What would happen if all the plants on the planet died?
Why does a predator have to hunt and kill - can't it just eat grass?
Food and feeding in plants and animals
Introducing this topic
Read the following story to the class.
Discuss how the different animals thought another kind of animal would be more important.
Discuss who or what they think is more important in the world.
Let's read the following story together.
Who is the most important?
Some animals stood on the soft green grass around the waterhole one day, admiring the fine job that the maker had done!
The tortoise, slowly and carefully said: "Of all creation I think I like the flamingos the best! Their beautiful pink and white feathers, their graceful necks and long legs - they're just amazing! They are so beautiful maybe they're the most important."
Warthog just harrumphed and rolled in the squishy brown mud munching on some roots.
"Those flamingos are far too delicate!" said the springbok "Look at that strong, fearsome buffalo - no one ever messes with him! His horns are so sharp he can pierce a rock! I think he is the most important in all creation!"
Warthog just harrumphed and sat on the cool green grass taking a huge tasty mouthful.
The baboon jumped from his perch in a nearby tree "Hahaha-ing" and "KwahKwahKwah-ing" as he went. "You are all so wrong! Look at the eagle - she soars over everyone and can see everything. She is always safe high in the cliffs and never has to come to this messy old waterhole. She doesn't need us - she is the most important of everyone!"
Warthog just harrumphed and scratched his back against the rough hard bark of a baobab.
The dungbeetle clambered on top of his ball, rested his head on his hand and said: "You have no idea - the ants, now they're an important bunch! Without those little fellows the entire world would be covered in dead stuff! The smell would be un-be-lie-va-ble! They are the most important by far!"
Warthog harrumphed, really loudly this time. "Without plants we'd all be gone!" and with that he shoved a clump of reeds and munched at the little insects escaping.
After reading the story ask learners why the warthog said "Without plants we'd all be gone"? Discuss the different things we get from plants - use this opportunity to assess their existing knowledge about plants and photosynthesis.
Do you think plants get hungry? If they do not have mouths, how do they eat?
PLants do not EAT in the same way humans do. They make their own food inside their little "factories". They do this through a process called photosynthesis:
They absorb water and nutrients through their roots.
The water travels to the leaf or stem where the plants make the food
The plants also carbon dioxide (a gas) from the air.
They also use energy from the sun (which they get from the sunlight) for this process
The plants use the water and carbon dioxide gas with the sunlight energy to make food in the form of sugars.
Oxygen (a gas) is given off as a by-product of this process.
The plant can then use the food (sugars) that it produced to carry out its own life processes.
Plants generally make much more food than they need to live. They store the extra food that they make in different parts of the plant.
Animals then eat these parts of the plant (or the whole plant).
Plants make their own food through the process of photosynthesis.
Why do animals need the food that plants make? Discuss this with a friend and report back to the class.
Animals need the food that plants make to carry out the life processes. If they do not have the food or oxygen they will die. Facilitate this discussion to reach a conclusion that without plants animals will not be able to live.
Now we know that the warthog was right: "Without plants we would all be gone!" We would not have food to eat and we would not have oxygen to breathe.
What would you be prepared to pay for a day's worth of oxygen? Plants make this all for free for us!
At the beginning of this term you learnt that animals and plants are interdependent - that means they depend on each other to survive. All living plants and animals need food to give them energy in order to survive.
Plants make their own food through photosynthesis. Living things that can make their own food are called producers because they produce their own food.
Turn to a friend. Take turns to explain what "ingredients" a plant uses during the process of photosynthesis and what the plants make or produce from this. Write your answer below.
A plant uses sunlight energy, water and carbon dioxide during photosynthesis and makes food (sugars) and oxygen.
Animals can't use sunlight, water and carbon dioxide to make food like plants do. Animals need to eat plants (or other animals) for energy to carry out their life processes. Living things that get their energy by eating either a plant or an animals are called consumers.
Hand out little pieces of paper (Post-it notes work well) and get learners to write their favourite animal on it. On the board make three columns and write as heading on each: (Plant-eaters or Herbivores) → (Meat-eaters or Carnivores) → (Omnivores). Ask learners to think about their animal and what they would eat. Let learners paste their post-its or little papers with prestik in the correct column. Discuss the adaptations, similarities and differences between groups with the class.
Many animals get their energy from eating plants. We call these animals herbivores.
Some animals eat other animals to get energy. We call these animals carnivores.
Other animals can eat plants and animals, like baboons or people. We call these animals omnivores.
We get special animals called scavengers and decomposers. They eat dead animals and break their bodies into tiny tiny pieces that can go into the soil as compost. These pieces must be small enough for plants to absorb.
PREPARATION: Collect and display as many books and reading material related to animals as possible and where possible display information specific to the animals in the activity.
Identifying herbivores, omnivores, carnivores, scavengers and decomposers
MATERIALS:
Books and reading material on all sorts of animals displayed in class.
Do research in your local library or on the Internet and bring information on one of the animals in the picture below to class.
INSTRUCTIONS:
Identify the different animals in the picture below. Sit with a friend in class and see if you can name as many of the animals as possible.
Identify what the animals eat.
Classify the animals as a herbivore, omnivore, carnivore, scavenger or decomposer.
Select 3 of each and record them in the table below.
Name of animal
Food that it eats
3carnivores are:
3herbivores are:
3omnivores are:
3scavengers are:
3decomposers are:
Answers:
Name of animal
Food that it eats
3carnivores are:
crocodile
Animals that come to drink at the water
dolphin
fish
mosquito
warm blooded animals
shark
fish, seals, penguins, etc.
lion
animals
leopard
animals
eagle
rodents, rabbits, snakes, fish, etc.
seal
fish, crabs, snails, etc
3herbivores are:
elephant
leaves, fruit off trees
horse
buffalo
springbok
grasshopper
squirrel (some squirrels have been known to eat small insects, birds, etc when food is very scarce)
zebra
rhino
cow
3omnivores are:
pig
cockroach
flamingo
filter feeders - small plant and animal material
3scavengers are:
fox
vulture
crab
3decomposers are:
earthworm
fly
snail
Food chains
Introducing this topic
Ask the question: So if ALL animals depend on plants for food what about an animal that NEVER eats plants - like a crocodile or a lion, or a shark perhaps? Do they depend on plants for food? Discuss this at length without "giving the answer away" to judge their level of understanding of the preceding work.
Discuss predator and prey animals and let learners identify predator and prey relationships and justify their choices by listing adaptations in the predator that allows it to catch its prey. Where possible identify characteristics in prey animals that help them elude predators.
Where do lions or sharks get their energy from? They do not eat plants.
The learners should have a much better idea of how these predators will get their energy hence the questions here. It would be a good point to let them reflect on their own developing knowledge and understanding at this point using this question / answer in preparation for the following work on food chains.
There is a feeding relationship between producers and consumers. We call this relationship a food chain.
Plants are the producers.
Animals are the consumers.
A food chain describes how each living thing gets food and how energy is passed from one organism to the next.
A common misconception is that the sun is part of the food chain. This is incorrect. The Sun is the source of energy, but it is not a source of food for the plant. The Sun is not food for the plant. So the food chain does not start with the Sun, it starts with the PLANT which is the PRODUCER of food. The learners should just know that the Sun is the source of energy (NOT FOOD) otherwise plants will not be able to make their own food. The FOOD CHAIN always starts with the PLANT (PRODUCE OF FOOD). Decomposer are generally also not put in as part of the food chain. Decomposers could go at both ends. Their exact position can't really be pin pointed, since it could go in at any point. The decomposer would supply nourishment to grass. Then that grass would be eaten by a rabbit or some herbivore/omnivore, which might get eaten by a carnivore. But when the carnivore dies, the decomposer would come back into the equation and break down the carnivore, thus giving to the grass or other
vegetation, creating a loop. Also the decomposer could come in at any point should any other link die; the decomposer would just break it down again.
When we draw a food chain we use an arrow ( → )between organisms to show that one eats the other and that energy is transferred from the one organism to the next.
A simple food chain is: grass → cow → human → ‰worms.
Many food chains that are interdependent and linked are called a food web.
A simple food chain. Can you name the herbivores, omnivores, carnivores and decomposers?
Collect as many books and any reading materials about habitats.
Before the next activity, allow the learners to go through these and choose a specific habitat like the savannah, woodlands, aquatic, arctic, etc.
They need to identify all the animals and plants in that specific habitat.
Let them make notes on scrap paper using the headings: PRODUCERS and CONSUMERS
The reason for doing this next activity:
To help learners understand the flow of energy in a food chain.
To help learners see the interdependence of organisms in a food chain. They learnt about interdependence at the start of this term's work and this is a wonderful way to reinforce this knowledge.
(To teach them that food chains are linked and are called food webs.)
Making food chains
MATERIALS:
Your teacher will make a big yellow sun and pin it to the centre of your class' ceiling.
3 different coloured pieces of paper or thin cardboard (Green for plants and two other colours, NOT yellow as the sun is already yellow).
Stapler and staples or cellotape or pins. If you have to use glue, hold the ends together with washing pegs until the glue has dried.
Scrap paper, colouring pencils and/or kokis or cut out pictures of animals and insects
Scissors
Glue
Thumbtacks and/or Prestik
INSTRUCTIONS:
Cut the paper into long strips, 3 cm wide.
Use the colours as follows:
GREEN strips for the producers - the plants.
One colour for the consumers - the animals eating the plants. (You could even have two colours here - one for herbivores and one for carnivores/omnivores)
Design your own food chain in the space below. Remember to start with the producers then add in consumers. To show the flow of energy you must use an arrow ( → ).
Collect cut out pictures of the animals in your food chain or draw your own pictures on scrap paper and cut these out carefully.
Put your chain together as follows:
Start with the green strip for the plants - staple the two ends together to form a link on a chain. Stick your picture of the plant in your food chain on here.
Two links in the chain so far - a green plant and the first consumer (a herbivore).
Use the same amount of "consumer coloured" strips as the amount of consumers in your food chain. Stick the pictures of your consumers in order onto these strips.
A longer chain - remember your chain will have pictures of the plants and animals on each link!
Pin your food chain to the ceiling. It should look like a large spider's web when everyone's chains are up.
When the learners bring their food chains to be put up, it is important that you group similar habitats together. (And that you wear trousers that day!)
Point out that different predators from the same habitat can feed on different prey in other food chains, i.e. the fox that eats the rabbit in one food chain can also catch the chicken, rat or mouse in other chains or eat the dead sheep in another.
Use string / wool to show this interdependency and lead learners to conclude that food webs show the way that food chains are linked.
The organisms that make up a food chain cannot be in any random order. They have to be in the specific order in which the energy is transferred between them in an ecosystem. Let's have a look at re-ordering food chains which are broken.
Sequencing plants and animals in food chains.
INSTRUCTIONS:
The following lists of animals and plants are in the wrong order.
You must sequence them so that they make up a proper food chain in which the energy is transferred from one organism to the next.
Make sure to draw an arrow from one organism to the next to show the direction.
You can even draw some pictures of the animals if you want to.
grasshopper, hawk, snake, grass
grass → grasshopper → snake → hawk
shrimp, seal, fish, algae
algae → shrimp → fish → seal
bee, flower, butcher bird, spider.
flower → bee → spider → butcher bird
mouse, jackal, leopard, grass.
grass → mouse → jackal → leopard
Are humans also part of a food chain?
Most humans are omnivores and like to eat plant and animal products.
What do you call a human herbivore?
Vegetarian
Let's look where humans fit into food chains.
The reason for doing this activity is to apply the knowledge, skills and concepts learnt about food chains. Learners need to do some homework before this activity so make sure to instruct them to do so the day before you want to do this activity. Homework: Make a list of all the things you eat and drink from when you wake up to when you go to sleep at night.
Discovering your place in different food chains
MATERIALS:
Alist of all you ate and drank from when you woke up yesterday morning to when you went to sleep last night.
INSTRUCTIONS:
Order everything you ate and drank in a day into the following categories
Plants I ate were:
Idrank the juice of plants when I drank:
Iate animal products when I ate:
Idrank animal products when I drank:
Iate a combination of animal and plant products when I ate:
QUESTIONS:
Now design a food chain of some of the plant and animal food products that you ate.
Why do you think people say that human beings are "at the top of the food chain"?
Wow, I feel really humbled by our place in the food chain. Although we are "at the top" it also means we have a lot of responsibility to be conscious of what we eat.
Write a Food Chain poem
MATERIALS:
The habitat and animal books on display in your class.
Scrap paper for planning and drafting.
INSTRUCTIONS:
Write a food chain poem.
The heading of your poem must describe or label the type of habitat in which the food chain is located.
The body must explain the flow of energy in the food chain.
The ending must repeat the heading and your name.
Use a thesaurus to get ideas for different verbs instead of only using "EAT"..
Here is an example of a food chain poem written by Farrah:
The Savannah
These are the lion cubs
that were fed by the graceful lioness
that caught the zebra
that munched the grass
that grows on the savannah where Tumi Nxoko lives!
Green plants make their own food to build their branches and stems.
Green plants use water, carbon dioxide and sunlight energy to make food.
Plants are called producers.
Animals need food to grow and carry out the life processes.
Animals cannot make their own food and have to eat plants or other animals for food. Animals are called consumers.
Food chains describe the feeding relationships between plants and animals.
Energy is transferred from the sun to green plants and then to the animals in the food chain.
Read the information and look at the pictures below. Then answer the questions that follow.
Write a five link food chain using the information and pictures above.
lettuce - snail - beetle - rodent - eagle
Which organisms are herbivores?
snail
Which organisms are carnivores?
beetle, rodent and eagle
The energy flow in this food chain started with a main source of energy. What source of energy provided this source of energy?
sun
Explain the interdependence in this food chain?
Each animal depends on the one before it for food. If one of the animals is removed from the ecosystem then the next animal would not have a food source. This animal would suffer and die out, which means the next animal would then also die out. Each animal is dependent on all the other organisms which come before it in the food chain, even if it does not eat it directly.
What would happen if the eagle was removed from this food chain?
There would be nothing eating the rodents. The rodents would then start to flourish and their numbers would increase. This would put a stress on the beetles as there would be more rodents eating the beetles. The beetle population would then start to decrease. The whole ecosystem would become unbalanced.
The eagle grew old and died. Explain how the eagle's body was broken down and became part of the soil. Give examples of animals that helped this process.
Decomposers, such as earthworms and microbes, break down the body of the eagle. The body decomposes and nutrients and minerals are returned to the soil.
Look at the following picture of a food chain. Name the producer, the herbivore and the carnivores.
Producer: grass
Herbivore: grasshopper
Carnivore: mouse and owl
The mouse also eats other plants, such as seeds and nuts. So the mouse is not only a carnivore. What is it?
