THE HUMAN POPULATION
The human population is increasing rapidly. This is increasing the use of finite resources such as fossil fuels and minerals. As a result, the amount of waste and pollution is also on the rise. Certain species are endangered - if they are not helped, they are likely to become extinct.
The human population
Like all living things, humans exploit their surroundings for resources. Before the beginning of agriculture about 10,000 years ago, small groups of humans wandered across large areas, hunting and gathering just enough food to stay alive. Population numbers were kept low because of the difficulty of finding food.
The development of agriculture led to a population explosion that has accelerated enormously during the past 500 years. Unlike other species, humans can adapt to and survive in almost all habitats and climates
STANDARDS OF LIVING
Standards of living
People in the developed world enjoy a high standard of living, with abundant food, cars and comfortable housing. People in the developing world have a lower standard of living, but many countries are catching up quickly.
Impact of humans
The world’s human population has passed 6 billion and continues to increase. The growth in the human population and the increase in the standard of living are putting strains on the global environment. Here are some of the ways in which this is happening:
- non-renewable energy resources, such as coal, oil and natural gas, are being used up rapidly
- raw materials are being used up rapidly
- more waste is being produced
- more pollution is being caused
Most rubbish is buried in landfill sites and not all of it comprises safe materials. Even common household items can contain toxic chemicals such as poisonous metals. Many smoke alarms contain radioactive americium. Industrial waste is also discharged onto the land. Many farmers apply pesticides to improve their crops, but these can damage living things. Toxic chemicals can be washed from the land into rivers, lakes and seas.
-Water pollution is caused by the discharge of harmful substances into rivers, lakes and seas.
fertilisers damage to aquatic ecosystems sewage kills aquatic organisms and harms human health toxic chemicals kill aquatic organisms and harm human health
Many aquaticinvertebrateanimals cannot survive in polluted water, so their presence or absence indicates the extent to which a body of water is polluted
The most common source of air pollution is the combustion of fossil fuels. This usually happens in vehicle engines and power stations.
smoke Deposits soot on buildings and trees, causing them damage. Permeates the air, making it difficult for living creatures to breathe. carbon monoxide poisonous gas carbon dioxide greenhouse gas that contributes to global warming sulfur dioxide contributes to acid rain CFCs depletes ozone in the upper atmosphere, so damages the ozone layer
INDICATORS OF AIR POLLUTION
Lichens are plants that grow in exposed places such as rocks or tree bark. They need to be very good at absorbing water and nutrients to grow there, and rainwater contains just enough nutrients to keep them alive. Air pollutants dissolved in rainwater, especially sulfur dioxide, can damage lichens, and prevent them from growing. This makes lichens natural indicators of air pollution. For example:
- bushy lichens need really clean air
- leafy lichens can survive a small amount of air pollution
- crusty lichens can survive in more polluted air
In places where no lichens are growing, it's often a sign that the air is heavily polluted with sulfur dioxide.
Individuals that are poorly adapted to their environment are less likely to survive and reproduce than those that are well adapted. Similarly, it is possible that a species that is poorly adapted to its environment will not survive and will become extinct.
Here are some of the factors that can cause a species to become extinct:
- changes to the environment, such as a change in climate
- new diseases
- new predators
- new competitors
The fossil record shows that many species have become extinct since life on Earth began. Extinction is still happening and a lot of it occurs because of human activities. We compete with other living things for space, food and water, and we are very successful predators.
HELPING ENDANGERED SPECIES
The panda and gorilla are endangered, and may become extinct. Some species in Britain are endangered, too, including the red kite, red squirrel and osprey. They could be helped by measures such as:
- education programmes
- captive breeding programmes
- legal protection and protection of their habitats
- making artificial ecosystems for them to live in
These measures are difficult to implement when dealing with certain organisms, such as whales. These animals live in international waters, so international laws and agreements are needed to protect them.
Sustainable development means improving our quality of life without damaging the quality of life of future generations. It is important to all of us, not just the other inhabitants of the planet, that sustainable development is achieved. This involves each of us as individuals, and careful planning at local, regional and global levels.