Biology: Food Chains and Biomass Transfer

These flashcards cover key concepts related to food chains, trophic levels, biomass transfer, and ecological efficiency.

What does a food chain show?

It describes the feeding relationships between organisms and the resultant stages of biomass transfer.

How are trophic levels represented?

Trophic levels are represented by numbers, starting from 1.

What is trophic level 1?

Plants and algae which make their own food (through photosynthesis) - called producers.

How do decomposers break down dead matter?

Decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules.

Why is dry mass used for biomass?

Because the wet mass varies as the volume of water in the organism varies.

How do you calculate the efficiency of biomass transfer?

Efficiency = (energy transferred / total energy available) × 100.

What percentage of the biomass from one trophic level is transferred to the level above it?

Approximately 10%.

Why are biomass transfers not 100% efficient?

Energy is lost through egestion, excretion, respiration, and the production of inedible bones and shells.

How does the efficiency of biomass transfers affect the number of trophic levels?

The less efficient the transfers, the fewer trophic levels and fewer organisms in higher trophic levels.

What is a biomass pyramid?

A pyramid that shows the total dry mass of organisms at each trophic level.

Where is trophic level 1 located in a biomass pyramid?

Trophic level 1 is at the bottom of the pyramid.

What is a pyramid of numbers?

A pyramid of numbers shows the number of organisms at each trophic level.

Why is a pyramid of numbers not pyramid shaped?

Pyramids of numbers don’t take size and mass of organisms into account.

How do you calculate the efficiency of biomass transfer from flowers to a caterpillar?

Efficiency = (energy transferred / total energy available) × 100.

What is the total energy available in the example from flowers to the caterpillar?

Total energy available = 800 kJ + 4000 kJ = 4800 kJ.

What is the energy transferred from the flowers to the caterpillar?

The energy transferred is 800 kJ.

What is the percentage efficiency of the biomass transfer in the example from flowers to caterpillar?

The efficiency is 16.67%.

What role do producers play in the ecosystem?

Producers make their own food through photosynthesis.

What organisms are found at trophic level 2?

Primary consumers that eat the producers.

What organisms are typically found at trophic level 3?

Secondary consumers that eat primary consumers.

What organisms are found at trophic level 4?

Tertiary consumers that eat secondary consumers.

What is the primary function of decomposers?

To break down dead organic matter and recycle nutrients back into the ecosystem.

How is biomagnification related to biomass transfer?

Higher trophic levels accumulate more toxins due to less efficient biomass transfers.

What is meant by egestion in biomass transfer?

The removal of undigested food from the organism's body.

What role does respiration play in energy loss?

Respiration releases energy and results in loss of carbon dioxide and water.

What happens to energy that is not transferred to the next trophic level?

It is lost as heat, used in metabolic processes, or expelled as waste.

Why might a food chain have fewer trophic levels in a less efficient ecosystem?

Fewer trophic levels result from energy loss at each transfer, limiting higher-level consumers.

What does a biomass pyramid illustrate about the energy available at each trophic level?

It illustrates that less energy is available as you move up each level.

Why are some organisms included in higher trophic levels considered apex predators?

They have no natural predators in their ecosystem.

What factors can affect the efficiency of biomass transfer in an ecosystem?

Factors include food availability, metabolism rates, and environmental conditions.

Why is it important to study biomass transfer?

To understand energy flow and nutrient cycling in ecosystems.

What is an example of a primary consumer?

Herbivores that consume producers like plants.

What is the significance of having a balanced ecosystem?

It ensures stability and sustainability of food chains and biomass transfers.

How do ecosystems recover from disruption?

Through the re-establishment of food chains and biomass balance.

What does the term 'biomass' refer to?

The total mass of organisms in a specific area or volume.

What are microorganisms, and why are they important in ecosystems?

They are small organisms that decompose dead matter and recycle nutrients.

How does pollution impact biomass transfer?

Pollution can introduce toxins that disrupt food chains and reduce overall biomass efficiency.

What role does sunlight play in food chains?

Sunlight is the primary energy source for photosynthesis in producers.

How do trophic levels reflect energy availability?

Each level reflects a decreased amount of energy available for consumers.