30 Questions
What is the key concept of Unit 1 in Ecology Science 9?
Systems
Which of the following is NOT one of the 4 essential biogeochemical cycles mentioned in the text?
Oxygen cycle
What is the main role of bacteria and decomposers in the biogeochemical cycles?
Breaking down dead organisms into raw elements
Which biogeochemical cycle involves the movement of water between different reservoirs?
Water cycle
Why is it important for materials to change states and transform in biogeochemical cycles?
To maintain balance in ecosystems
Which concept is NOT directly related to the biogeochemical cycles mentioned in the text?
Photosynthesis
What is the term used to describe the process of liquid water transforming into water vapor in the atmosphere?
Evaporation
During which time of the day do evaporation and transpiration mainly occur?
Daytime
When water droplets in clouds become large enough, what process results in them falling to the earth?
Precipitation
Which process involves surface water flowing on land and eventually returning to an ocean or lake?
Runoff
In the carbon cycle, which organisms use carbon dioxide from the air or water as a raw material to build organic molecules?
Photosynthesizing plants, algae, and bacteria
What is the term for the process by which water is absorbed by plants through their roots?
Transpiration
What is the role of nitrifying bacteria in the nitrogen cycle?
Converting nitrate to nitrogen gas
How do plants utilize nitrates and nitrites?
To make proteins
What is the process of assimilation in relation to nitrogen?
Absorption of nitrogen into organic compounds by plants
Which process involves the conversion of nitrate to nitrogen gas?
Denitrification
What is the significance of phosphorus in ecosystems?
It is necessary for building DNA molecules
How does phosphorus primarily enter the soil or water in the phosphorus cycle?
By gradual release from rocks and minerals
What is one way carbon can return to the atmosphere?
Decomposition of dead organisms
Which process releases CO2 into the air during volcanic eruptions?
Weathering and Erosion
What happens when dissolved CO2 in water exceeds its saturation point?
The dissolved CO2 goes back into the atmosphere
Which process leads to the formation of solid limestone?
Weathering and Erosion
What is a consequence of too much dissolved CO2 in water?
Acidification harmful to shellfish and corals
How does carbon enter the hydrosphere or geosphere through burial?
By sinking to the bottom of the ocean or being submerged in waterlogged areas
What happens to dead organisms under conditions where decomposers cannot break them down?
They get buried under sediment and the carbon gets locked in rocks.
Why do only plants have CO2 going both into and out of them in this system?
Plants are the only ones that undergo photosynthesis.
What is the role of nitrogen-fixing bacteria in the nitrogen cycle?
Combine atmospheric nitrogen with hydrogen to make ammonia.
Why does deforestation lead to an increase in CO2 levels in the air?
Deforestation prevents plants from photosynthesizing and taking up CO2.
What happens to carbon in rocks that are uplifted to the Earth's surface?
It remains locked in rocks indefinitely.
What is the primary function of ammonia produced by nitrogen-fixing bacteria?
To provide a source of nitrogen for other living organisms.
Study Notes
Unit 1 in Ecology Science 9
- The key concept is the biogeochemical cycles, which involve the movement of essential elements such as water, carbon, nitrogen, and phosphorus through the environment.
Biogeochemical Cycles
- The 4 essential biogeochemical cycles are: water, carbon, nitrogen, and phosphorus.
- The main role of bacteria and decomposers is to break down organic matter and release essential elements back into the environment.
- The water cycle involves the movement of water between different reservoirs, including evaporation, condensation, and precipitation.
- It's important for materials to change states and transform in biogeochemical cycles because it allows essential elements to be recycled and reused.
Water Cycle
- Evaporation is the process of liquid water transforming into water vapor in the atmosphere.
- Evaporation and transpiration mainly occur during the daytime.
- When water droplets in clouds become large enough, precipitation results in them falling to the earth.
- Runoff is the process of surface water flowing on land and eventually returning to an ocean or lake.
Carbon Cycle
- Photosynthetic organisms use carbon dioxide from the air or water as a raw material to build organic molecules.
- Absorption is the process by which water is absorbed by plants through their roots.
- One way carbon can return to the atmosphere is through respiration.
- Volcanic eruptions release CO2 into the air.
- When dissolved CO2 in water exceeds its saturation point, it forms carbonic acid.
- The formation of solid limestone is a result of the process of precipitation.
- Too much dissolved CO2 in water can lead to acidification.
- Carbon enters the hydrosphere or geosphere through burial.
- Under conditions where decomposers cannot break them down, dead organisms can be fossilized.
- Plants have CO2 going both into and out of them in this system because they use CO2 for photosynthesis and release CO2 through respiration.
Nitrogen Cycle
- Nitrifying bacteria convert ammonia into nitrate and nitrite.
- Plants utilize nitrates and nitrites by absorbing them through their roots.
- Assimilation is the process by which plants use nitrogen to build organic molecules.
- Denitrification is the process of converting nitrate to nitrogen gas.
- Nitrogen-fixing bacteria produce ammonia, which is used by plants to build organic molecules.
Phosphorus Cycle
- Phosphorus is significant in ecosystems because it is essential for plant growth and development.
- Phosphorus primarily enters the soil or water through the decomposition of organic matter.
- Deforestation leads to an increase in CO2 levels in the air because it disrupts the carbon cycle.
- When rocks are uplifted to the Earth's surface, carbon can be released into the atmosphere.
- The primary function of ammonia produced by nitrogen-fixing bacteria is to provide nitrogen to plants.
Explore the different ways in which carbon returns to the air, such as through respiration by living organisms, decomposition, volcanic eruptions, and through other processes. Test your knowledge on the carbon cycle and its impact on the atmosphere and biosphere.
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