Week 6 · Theme 1 Systems, Unit 1 Interactions of Organisms, Concept 1.3 Changes in Food Webs (B) · 3 lessons
2
Homes lost, reefs in danger
Discovery Education Science P5: Term 1, Unit 1, pp. 85–89
GoalExplain how habitat loss changes populations, and why coral reefs matter.
New words
habitat · the place that gives a living thing food, water, shelter and spacecoral reef · a rocky structure in warm seas built by tiny animals called corals, and a home for many sea animalsclimate · the usual weather of a place over many years
Explanation
A habitat gives a living thing what it needs: food, water, shelter and space. When a habitat is lost or damaged, the population of the living things that depend on it can fall. People can cause habitat loss when they build roads and houses, pollute water or take too many fish. A changing climate can also change a habitat. Imagine tiny floating plants that grow best in cool water. If the sea becomes warmer, there are fewer of them, so the small fish that eat them move away, and the seabirds that hunt the fish lose their food. A coral reef is a home for fish, shrimps, turtles and many more animals. If the water is too warm, corals lose the tiny algae that live in them, turn white, and may die. Then the animals that lived there lose their home.
the sea becomes warmer→tiny floating plants become fewer→small fish move away→seabirds lose their food
Worked examples
Reefs in the Red Sea are real and famous. Many kinds of animals live among the corals. Fish, shrimps, an octopus and a turtle are shown here, and all of them need the reef for food or shelter.
Cause
What happens
building on wild land
animals lose space, food and shelter
pollution of water
water plants and animals become sick or die
taking too many fish
fewer fish, so less food for the animals that eat them
warmer sea water
corals turn white and may die
Some causes of habitat loss and what they do:
Youssef reads about a bay where the water became too warm. The corals turned white and the small fish left. The fishers in the village then caught fewer fish, so people were affected too.
Class activity
Habitat poster. Choose an animal that lives near you or in Egypt, for example a desert fox, a heron or a coral fish. Draw its habitat and write four things the habitat gives it: food, water, shelter and space. Then draw what would happen if one of them were lost. Tell a grown-up one way people can protect that habitat.
Practice
1
Name four things a habitat gives a living thing.
Food, water, shelter and space.
2
Name two things that can cause habitat loss.
Any two: building on wild land, pollution, taking too many fish, a warming climate.
3
The sea warms and the small fish move away. What happens to the seabirds, and why?
sea warms→small fish leave→seabirds: ?
They lose their food, so some must move away and others may die.
4
What happens to a coral when the water is too warm for a long time?
It loses the tiny algae in it, turns white (bleaches) and may die.
