Decomposition and Nitrogen Cycle Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of decomposers in an ecosystem?

To return elements from dead organisms back to the environment. (correct)

To facilitate photosynthesis in plants.

To provide energy for primary consumers.

To convert atmospheric nitrogen into nitrates.

Which of the following conditions would most likely slow down the rate of decomposition?

A humid, warm environment lacking oxygen.

A warm, moist environment with plenty of oxygen.

A dark, moist environment with high oxygen levels.

A cold, dry environment with limited oxygen. (correct)

Why is atmospheric nitrogen not directly usable by plants?

It is an inert gas that won't react with anything. (correct)

Plants are unable to absorb gases in their roots.

It needs to bond with other elements first.

It is too reactive in its gaseous form.

What is the role of nitrifying bacteria in the nitrogen cycle?

To turn ammonia in decaying matter into nitrites and then nitrates. (B) Signup and view all the answers

How does lightning contribute to the nitrogen cycle?

It provides energy for nitrogen and oxygen to react and make nitrates. (D) Signup and view all the answers

Which process turns nitrates back into nitrogen gas ($N_2$)?

Denitrification (B) Signup and view all the answers

How does storing food in a refrigerator help to preserve it?

It lowers the temperature, slowing down microbial activity and reproduction. (D) Signup and view all the answers

What is the role of decomposers in the nitrogen cycle?

To break down proteins in rotting matter and convert it into ammonia. (D) Signup and view all the answers

What is the primary function of nitrogen-fixing bacteria in their symbiotic relationship with legume plants?

To convert atmospheric nitrogen into a usable form for the plant. (A) Signup and view all the answers

Which process describes the conversion of water from a gaseous state to a liquid state in the water cycle?

Condensation (A) Signup and view all the answers

What is the method of desalination that uses pressure to force water through a partially permeable membrane?

Reverse osmosis (C) Signup and view all the answers

What is the primary goal of reforestation efforts in relation to biodiversity?

To increase the variety of plant and animal life in deforested areas. (A) Signup and view all the answers

Which of the following is NOT a benefit of maintaining biodiversity?

Providing natural habitats for introduced species. (B) Signup and view all the answers

What is the ONLY process by which carbon enters the carbon cycle from the atmosphere?

Photosynthesis (C) Signup and view all the answers

What process releases carbon dioxide back into the atmosphere from decaying organic matter?

Decomposition (A) Signup and view all the answers

What is the primary purpose of using a quadrat in the study of ecosystems?

To measure the percentage of distribution within an ecosystem. (C) Signup and view all the answers

Which of the following is a biological factor that can reduce food security?

Increased consumption of meat and fish (A) Signup and view all the answers

What is the definition of sustainability?

Meeting the needs of the present, without compromising future needs (C) Signup and view all the answers

Which of the following best describes an indicator species?

A species that is very sensitive to specific environmental conditions. (C) Signup and view all the answers

Which indicator species is associated with clean water?

Stonefly larvae (A) Signup and view all the answers

What does the presence of sludge worms indicate about the quality of water in a river?

It may have low oxygen levels. (A) Signup and view all the answers

What is a consequence of climate change on food security?

Disrupted rainfall patterns, impacting crop yields (D) Signup and view all the answers

What is the main cause of water evaporation in the water cycle?

Solar energy (C) Signup and view all the answers

What type of lichen indicates clean air?

Green fluffy lichens (C) Signup and view all the answers

What is the first level of organisation in an ecosystem?

Individual (A) Signup and view all the answers

What negative effect can excessive use of fertilizers have on aquatic ecosystems?

Eutrophication (A) Signup and view all the answers

How is efficiency calculated in energy transfer between trophic levels?

Efficiency = energy transferred to next level / energy available at previous level x 100 (A) Signup and view all the answers

What happens to plants during eutrophication when light is blocked by algae?

They start to die and decompose (C) Signup and view all the answers

Study Notes

Decomposition

Living things are composed of elements.
Decomposition returns these elements to the air and soil after death or waste release.
Bacteria and fungi are the primary decomposers.
Decomposition rate depends on three factors:
- Temperature: Warmer temperatures accelerate enzyme-driven microbial reactions, increasing decay speed.
- Water content: Moist environments promote decay, as microbes need water to function.
- Oxygen availability: Abundant oxygen accelerates decay, as many microbes require it for aerobic respiration.
Food preservation slows decomposition by reducing suitable conditions for microbial survival and reproduction.
- Refrigerating/freezing lowers temperatures to slow/stop microbial reproduction.
- Airtight containers prevent microbial entry and sterilization kills them.
- Drying food removes water, making survival impossible.

Nitrogen Cycle

The atmosphere is ~78% nitrogen gas (N2).
N2 is inert and unusable by plants and animals.
Nitrogen must be converted to nitrates for plant use.
Decomposers break down proteins in dead organisms and waste to return nitrogen to the soil.
Nitrogen fixation converts atmospheric N2 into usable nitrogen compounds in the soil.
Lightning provides the energy to convert N2 to nitrates.
Decomposers break down organic matter releasing ammonia (NH3).
Microorganisms (ammonia to nitrites, then to nitrates) convert ammonia to plant-usable forms.
Nitrogen-fixing bacteria convert atmospheric N2 to ammonia.
Denitrifying bacteria convert nitrates back to atmospheric N2.
Some nitrogen-fixing bacteria reside in soil/roots of legume plants, forming a symbiotic relationship.

Water Cycle

Solar energy evaporates water.
Warm water vapor rises and cools.
Condensation creates clouds.
Precipitation (rain, snow, hail) provides fresh water.
Water flows into bodies of water, repeating the cycle.
Lack of precipitation causes drought.
Desalination produces potable water by removing salts from seawater.
Thermal desalination boils water, separating water vapor from salt.
Reverse osmosis forces water through a membrane, separating it from salts under pressure.

Conservation and Biodiversity

Biodiversity can be maintained and conserved through various methods.
Human activity often reduces biodiversity, but some activities increase it.
Reforestation in deforested areas increases biodiversity by providing habitats.
Careful planning of reforestation efforts maximizes biodiversity by introducing diverse tree species.
Species conservation schemes protect endangered species by:
- Protecting natural habitats.
- Establishing protected areas outside natural habitats (e.g., zoos).
- Captive breeding programs to increase populations.
- Seed banks for preservation of rare species.
Maintaining biodiversity benefits humans by:
- Ensuring food security.
- Preventing damage to food chains.
- Providing future medicines.
- Supporting cultural aspects.
- Fostering ecotourism.

Carbon Cycle

Carbon is a finite element within the Earth.
Photosynthesis is the entry point for atmospheric carbon dioxide into the cycle.
Plants convert carbon to carbohydrates, proteins, and fats.
Animals consume plants and acquire carbon compounds.
Respiration releases carbon dioxide (CO2) from both plants and animals.
Decomposition releases CO2 from dead plants/animals by microorganisms.
Burning of fossil fuels (wood, etc.) also releases CO2 back into the atmosphere.

Investigating Ecosystems

Quadrat sampling measures the proportion of different components in a 1m² area.

Food Security

Increasing population and dietary shifts toward meat and fish negatively impact food security.
There's less energy and biomass at higher trophic levels.
Overfishing and environmental changes (climate change, soil pollution) pose risks to food security.
Sustainability aims to meet current needs without impacting future generations.

Indicator Species

Indicator species (sensitive to environmental changes) show human activity's impact.
Water pollution can be indicated by oxygen-sensitive species (e.g., stonefly larvae, freshwater shrimp).
Air pollution affects lichen types (e.g., clean air: green, fluffy lichens; polluted air: crusty lichens).

Ecosystems

Ecosystems have different organizational levels:
- Individual: a single organism
- Population: all organisms of one species in a habitat

Human Impacts on Biodiversity and Eutrophication

Human activities sometimes negatively impact biodiversity.
Fertilizers leach into water bodies, causing eutrophication.
Eutrophication: excess nitrates from fertilizers cause rapid algae growth, light blockage, plant death, and decomposition.

Food Chain, Tropic Layers, and Energy Transfers

Energy transfer efficiency: = (energy transferred to next level / energy available at previous level) x 100
Biomass transfer efficiency is calculated similarly.
Trophic levels represent feeding positions in the food chain.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the processes of decomposition and the nitrogen cycle. This quiz covers key concepts such as the role of decomposers, factors affecting decomposition, and the significance of nitrogen in the atmosphere. Perfect for students studying ecology and environmental science.