon, and how these ideas shape sustainable management today.
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3I Ecosystems review Mastered
A summary of the whole Ecosystems chapter, key words, and a mixed test covering the carbon and nitrogen cycles, photosynthesis, respiration, relationships between organisms, measuring and changing populations, and caring for Country.