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WorksheetsSA4 Biogeochemical and Succession Practice
Total questions: 25
Worksheet time: 14mins
Which two events would cause primary succession?
Forest clear-cut
Tornado winds
Lava flow
Major flood
Glacier retreat
Why does secondary succession recover faster than primary?
More producers present
Rocks provide habitat
Water collects faster
Soil and seeds already exist
Which events lead to primary succession and which to secondary succession?
Lava forming new land
Primary
Forest fire clearing an area
Secondary
Glacier retreat exposing bare rock
Primary
Abandonment of farmland
Secondary
Flooding of an area
Secondary
At the start of succession, how does species diversity compare?
Higher in primary, since competition is lower
No difference — both begin lifeless
Higher in primary, since bare rock offers niches
Higher in secondary, since soil already has seeds
After a hurricane blows down trees in a coastal forest, what type of succession occurs and why?
Primary — only bare rock remains
Secondary — life once existed and soil remains
Primary — all organisms were eliminated
Secondary - new sunlight exposure creates habitats
Which has greatest diversity?
New volcanic island
1-year abandoned field
Mature rainforest
Mowed lawn
Which pioneer organisms are most likely to colonize bare volcanic rock and begin soil formation?
Insects
Lichens
Ferns
Small shrubs
On a new volcanic island, what is the correct order of succession?
Bare rock → lichens/moss → grasses/shrubs → forest
Forest → grasses/shrubs → bare rock → lichens/moss
Lichens/moss → forest → bare rock → grasses/shrubs
Grasses/shrubs → bare rock → lichens/moss → forest
Which scenario most harms the nitrogen cycle and reduces plant growth?
Increasing legumes in a field
Planting crops that don’t require nitrogen
Decreasing nitrogen-fixing bacteria in soil
Regulating fertilizer use
If decomposers decrease, what happens?
Wastes → carbs
Energy for producers rises
Nutrients stop recycling
CO₂ levels fall
Soil samples show more antibiotics, which kill helpful bacteria. How would this affect the nitrogen cycle?
Less nitrogen fixation occurs
Faster return of nitrogen to air
Plants stop needing bacteria
Too many nitrates/ammonia build up
In an aquarium, what reduces nitrates?
Fish
Plants
Nitrobacter
Water
In the carbon cycle, autotrophs mainly:
Use oxygen to make food
Absorb water for energy
Convert carbon dioxide into glucose
Feed on herbivores
Which activity adds carbon dioxide to the atmosphere?
Using a wind turbine
Collecting solar energy
Burning wood for fuel
Running a hydroelectric dam
Which lowers atmospheric CO₂?
Burning coal
Burning logs
Animals eating fungi
Planting trees
Which raises CO₂?
More photosynthesis
Less animal respiration
More fossil fuel burning
Less deforestation
Which step of the water cycle is when plants release water vapor through their leaves?
Evaporation
Condensation
Transpiration
Precipitation
After heavy rains, a farm lake develops algae blooms. Which step in the phosphorus cycle caused this?
Fertilizer runoff carried phosphorus into the lake
Phosphorus condensed from air into rain
Rocks absorbed excess phosphorus
Fish directly released phosphorus
Which ecosystem recycles phosphorus faster?
Rocky soil — weathering releases phosphorus
Sandy soil — phosphorus evaporates
Rocky soil — plants take phosphorus from rock
Sandy soil — phosphorus dissolves into water
What is a major difference between the nitrogen cycle and the phosphorus cycle?
Nitrogen cycles through the atmosphere; phosphorus rarely does
Nitrogen only exists in rocks; phosphorus only in the air
Nitrogen is never used by plants; phosphorus is
Nitrogen is in ATP; phosphorus is not
In a closed ecosystem, why does oxygen stay balanced?
Plants and animals both consume oxygen equally
Plants produce oxygen; animals use oxygen
Oxygen is created by decomposers
Oxygen levels remain unchanged naturally
A deer carcass decomposes in a meadow. What happens to oxygen in the area?
Oxygen rises when decomposers die
Oxygen drops as decomposers respire
Oxygen remains constant inside tissues
Oxygen changes into nitrogen gas
After heavy rainfall, groundwater levels rise. Which process explains this?
Evaporation increased groundwater
Rainwater soaked into soil and recharged groundwater
Runoff carried away water and reduced recharge
Condensation trapped water underground
Photosynthesis links which cycles?
Carbon
Oxygen
Water
Nitrogen
Logging reduces transpiration & oxygen, raises carbon dioxide. Which cycles were disrupted?
Oxygen, carbon, water
Water & nitrogen
Phosphorus & oxygen
Nitrogen, sulfur, water
