4.7 Ecologicalproblems  (Page 32/2)

Natural sciences

Grade 8

Environment

Module 38

Ecological problems and solutions

Many of the difficulties that are presently being experienced in nature are caused by humans.

The major problems stem from what is known as the HIPPO dilemma.

H - Habitat loss

I – Invader species

P – Pollution

P – Population growth

O - Over-population

Activity 1:

To realise what man’s role in ecological problems is, and to attempt to find solutions

Man is guilty of all five of these indiscretions. We deforest and simply destroy forests because we want to build roads, houses and industries. Just think of the Amazon: there has been a terrific loss of plants that have to contribute to our oxygen supply in the air.

We allow foreign species, especially plants and insects, to invade areas where they have no natural enemies and thus present major dangers for the indigenous species which are easily crowded out by the aggressive foreign species. Prime examples of this problem are the rooikrans trees on the Cape Flats or the black wattle trees along the rivers in the Boland.

Foreign bees are also a threat to our indigenous bees.

Pollution is obviously one of the most serious problems. We pollute the air, the soil and the water with chemicals, oil, plastic, other materials that are not bio-degradable, and also with noise.

All of this is made worse because the population is increasing by the day. (This has already been dealt with in the module on Biodiversity.)

The massive increase in population also causes over-utilization of all natural resources. The resource that is the most limited is naturally WATER.

Prepare a three-minute speech on the following topic: “Man is not part of an ecosystem, and as soon as he becomes involved in an ecosystem, he disturbs the system.”

Activity 2:

The following project focuses on the meaningful utilization of water as one of our most important natural resources

Project: WATER AUDIT AT SCHOOL

Divide into groups of four. Plan the following:

1. how you are going to determine the water consumption at your school;

2. how you are going to present the findings in a report;

3. which possible cases of water wastage you will be investigating;

4. which recommendations you will make.

• Your teacher will fix a date for the submission of the report.
• Each group will present its report to the class.
• A summary of the final findings can be submitted to school management. A class discussion on the recommendations that are to be submitted would be valuable.

• It would be useful to examine the following as part of the research assignment:

1. Wasting water at taps

You can determine the water consumption of the average learner by following these steps:

Divide into groups of four. You will need a large measuring cylinder, a stopwatch and a bucket.

One person in the group is the time-keeper.

Two people drink.

One person notes down the observations in a table.

When the stopwatch starts running, open the tap normally and drink, using your hand as you would normally do. In the bucket, catch up the water that runs off. The time-keeper will tell you to stop after 30 seconds. One person now pours the wasted water into the measuring cylinder and measures how much water has gone to waste. Repeat the procedure for the second person and find an average.