Food Chains
and Food
Webs
“A learned society advancing marine
science through research,
communication and education”
Life Around the Turbines resources are free and can be downloaded from www.mba.ac.uk/education
What do all living things have in
common?
o We all need energy to live and grow.
o Plants and algae get energy from the
sun.
o Animals get energy from food.
www.mba.ac.uk/education
The plants and animals living
in a habitat are linked
together by their feeding
relationships.
o In most habitats there are:
– Producers which are mainly plants or algae.
– Consumers which are animals.
www.mba.ac.uk/education
Producers
o Plants and algae are called producers because
they produce their own food using sunlight, water
and nutrients in a process called photosynthesis.
www.mba.ac.uk/education
Producers in the sea
• On land, producers are green plants
like trees, shrubs and grass.
• In the sea, producers are seaweeds,
sea-grasses and phytoplankton.
• Phytoplankton are microscopic algae
which float in the water and are eaten
by many different animals.
Phytoplankton
www.mba.ac.uk/education
Consumers
Animals are called consumers because
they consume (eat) food provided by
plants or other animals.
Image: Mmo iwdg
Image: John Haslam
Image: Norman Jackson
www.mba.ac.uk/education
Think of some examples of producers
and consumers
o What does the consumer that you
chose eat?
o Plants?
• If it only eats plants it is called a
herbivore or a primary consumer
o Animals?
• If it only eats other animals it is
called a carnivore or a secondary
consumer
o Or both?
• If it eats both plants and animals
it is called an omnivore
www.mba.ac.uk/education
Predators and prey
A predator is an animal which hunts and
eats other animals for food (its prey)
www.mba.ac.uk/education
Can you think of representatives
for each of these groups?
o
o
o
o
o
o
o
Producer
Consumer
Herbivore
Carnivore
Omnivore
Predator
Prey
www.mba.ac.uk/education
Food chains
o The sequence of steps in a feeding
relationship is called a food chain.
o A food chain is made up of producers
and consumers, and always starts
with a producer.
o Energy is transferred up the food
chain from plants to animals.
www.mba.ac.uk/education
The transfer of energy in a
simple food chain
Energy
• SECONDARY CONSUMER (Carnivore)
Energy
• PRIMARY CONSUMER (Herbivore)
• PRODUCER (Plant)
Can you think of
examples for each
step?
www.mba.ac.uk/education
Can you construct a marine food
chain?
Lets look at a marine food chain, with some of
the species we might find around an
offshore wind farm.
Image: Ashley Dace
Image: Kim Hansen
www.mba.ac.uk/education
Can you make a food chain with
some of these species?
www.mba.ac.uk/education
Here is a simple food chain…
Secondary consumer: starfish
Primary consumer: mussel
Producer: phytoplankton
www.mba.ac.uk/education
And another one:
Secondary consumer: herring gull
Primary consumer: harbour crab
Producer: seaweed
www.mba.ac.uk/education
If each predator only ate one particular
prey, food chains would always be
simple
But in reality most animals eat a varied diet and
predator-prey relationships are more complex.
– If an animal relied on one food source, what
do you think would happen if that source
disappeared?
www.mba.ac.uk/education
Food webs
o When we look at the feeding
relationships between many different
plants and animals, we don’t just see a
chain.
o Each species might be prey for several
different predators, and each predator
will eat several types of prey.
o So we see a food web.
www.mba.ac.uk/education
Now Make Your Own Food Web
www.mba.ac.uk/education
A very simple food web...
www.mba.ac.uk/education
Here is a more detailed food web...
Grey seal
www.mba.ac.uk/education
Food webs are very complex!
o Now try to draw your own marine
food web including some of the plants
and animals found around an offshore
wind farm.
o Can you think of a simple food web
which includes some of the things you
eat?
www.mba.ac.uk/education
What have we learned today?
o All living things in a habitat are linked
together by predator-prey relationships.
o Producers (plants) make food for consumers
(animals) to eat.
o Consumers can be herbivores, carnivores or
omnivores.
o A food chain is made up of producers and
consumers.
o Energy is transferred up this chain from
plants to animals.
o In reality, many food chains exist as
complicated food webs.
www.mba.ac.uk/education
www.mba.ac.uk/education