Biomes & Aquatic Systems — Drills · Grade 12 Science

Chapter: Ecology, Populations & Biodiversity

What these drills covers

By the end of Biomes & Aquatic Systems you should be able to:

6 questions, multiple choice, numeric and written answer, each with a worked explanation.

Vocabulary used: biome, climate, estuary, photic zone, wetland, salinity.

Problem 1

A terrestrial biome is defined mainly by its
  1. latitude alone
  2. number of rivers
  3. soil color and wind speed
  4. climate — temperature and precipitation
Answer and explanation

climate — temperature and precipitation

Temperature and precipitation (climate) are the master controls that define a biome.

Problem 2

Warm year-round with a strong wet-and-dry season, dominated by grasses with scattered trees, describes the
  1. savanna
  2. tundra
  3. taiga
  4. temperate deciduous forest
Answer and explanation

savanna

That warm, seasonally dry landscape of grasses and scattered trees is the savanna.

Problem 3

The sunlit surface layer of a lake or ocean, where photosynthesis occurs, is the
  1. benthic zone
  2. photic zone
  3. permafrost layer
  4. profundal zone
Answer and explanation

photic zone

The photic zone is the sunlit upper layer with enough light for photosynthesis.

Problem 4

A salt marsh has an NPP of about 2,500 g/m²/yr; the open ocean about 125 g/m²/yr. About how many times more productive is the salt marsh?
Answer and explanation

20 times

2,500 ÷ 125 = 20 times greater.

Problem 5

Explain why wetlands are considered especially valuable ecosystems.
Answer and explanation

Wetlands are highly productive and support abundant biodiversity, and they provide key services: they filter pollutants and sediment out of water, recharge groundwater, and absorb floodwaters, protecting downstream areas. That makes their value reach far beyond the wetland itself.

Problem 6

As the climate warms, biologists expect terrestrial biome zones to
  1. stay exactly fixed in place
  2. disappear entirely overnight
  3. shift toward the poles and up mountainsides
  4. all convert to desert
Answer and explanation

shift toward the poles and up mountainsides

Because biomes track temperature and precipitation, warming shifts their zones poleward and upward in elevation.

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