2.2-2.3 Communites and Ecosystem

Question 1

Respiration

Answer 1

The process where organisms convert glucose and oxygen into energy (ATP), releasing carbon dioxide and water.

Question 2

Photosynthesis

Answer 2

The process where plants convert sunlight, carbon dioxide, and water into glucose and oxygen.

Question 3

Chemosynthesis

Answer 3

The production of organic compounds using energy from chemical reactions instead of sunlight, typically in deep-sea ecosystems.

Question 4

Food web

Answer 4

A complex network of interconnected food chains showing energy flow in an ecosystem.

Question 5

Ecological
pyramid

Answer 5

A graphical representation of relationships between trophic levels

Question 6

Biomass

Answer 6

The total mass of living organisms in a given area or trophic level, usually measured as dry weight per unit area (e.g., g/m²).

Question 7

Examples of consumers

Answer 7

Organisms that obtain energy by eating other organisms. Examples:
Primary consumers (herbivores) – deer, rabbits.
Secondary consumers (carnivores/omnivores) – foxes, frogs.
Tertiary consumers (top predators) – eagles, sharks.

Question 8

Trophic Levels

Answer 8

The hierarchical levels in a food chain/web based on energy transfer. Example: Producers → Primary Consumers → Secondary Consumers → Tertiary Consumers.

Question 9

Primary productivity

Answer 9

The rate at which producers convert solar or chemical energy into organic substances.

Question 10

Secondary productivity

Answer 10

The rate at which consumers convert ingested food into biomass

Question 11

Sustainble yield

Answer 11

The rate at which a natural resource (e.g., fish, timber) can be harvested without depleting the stock, ensuring long-term availability.

Question 12

Ecological Efficiency

Answer 12

Ecological Efficiency=(energy used for growth(new biomass)/energy suplied)x100

Question 13

Nitrogen Cycle

Answer 13

The biogeochemical cycle where nitrogen is converted between different forms (e.g., nitrogen fixation, nitrification, denitrification) to support life.

Question 14

Carbon Cycle

Answer 14

The movement of carbon through the biosphere, atmosphere, oceans, and geosphere, involving processes like respiration, photosynthesis, combustion, and decomposition.

Question 15

Pyramid of biomass

Answer 15

A diagram showing the total biomass at each trophic level in an ecosystem.

Question 16

Pyramid of Productivity

Answer 16

A diagram showing the energy flow and loss at each trophic level over time, typically measured in kJ/m²/year.

Question 17

Carbon Cycle Process

Answer 17

1️⃣ Main Carbon Stores: Atmosphere, oceans, fossil fuels, soil, and living organisms.
2️⃣ Key Processes: Photosynthesis (absorbs CO₂), respiration (releases CO₂), combustion (burning fossil fuels), decomposition (releases CO₂).
3️⃣ Human Impact: Deforestation and burning fossil fuels increase atmospheric CO₂, contributing to climate change.

Question 18

Nitrogen Cycle Process

Answer 18

1️⃣ Main Nitrogen Stores: Atmosphere (78% nitrogen gas), soil, water, living organisms.
2️⃣ Key Processes:

Nitrogen Fixation: Bacteria convert N₂ into ammonia (NH₃) or nitrate (NO₃⁻) for plants.
Nitrification: Ammonia is converted into nitrites (NO₂⁻) and then nitrates (NO₃⁻).
Assimilation: Plants absorb nitrates to make proteins.
Denitrification: Bacteria convert nitrates back into nitrogen gas (N₂), releasing it into the atmosphere.
3️⃣ Human Impact: Excessive fertilizer use leads to eutrophication (algal blooms that deplete oxygen in water).

Question 19

Stores

Answer 19

A place where matter or energy is accumulated and held for a period of time. Example: The ocean is a major carbon store.

Question 20

Sink

Answer 20

A store that absorbs more of a substance than it releases. Example: Forests act as a carbon sink by absorbing CO₂ through photosynthesis.

Question 21

Source

Answer 21

A process or area that releases more of a substance than it absorbs. Example: Burning fossil fuels is a carbon source, releasing CO₂ into the atmosphere.