Ecology and Biomes Quiz

Grade 9 · Science · Quiz

Test your understanding of ecosystems, biomes, food webs, and ecological relationships.

Questions

1. Which biome is characterized by permafrost, extremely cold temperatures, and low biodiversity?

   1. Taiga
   2. Tundra
   3. Temperate Deciduous Forest
   4. Desert
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   Answer: Tundra

   The tundra has permanently frozen subsoil (permafrost), very short growing seasons, and supports limited biodiversity — mainly lichens, mosses, and migratory animals.

2. In a food web, organisms that make their own food through photosynthesis are called:

   1. Primary consumers
   2. Decomposers
   3. Producers
   4. Secondary consumers
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   Answer: Producers

   Producers (autotrophs like plants and algae) make their own food via photosynthesis. All other organisms in a food web depend on them as the energy source.

3. A symbiotic relationship where both species benefit is called mutualism.

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   Answer: True

   Mutualism is a symbiotic relationship where both species benefit (e.g., bees and flowers). Commensalism benefits one with no effect on the other; parasitism benefits one at the other's expense.

4. Which of the following is an example of a keystone species concept — a species whose removal would drastically alter the ecosystem?

   1. Earthworm in soil
   2. Sea otter in a kelp forest
   3. Sparrow in a meadow
   4. Domestic cat in a suburb
   Show answer

   Answer: Sea otter in a kelp forest

   Sea otters eat sea urchins, which eat kelp. Without otters, urchin populations explode and destroy the kelp forest — a classic keystone species example studied by ecologist Robert Paine.

5. Energy transfer between trophic levels in an ecosystem is approximately:

   1. 90% efficient
   2. 50% efficient
   3. 10% efficient
   4. 25% efficient
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   Answer: 10% efficient

   The 10% rule states that roughly 10% of energy is transferred to the next trophic level; the other 90% is lost as heat, movement, and metabolic processes.

6. The role an organism plays in its ecosystem, including what it eats and how it interacts with others, is called its ___.

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   Answer: niche

   An ecological niche includes an organism's habitat, diet, behavior, and interactions. Two species cannot occupy the same niche indefinitely (competitive exclusion principle).

7. The tropical rainforest biome is best described as having:

   1. Low rainfall and high biodiversity
   2. High rainfall and high biodiversity
   3. Moderate rainfall and low biodiversity
   4. Seasonal drought and sparse vegetation
   Show answer

   Answer: High rainfall and high biodiversity

   Tropical rainforests receive over 200 cm of rainfall annually and harbor more than 50% of Earth's species, making them the most biodiverse terrestrial biome.

8. Decomposers, such as fungi and bacteria, are considered consumers in an ecosystem because they eat other organisms.

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   Answer: False

   Decomposers are not classified as consumers — they break down dead organic matter through chemical decomposition rather than ingesting whole organisms. They occupy their own trophic category.

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