1. Producers & Consumers
D. Crowley, 2008

2. Sunday, September 08, 2019Sunday, September 08, 2019
Producers & Consumers
To know how energy is passed from producers to consumers in food chains

3. Food Chains What is a food chain?
A food chain shows the different organisms that live in a habitat, and what eats what
A food chain always starts with a producer, which is an organism that makes food (usually a green plant, because plants can make their own food by photosynthesis)
A food chain ends with a consumer, which is an animal that eats a plant or another animal
grass  cow  human
*The arrow points to the organism that is doing the eating

4. Food Chains
There are some more key words within a food chain – study the following food chain, and try and work out what some of the key food chain words are, and what they mean…

5. Food Chains The plant is the producer and the animals are consumers
The first consumer in the chain is also called the primary consumer, the next one is the secondary consumer and the one after that is the tertiary consumer…
A consumer that eats plants is called a herbivore
A consumer that eats other animals is called a carnivore
An omnivore is an animal that eats plants and other animals.

6. Food Webs
In most habitats organisms normally eat / are eaten by more than one other organism
To represent this we use food webs (like food chains but they interlink with one another, e.g. a pond
Here the producers are the pondweed and the microscopic algae
Dragonfly nymphs and brown trout eat the mayfly nymphs
The brown trout also eats the dragonfly nymph
The freshwater shrimp are eaten by the dragonfly nymph and the brown trout

7. Energy
The arrow shows the energy being transferred from one organism to the next
Between each step energy is lost in a variety of ways, including: -
Growth of the organism
Reproductive costs
Lost through waste products (poo)
Lost through heat
This is why food chains are not infinitely long – energy is lost from one stage to the other

8. Energy
Complete the energy from plants worksheet

9. Energy From Plants
Plants produce food (glucose) which is useable energy for other organisms
Some energy is used up in the plant, such as for respiration / reproduction / growing etc…
6% of the energy is used (60% is lost as waste, and 34% is lost via respiration)
a) 34% of 3000 = 1020 units; b) 60% of 3000 = 1800 units
Energy is lost as the cow how been respiring and used up some of the potential plant energy. Also, not all parts of the cow are eaten!
Growing crops and eating them is much more energy efficient than farming animals as there is less energy wastage

10. Energy Transfer Think of your favourite person in the world...!
E.g. a sports person / actor / musician etc…
Try and explain how they live, in terms of a food chain (diagrams may help)
Sun  grass  cow  human

11. Glucose Plants produce glucose (their food) via photosynthesis
However, they normally sore this glucose as starch (as it is insoluble), e.g. a potato
Why is it that plants store glucose within fruit?!
The fruits contain sugars to encourage animals to eat them (which helps with seed dispersal)

12. Glucose
Complete the glucose worksheet

13. Glucose Photosynthesis Starch is found within the chloroplasts Potato
Plants store starch so they have access to the energy when the need it (it is also insoluble, making it a good storage material)
Cellulose is found within the cell wall
Oils and fats are found in the cell membrane
glucose + oxygen  carbon dioxide + water (+energy)