الأسبوع 4 · المحور الأول «الأنظمة»، الوحدة الأولى «العلاقات الغذائية بين الكائنات الحية»، المفهوم 1.2 «انتقال الطاقة في النظام البيئي» (ب): السلاسل والشبكات الغذائية · 3 دروس
1
Sunshine, plants and the first link
Discovery Education Science P5: Term 1, Unit 1, pp. 50–53
GoalExplain that the Sun is the first source of energy, and tell producers from consumers.
New words
producer · a living thing that makes its own food, such as a plantconsumer · a living thing that gets energy by eating other living thingsenergy source · where energy first comes from
Explanation
Food is energy for our bodies, and the energy in food began as sunlight. Plants catch light in their leaves and use it to make glucose, so plants are producers. Animals cannot make food from sunlight. They are consumers: they must eat. An animal that eats plants is a primary consumer. An animal that eats plant-eaters is a secondary consumer, and one that eats those is a tertiary consumer. In this way, the energy of the Sun passes to every living thing, from the grass to the bird of prey. If there were no Sun and no plants, there would be no food for animals and people.
light from the Sun→producer: a plant→consumer: eats the plant→consumer: eats the plant-eater
Worked examples
In a field near Tanta, wheat grows in the sunshine. A mouse eats the wheat grains, and a snake eats the mouse. The wheat is the producer. The mouse and the snake are consumers.
Here the living things are sorted into producers and consumers.
Hana eats a cheese sandwich. The wheat in the bread is a producer. The cow that gave the milk ate grass, so Hana’s energy came from plants that used sunlight.
Class activity
Lunch detective. Write what you ate at your last meal. For each food, find the producer it came from, such as wheat for bread or tomato plants for tomatoes. Mark each food as plant food or animal food, and for animal foods, write what the animal ate. Draw the Sun at the start of one chain.
Practice
1
What is the first source of energy for living things on Earth?
The Sun.
2
Which pictures show producers? Say the letters.
A and D: the grass and the palm tree make their own food.
3
Why can an animal not be a producer?
An animal cannot make food from sunlight, so it must eat.
4
A hare eats grass. Is the hare a primary or a secondary consumer? Why?
