9.6 Ecosystems, Biomes and Human Impact
Notes
Biomes are large regions with similar climate and life, such as tropical rainforest, desert, tundra, grassland, temperate forest and taiga.
- Biodiversity is the variety of life in an area. High biodiversity makes ecosystems more stable.
- Human threats: habitat destruction, pollution, invasive species, overharvesting, and climate change.
- Burning fossil fuels adds $\text{CO}_2$ to the air, strengthening the greenhouse effect and warming Earth.
- Fertilizer runoff can cause algal blooms that use up oxygen in water (eutrophication).
- Conservation: protected areas, reducing pollution, sustainable use of resources, and restoring habitats.
Practice
Zebra mussels arrived in the Great Lakes on ships and spread fast because they had no natural predators there. They are an example of:
Invasive species are introduced from elsewhere and often outcompete native species.
Fertilizer from farms washes into a lake. Algae grow quickly, then die, and fish begin to die. Why?
This is eutrophication; low oxygen suffocates fish.
Which human activity most directly increases the amount of carbon dioxide in the atmosphere?
Burning coal, oil and gas releases stored carbon as CO2.
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