This lesson explains major human activities that change marine and freshwater ecosystems, how those activities affect water quality, habitats, and species, and practical, science-based solutions. It uses Canadian examples and encourages students to think about short-term gains versus long-term ecological costs and actions they can take.
Human Practices Impacting Marine and Freshwater Ecosystems — Grade 8 Level "We changed the landscape, and the water is answering back." — Your slightly ominous but accurate science TA Hook: Picture This You stand on a lakeshore where ducks used to waddle happily. Now there are ugly g...
This lesson builds on what you learned about Biodiversity in Water Systems and the ways natural forces shape the Canadian landscape. Remember how rivers, glaciers, and erosion move stuff around? Now think about how people move stuff — fertilizers, concrete, boats, nets — and how those choices ripple...
What we're covering (fast roadmap) Major human activities that change marine and freshwater ecosystems How each activity affects organisms, food webs, and water quality Real Canadian examples you can actually picture Simple actions and science-based solutions that work Big idea: People...
1) Agriculture: fertilizer, pesticides, and runoff What happens: Fertilizers (nitrogen and phosphorus) wash off fields into streams and lakes. The science: Extra nutrients fuel algal growth — rapid algae population booms called algal blooms . The drama: When algae die and decompose, microbes g...
2) Urbanization and stormwater runoff What happens: Roads, parking lots, and roofs channel oil, heavy metals, salt, and trash into waterways. The effect: Pollutants harm organisms and can change water chemistry; increased runoff also causes erosion and temperature changes. 3) Wastewater and se...
4) Dams and water diversion What happens: Rivers get chopped up; flow and sediment transport change. The effect: Fish migration blocked (think salmon), altered habitats downstream, reduced nutrient flow to coastal ecosystems. 5) Fishing pressure and overharvesting What happens: Too many fish...
7) Plastic pollution and boating What happens: Plastics break into microplastics; boats spread invasive species and cause shoreline erosion. The effect: Ingestion and entanglement by wildlife; microplastics enter food chains. 8) Climate change (the amplifier) What happens: Warming temperatur...
Quick table — Common practice, typical impact, better move Human Practice Typical Ecological Impact Better/Science-backed Solution Excess fertilizer use Algal blooms, hypoxia Buffer strips, reduced application, cover crops Building on wetlands Lost habitat, worse floods Protect w...
Questions to make your brain do push-ups Why do ecosystems often respond slowly to damage, and then suddenly collapse? If a river's flow is halved by a dam, which species benefit and which suffer? Imagine your town plans a new housing development next to a wetland. What would you recommend...
Closing — The important vibe check Human practices can tip water ecosystems toward collapse or recovery. The difference often comes down to planning, respect for natural systems, and listening to science. You've already learned how natural forces shape landscapes; now think of human actions as...
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