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Define a producer.
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All Flashcards in Topic 2.4
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2.4.150 cards
Define a producer.
A producer is an organism that makes its own organic food from inorganic substances using an energy source, usually sunlight.
Makes own food
Define decomposers.
Decomposers break down dead organic matter and waste, releasing mineral nutrients back into the environment.
Break down dead matter
Outline the difference between herbivores, carnivores and omnivores.
Herbivores eat producers, carnivores eat animals, and omnivores eat both producers and animals.
Plant, animal, both
Define a producer.
A producer is an organism that makes its own organic food from inorganic substances using an energy source, usually sunlight.
Makes own food
Define decomposers.
Decomposers break down dead organic matter and waste, releasing mineral nutrients back into the environment.
Break down dead matter
State the main entry point of energy into most ecosystems.
Sunlight captured by producers through photosynthesis.
Sun → producers
Define a food chain.
A food chain is a linear sequence showing how energy is transferred from one organism to another through feeding.
Linear energy transfer
Define a food chain.
A food chain is a linear sequence showing how energy is transferred from one organism to another through feeding.
Linear energy transfer
Outline the difference between herbivores, carnivores and omnivores.
Herbivores eat producers, carnivores eat animals, and omnivores eat both producers and animals.
Plant, animal, both
State the main entry point of energy into most ecosystems.
Sunlight captured by producers through photosynthesis.
Sun → producers
Define biomass.
Biomass is the mass of living material in organisms (energy stored in organic matter).
Living material
Define trophic level.
A trophic level is the feeding position an organism occupies in a food chain.
Feeding position
Define a scavenger.
A scavenger is a consumer that feeds on dead animals and helps begin nutrient recycling.
Eats carcasses
Explain why nutrients cycle but energy does not.
Nutrients are reused when decomposers release them for producers, but energy is dissipated as heat at each transfer and cannot be recycled.
Nutrients reused, energy lost as heat
Define a consumer.
A consumer is an organism that gains energy and nutrients by feeding on other organisms.
Eats other organisms
Define a consumer.
A consumer is an organism that gains energy and nutrients by feeding on other organisms.
Eats other organisms
Define a scavenger.
A scavenger is a consumer that feeds on dead animals and helps begin nutrient recycling.
Eats carcasses
Define trophic level.
A trophic level is the feeding position an organism occupies in a food chain.
Feeding position
Explain why nutrients cycle but energy does not.
Nutrients are reused when decomposers release them for producers, but energy is dissipated as heat at each transfer and cannot be recycled.
Nutrients reused, energy lost as heat
Define biomass.
Biomass is the mass of living material in organisms (energy stored in organic matter).
Living material
State the process that allows producers to trap energy.
Photosynthesis converts light energy into chemical energy stored in glucose (biomass).
Light → chemical
Explain how detritivores and saprotrophs support nutrient cycling.
Both break down dead organic matter; detritivores digest inside the body, while saprotrophs digest outside using enzymes and then absorb nutrients.
Both recycle nutrients
Explain how detritivores and saprotrophs support nutrient cycling.
Both break down dead organic matter; detritivores digest inside the body, while saprotrophs digest outside using enzymes and then absorb nutrients.
Both recycle nutrients
Define mineral nutrients.
Mineral nutrients are inorganic nutrients such as nitrates and phosphates that plants can absorb to build biomass.
Inorganic plant-available
In the chain grass → rabbit → fox, state the trophic level of the rabbit.
Trophic level 2 (primary consumer).
Herbivore = TL2
Distinguish between a detritivore and a saprotroph.
Detritivores ingest dead material and digest it inside the body; saprotrophs digest outside the body using enzymes and then absorb nutrients.
Inside vs outside digestion
Define mineral nutrients.
Mineral nutrients are inorganic nutrients such as nitrates and phosphates that plants can absorb to build biomass.
Inorganic plant-available
In the chain grass → rabbit → fox, state the trophic level of the rabbit.
Trophic level 2 (primary consumer).
Herbivore = TL2
State the process that allows producers to trap energy.
Photosynthesis converts light energy into chemical energy stored in glucose (biomass).
Light → chemical
Distinguish between a detritivore and a saprotroph.
Detritivores ingest dead material and digest it inside the body; saprotrophs digest outside the body using enzymes and then absorb nutrients.
Inside vs outside digestion
In a food chain, what do the arrows represent?
The arrows show the direction of energy flow, from the organism eaten to the organism that eats it.
Food → eater
Identify the consumer type: a vulture feeding on a dead zebra.
Scavenger.
Dead animal eater
State two points that often gain marks in decomposition questions.
Energy flows one-way through food chains, and nutrients are recycled when decomposers release them back to soil or water for producers.
Energy flow + nutrient cycling
Explain why energy flow in a food chain is one-way.
Energy enters as sunlight, is transformed into biomass, and is lost as heat at each transfer, so it cannot be recycled back down the chain.
Heat loss each step
In food chains, arrows point from what to what?
From the food source to the consumer (direction of energy flow).
Food → eater
Identify the consumer type: a vulture feeding on a dead zebra.
Scavenger.
Dead animal eater
In food chains, arrows point from what to what?
From the food source to the consumer (direction of energy flow).
Food → eater
Explain why energy flow in a food chain is one-way.
Energy enters as sunlight, is transformed into biomass, and is lost as heat at each transfer, so it cannot be recycled back down the chain.
Heat loss each step
State two points that often gain marks in decomposition questions.
Energy flows one-way through food chains, and nutrients are recycled when decomposers release them back to soil or water for producers.
Energy flow + nutrient cycling
In a food chain, what do the arrows represent?
The arrows show the direction of energy flow, from the organism eaten to the organism that eats it.
Food → eater
Explain why producers are essential in ecosystems.
They are the main entry point of energy into ecosystems and form the base of food chains and food webs.
Base of energy supply
Explain why decomposers are essential for ecosystem productivity.
They prevent dead matter build-up and recycle nutrients so producers can grow and make new biomass.
Recycle nutrients for plants
State the correct order of trophic levels from base to top.
Producers (TL1) → primary consumers (TL2) → secondary consumers (TL3) → tertiary consumers/top predators (TL4+).
TL1 to TL4+
Explain why producers are essential in ecosystems.
They are the main entry point of energy into ecosystems and form the base of food chains and food webs.
Base of energy supply
State two roles of consumers in ecosystems.
Consumers transfer energy through food chains and help control population sizes; many also recycle nutrients by feeding on dead matter and waste.
Energy transfer + control/recycle
State the correct order of trophic levels from base to top.
Producers (TL1) → primary consumers (TL2) → secondary consumers (TL3) → tertiary consumers/top predators (TL4+).
TL1 to TL4+
Explain why decomposers are essential for ecosystem productivity.
They prevent dead matter build-up and recycle nutrients so producers can grow and make new biomass.
Recycle nutrients for plants
State what is meant by trophic level 2.
Trophic level 2 is the primary consumer level (herbivores that feed on producers).
Herbivores
State two roles of consumers in ecosystems.
Consumers transfer energy through food chains and help control population sizes; many also recycle nutrients by feeding on dead matter and waste.
Energy transfer + control/recycle
State what is meant by trophic level 2.
Trophic level 2 is the primary consumer level (herbivores that feed on producers).
Herbivores
2.4.230 cards
State what is meant by a food web.
A food web is a network of interconnected food chains.
Interconnected chains
Explain why food chains rarely exceed 4–5 trophic levels.
Energy transfer is inefficient; much energy is lost as heat and waste at each step, leaving too little to support many higher levels.
Heat + waste
State what is meant by a food web.
A food web is a network of interconnected food chains.
Interconnected chains
Define a food web.
A food web is a network of interconnected food chains showing multiple feeding relationships in an ecosystem.
Interconnected food chains
Explain why food chains rarely exceed 4–5 trophic levels.
Energy transfer is inefficient; much energy is lost as heat and waste at each step, leaving too little to support many higher levels.
Heat + waste
Define a food web.
A food web is a network of interconnected food chains showing multiple feeding relationships in an ecosystem.
Interconnected food chains
Outline how multiple feeding links can increase resilience.
Alternative feeding pathways allow organisms to switch prey if one species declines, helping maintain energy flow.
Alternative pathways
Outline how multiple feeding links can increase resilience.
Alternative feeding pathways allow organisms to switch prey if one species declines, helping maintain energy flow.
Alternative pathways
Explain why food webs represent ecosystems more realistically than food chains.
Most organisms feed on more than one species and have multiple predators, so energy can move through several pathways.
Multiple pathways
Describe the trend in available energy at higher trophic levels.
Available energy decreases at each trophic transfer, so higher trophic levels have less energy and biomass.
Decreases with level
Describe the trend in available energy at higher trophic levels.
Available energy decreases at each trophic transfer, so higher trophic levels have less energy and biomass.
Decreases with level
Explain why food webs represent ecosystems more realistically than food chains.
Most organisms feed on more than one species and have multiple predators, so energy can move through several pathways.
Multiple pathways
Explain why top predators usually have small populations.
There is less energy and biomass available at higher trophic levels, so fewer large consumers can be supported and they often require large territories.
Less energy supports fewer
Outline one way a complex food web can increase resilience.
If one prey species declines, consumers may switch to alternative prey, allowing energy flow to continue.
Alternative prey
Explain why food chains are short.
Energy decreases at each trophic transfer due to inefficient transfer and heat loss, limiting the number of levels.
Energy loss
Outline one way a complex food web can increase resilience.
If one prey species declines, consumers may switch to alternative prey, allowing energy flow to continue.
Alternative prey
Explain why food chains are short.
Energy decreases at each trophic transfer due to inefficient transfer and heat loss, limiting the number of levels.
Energy loss
Explain why top predators usually have small populations.
There is less energy and biomass available at higher trophic levels, so fewer large consumers can be supported and they often require large territories.
Less energy supports fewer
State two markworthy points to explain short food chain length.
Energy transfers are inefficient with heat loss, and less energy/biomass is available at higher trophic levels to support additional levels.
Heat loss + less available
State two markworthy points to explain short food chain length.
Energy transfers are inefficient with heat loss, and less energy/biomass is available at higher trophic levels to support additional levels.
Heat loss + less available
In a food web diagram, what do arrows represent?
Arrows represent the direction of energy flow from the organism eaten to the consumer.
Food → eater
In a food web diagram, what do arrows represent?
Arrows represent the direction of energy flow from the organism eaten to the consumer.
Food → eater
In food webs, arrows represent what?
The direction of energy flow from the organism eaten to the consumer.
Food → eater
In food webs, arrows represent what?
The direction of energy flow from the organism eaten to the consumer.
Food → eater
Describe the general pattern in biomass and numbers up a food chain.
Biomass and numbers generally decrease at higher trophic levels because less energy is available to build new biomass.
Less at the top
State a typical maximum length of many food chains.
Often 4 to 5 trophic levels from producers to top predators.
4–5 levels
State one limitation of food webs as models.
Food webs may not show population sizes, strength of interactions, or seasonal changes, so they simplify real ecosystems.
Simplified model
Describe the general pattern in biomass and numbers up a food chain.
Biomass and numbers generally decrease at higher trophic levels because less energy is available to build new biomass.
Less at the top
State a typical maximum length of many food chains.
Often 4 to 5 trophic levels from producers to top predators.
4–5 levels
State one limitation of food webs as models.
Food webs may not show population sizes, strength of interactions, or seasonal changes, so they simplify real ecosystems.
Simplified model
Topic 2.4 study notes
Full notes & explanations for Food chains & webs and trophic levels
ESS exam skills
Paper structures, command terms & tips
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