Grade 7 Term 4 Flashcards
What is one of the spin-offs from nature conservation?
Ecotourism. It brings visitors to South Africa and helps provide jobs for many people.
Define the term “natural resources”.
Natural means Occurring in nature, and a resource is something that can be used to survive and make a living.
Give five facts about air as a resource.
It is an inexhaustible resource.
It is essential to the survival of of all living organisms on Earth.
It is made up of 78% Nitrogen and 21% oxygen. The other 1% consists of traces of water vapour, carbon dioxide, argon and a few other components.
In the atmosphere, 95% of the total air is present up to a height of 20 km above the Earths surface and the remaining 5% is present up to a height of about 280km.
Industries are responsible for a lot of air pollution and breathing polluted air may cause respiratory problems, headaches, sleepiness and even lung cancer.
Which industries are the big air polluters?
Chemical manufacturers, iron and steel plants, cement manufacturers, thermal electric power stations, coal- fired electricity plants.
Name other sources of air pollution.
Cars, fires, burning rubbish, accidents involving chemical transport etc. etc.
What is the water cycle? Describe the key elements of this cycle.
It is the constant movement of water from the the land into the air and back again. The sun provides the energy which causes the water on the surface of the Earth to evaporate. The liquid water turns to water vapour. This in turn condenses and forms small droplets in the clouds. Water in the form of dew, rain, sleet or snow returns to the Earth. This is called precipitation. The water that falls on the Earth either soaks into the ground or flows back into rivers and dams and the oceans as run-off.
Where do you find 97% of the water on Earth?
In the oceans.
With droughts etc., why can’t we just use the water in the oceans?
The salt has to be removed and desalination is an expensive method of doing this.
Where is 2 thirds of the fresh water found on Earth?
In glaciers and ice caps.
True or false: there is more fresh water beneath the surface of the earth than above the surface in dams and rivers.
True.
Give an explanation of how water gets polluted.
When too much water is used to irrigate crops, fertilizers and pesticides can be washed into rivers. This pollutes the river water and poisons fish and plants downstream.
Other forms of water pollution comes from human waste and harmful chemicals polluting rivers and dams. This can lead to the rapid growth of algae and water hyacinth which uses up oxygen in the water. Without enough oxygen, the fish can die.
For five marks, What are the most important and useful natural resources and why are they important?
Trees.
A forest protects the soil from soil erosion during a heavy rain storm.
It’s also home to thousands of birds, insects and other animals.
People enjoy the peace of a forest.
A forest provides food for the people living near it.
Many natural medicines come from trees.
Forests act as the lungs of the world by producing oxygen.
When trees are cut down, the wood is used in many ways: paper, firewood, furniture, building industry.
What is environmental conservation?
It is the protection of the environment and its inhabitants and the wise use of natural resources for the benefit of future generations.
Why should we conserve the environment?
To ensure and preserve our quality of life.
All animals are part of the natural environment and its wrong to destroy or abuse any part of the environment. When plants and animals become extinct they can never be replaced.
Nature provides a living for people.
Scientific research is constantly discovering new uses for plants, especially in medicine. A cure for major diseases may be lost forever if certain plant species disappear.
How can we conserve our environment? (5 marks)
Educating the population Protecting endangered species Relocating game to safe areas Establishing breeding programmers for endangered animals Establishing and enlarging game parks.
