LIFE ON MAN
MAN’S body is a walking zoo. Just as he is dependent on plants and animals for his food and very existence, so there are other plants and animals which could not exist without him. Your own body can carry quite a rich variety of flora and fauna; there is plenty of life on man. Although you can’t grow mushrooms on your skin, there are other fungi that can’t grow anywhere else. Ringworm, on the scalp, and athlete’s foot, are among the plant parasites that live on human beings. The insects that do the same include head lice, body lice, and fleas, and there is also the scabies mite which burrows under skin to lay its eggs. There are other occasional insect attackers, such as mosquitoes, which make blood-sucking visits. Bees and wasps may sting, and ants may bite. Then there are viruses and micro-organisms that cause colds and such diseases as pneumonia, polio, and dysentery. But not all the parasites on the human body are harmful. None of us could digest our food without the bacteria living in the gut. The internal digestive system is dependent on its flora.
Perhaps you could work out a diagram to illustrate how man’s body is a habitat for other forms of life, and how his waste products and finally his bones and flesh are returned to earth and water to be re-cycled. Part of nature’s network is dependent on him. But he is dependent on nature – and another part of the same diagram could show how he needs nature for his food -vegetable, animal, fish – and how he uses natural products for his home (wood for beams and floors, reeds for thatch), clothes (leather, wool, silk, cotton) and furniture (wood, wool, leather). Nature could function without man, but not man without nature.
THE LIVING HOUSE
A house too can be a perfect menagerie. Wherever possible, human habitations are invaded by flies, bluebottles, spiders, rats, mice, cockroaches, woodworm, dcathwatch beetles, silver fish, bookworms, and other creatures. Older houses have sparrows and house martins in the eaves, and perhaps bats in the roof space. There is also life in the larder. Yeast is alive, and there may well be moulds on bread and fruit. Another plant in older houses in the hated dry rot, a very damaging fungus.
Housewives wage constant warfare on all these invaders. There is plenty of material here for the ardent naturalist, but it is not of a kind we can easily tolerate. But do we need to keep our houses as clean and sterile as hospital wards? Often when spring cleaning we find clusters of ladybirds on window-sills. They do no harm, and they are not in any way dirty. When warmer weather arrives they will disappear and do nothing but good in the garden. Butterflies, too, are often found behind pictures, or in odd comers behind cupboards and other furniture, as they like to hibernate in warm dry places. Too much dusting will disturb them. They should never be touched or moved. They will fly again when they are ready and will then leave by any open window. Spiders’ webs are very interesting to watch – 4i again, they are not dirty. Must they always be swept away? Spiders may be quite useful catching flies.
POLLUTION IN THE HOME
Our homes make quite a large contribution to pollution. Coal burnt on ordinary domestic fires, in open grates, is much the most serious source of atmospheric pollution. If more of us were able to use smokeless fuel, or change to gas or electricity for heating, the problem of smog would be greatly reduced. And housewives use detergents, for washing clothes and dishes. You may wonder what detergent has to do with pollution and wild life, but the fact is detergents and disinfectants don’t just vanish after being used. They go down the drains, and then through sewage plants, and into rivers, and finally into the sea. Somebody, somewhere, on the way along, has to deal with them. Some disinfectants break down to harmless products, but too much kills the bacteria which help to purify sewage. Detergents may pass through the sewage works without being decomposed, and cause great masses of foam in rivers, called ‘detergent swans’. Today most detergents are what are known as ‘soft’ detergents, and they are broken down more easily, but they can still do damage. They contain a lot of phosphate, which is needed in plant nutrition, but too much of it upsets the plant balance in rivers and lakes. It may then cause ‘algal bloom’ – great blankets of scum on top of the water. Sewage is purified and made safe, in most cases, before being discharged into rivers, but it also adds nitrate to the water. Then nitrates and phosphates work together to cause over-enrichment, called eutrophica-tion. This may produce even more algal growth, causing fish to suffocate. Here is a perfect example of a long chain of happenings in nature set off without harmful intention.
Sometimes we are tempted to overdo the whole business of pest control in the house, in an effort to deal with problems before they arise. If we use aerosols, vapour strips, disinfectants, sprays, moth proofing, fly repellents, and all the other methods of keeping pests at bay, and if we use them regularly as preventives rather than as cures, we may cause quite a build up of poison, particularly in small houses and kitchens. This can be harmful to human beings and also to household pets. If any substance is killing to any one form of life, such as fly spray, it may be harmful to others without actually killing them. In the house all pesticides based on organ-ochlorines should be avoided, that is, those containing D.D.T., dieldrin, or lindane. Those containing pyreth-rum or derris are safer, and the contents should be listed on the container. Too much D.D.T. and other long-lasting poisons have already been let loose in the world.
There are other ways in which household action can help in dealing with world-wide problems. As modern life grows more complicated, we use far more of everything in the home, not just food, but industrial commodities of all kinds. An example is paper. The world is swallowing paper at a tremendous rate, and paper comes from trees. Every year nearly 200 million tons of wood are used for paper. A single issue of the American New York Times uses wood covering 190 acres of forest. Once gone, these majestic forest trees have gone for hundreds of years, with the food, shelter, and protection they give to many species of life; new forests may grow, but in some cases regeneration may be impossible. It may seem a small thing, but if waste paper could be collected, and re-used, this would be a real contribution to the problem of world conservation. For the same reason, and also because supplies are running short, many other materials and metals should be re-cycled whenever possible.
Water is a precious commodity, and one we tend to use quite unthinkingly. We each use about 90 gallons a day, and this figure is rising rapidly, as more and more people want more and more water. All industrial processes are greedy water users. Up to 100,000 gallons of water may be used in making a single car. So more reservoirs have to be constructed, again involving much loss of land available for wild life, and destruction of habitats. A well-known example is the reservoir at Cow Green, in Upper Teesdale, to meet the industrial needs of Teesside. Many acres of the most beautiful moorland have gone for ever, and there may be quite incalculable effects on a wide surrounding area, although it is one of the most interesting botanical sites in the world, with unique associations of plants.
As it happens, the industrial use of water is so much greater than domestic use that economy in the home does not help much. But the time may come when our drinking water will come to us, like milk, in bottles, and a much lower standard of purity have to be accepted for other purposes, in the interests of water economy. In the meantime, other forms of water supply such as the desalination of sea water, or the construction of barrages across areas like the Wash or Morecambe Bay, will have to be explored, and some assessment made of the damage they in their turn might do to wild life habitats.