4.2.1 Trophic Levels & Food Chains Flashcards
What are Trophic Levels used to describe?
Trophic levels are used to describe the feeding relationships between organisms
Energy flows from the sun to, where?
the first trophic level (producers) in the form of light
What do producers convert light energy into?
chemical energy and it flows in this form from one consumer to the next
Eventually, all energy is transferred to, where?
to the environment – energy is passed on from one level to the next with some being used and lost at each stage
What type of process is Energy Flow
Energy flow is a non-cyclical process – once the energy gets to the top of the food chain or web, it is not recycled but ‘lost’ to the environment
(Trophic Levels) Producers
They produce their own organic nutrients usually using energy from sunlight
(Trophic Levels) Primary Consumers
Herbivores - They feed on producers (Plants)
(Trophic Levels) Secondary Consumers
Predators that feed on primary consumers
(Trophic Levels) Tertiary Consumers
Predators that feed on Secondary Consumers
(Trophic Levels) Quaternary Consumers
Predators that feed on Tertiary Consumers
Animals (known as consumers) can be at different, what?
trophic levels within the same food web as they may eat both primary, secondary and/or tertiary consumers
A simple way to illustrate the feeding interactions between the organisms in a community is with a, what?
food chain
Give each step of a food chain
1. Producer: food chains always begin with a producer
What does a food chain show?
A food chain shows the transfer of energy from one organism to the next
What is the source of all energy In a food chain?
light energy from the sun
What do the arrows in a food chain show?
The arrows in a food chain show the transfer of energy from one trophic level of the food chain to the next
Give an example of 5 Levels (with animals) of a food chain
Trophic (Level 1 Producer) : Grass
Trophic (Level 2 Primary Consumer) : Grasshopper
Trophic (Level 3 Secondary Consumer) : Frog
Trophic (Level 4 Tertiary Consumer) : Python
Trophic (Level 5 Quaternary Consumer) : Eagle; Apex Predator
In order for the energy to be passed on, what has to happen?
it has to be consumed (eaten)
not all of the energy grass plants receive goes into, what?
making new cells that can be eaten
Only the energy that is made into new cells remains with, what?
with the organism to be passed on
The majority of the energy an organism receives gets ‘lost’ (or ‘used’) through, what?
1. Making waste products eg (urine) that get removed from the organism
inefficient loss of energy at each trophic level explains, what?
why food chains are rarely more than 5 organisms long
10% of energy available to the organism at the next level to make, what?
New biomass
Exam Tip
This is a complicated concept but by learning the main ways in which energy is lost between trophic levels, you will be able to answer most questions on this topic.
Make sure you read the question carefully and tailor your answer to the specific organism you are being asked about – e.g. plants do not produce urine or faeces so you could not give this as one of the ways in which they use energy that cannot be passed on!
