Plants food being part of human food

Our dependence on green organisms to produce the oxygen in the air we breathe and to remove the carbon dioxide we give off doesn’t stop there. Plant are also the sources of products that are so much a part of human society that we largely take them for granted. We know, of course, that rice, corn, potatoes, and other vegetables are plants (Fig.1); but all foods, including meat, fish, poultry, eggs, cheese, and milk, to mention just a few, owe their existence to plants. Condiments such as spices (Fig. 2) and luxuries such as perfumes are being produced by plants, as are some dyes, adhesives, digestible surgical stitching fiber, food stabilizers, beverages (Fig.3), and emulsifiers.

Our houses are constructed with lumber from trees, which also furnish the cellulose for paper, cardboard, and synthetic fibers. Some of our clothing, camping equipment, bedding, draperies, and other textile goods are made from fibers of many different plant families (Fig.4). Coal is fossilized plant material, and oil probably came from microscopic green organisms or animals that either directly or indirectly were plant consumers. All medicines and drugs at one time came from plants, fungi, or bacteria, and many important ones, including most of the antibiotics, still do (Fig.5).

Figure 1A Rice cakes food being manufactured. Unprocessed rice is poured into small ovens where the kernels are expanded. The kernels are then compressed into cakes, which are conveyed by belt to a packaging area.
Figure 1A Rice cakes food being manufactured. Unprocessed rice is poured into small ovens where the kernels are expanded. The kernels are then compressed into cakes, which are conveyed by belt to a packaging area.

Figure 1B Part of a food produce section in a supermarket.
Figure 1B Part of a food produce section in a supermarket.



Figure 2 Some of the spices derived from plants.
Figure 2 Some of the spices derived from plants.

Microscopic organisms play a vital role in recycling both plant and animal wastes and aid in the building of healthy soils. Others are responsible for human diseases and allergies. Although gluts or shortages of oil and other fossil fuels may at present be politically or economically manipulated, there is no question that these fuels are finite and eventually will disappear. Accordingly, the development of alternative energy sources is receiving increased attention.

Methane gas, which can be used as a substitute for natural gas, has been produced from animal manures and decomposed plants in numerous villages in India and elsewhere for many years, and after several years of trial on a small scale in the United States, the production of methane on a larger scale from human sewage is being investigated. Potatoes, grains, and other sources of carbohydrates are currently used in the manufacture of alcohols, some of which are being blended with gasoline ("gasohol"), and such uses may increase in the future. In fact, electric cars, as well as buses and automobiles that can run on propane and either methanol (wood alcohol) or gasoline—or a mixture of both—are now in use in many communities in the United States and other parts of the world.

Figure 3A Ripening coffee berries. They are picked by hand when they are red. The seeds are extracted for roasting after the berries have been fermented.
Figure 3A Ripening coffee berries. They are picked by hand when they are red. The seeds are extracted for roasting after the berries have been fermented.


Figure 3B Coffee beans cooling after being roasted.
Figure 3B Coffee beans cooling after being roasted.

Figure 4 Cotton plants. The white fibers, in which seeds are embedded, are the source of textiles and fabrics. The seeds are the source of vegetable oils used in margarine and shortening. After the oils have been extracted, the remaining "cotton cake" is used for cattle feed.
Figure 4 Cotton plants. The white fibers, in which seeds are embedded, are the source of textiles and fabrics. The seeds are the source of vegetable oils used in margarine and shortening. After the oils have been extracted, the remaining "cotton cake" is used for cattle feed.


Figure 5 A Penicillium colony. The tiny beads of fluid on the surface contain part penicillin, widely used as an antibiotic.
Figure 5 A Penicillium colony. The tiny beads of fluid on the surface contain part penicillin, widely used as an antibiotic.


What of plants and the future? As you read this, the population of the earth already has exceeded 6 billion persons, every one of whom needs food, clothing, and shelter in order to survive. To ensure survival, a majority of us eventually may need to learn not only how to cultivate food plants but also how to use plants in removing pollutants from water (Fig.6), in making land productive again, and in renewing urban areas. In addition, many more of us may need to be involved in helping halt the destruction of plant habitats caused primarily by the huge increase in the number of earth’s inhabitants.

Although at present the idea that humanity may not be able to save itself from itself may seem radical, there are a few who have suggested that it might become necessary in the future to emigrate to another planet. If so, microscopic algae could play a vital role in space exploration. Experiments with portable oxygen generators have been in progress for many years. Tanks of water teeming with tiny green algae are taken aboard a spacecraft and installed so that they are exposed to light for at least part of the time. The algae not only produce oxygen, which the spacecraft inhabitants can breathe, but they also utilize the waste carbon dioxide produced by respiration. As the algae multiply, they can be fed to a special kind of shrimp, which, in turn, multiply and become food for the space travelers. Other wastes are recycled by different microscopic organisms.

When this self-supporting arrangement, called a closed system, is perfected, the range of spacecraft should greatly increase because heavy oxygen tanks will not be necessary, and the amount of food reserves needed will be reduced.

Inhabitants of undeveloped areas still use plants for food, shelter, clothing, and medicine and also in hunting and fishing. Today, small teams of botanists, anthropologists, and medical doctors are interviewing medical practitioners and herbal healers in remote tropical regions and taking notes on various uses of plants by primitive peoples. These scientists are doing so in the hope of preserving at least some plants with potential for modern civilization before disruption of their habitats results in their extinction.

Figure 6 A polluted waterway in an urban area.
Figure 6 A polluted waterway in an urban area.

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