Plants Play Key Roles in Society and Nature

Section Summary ● Plants have many key roles in human society, providing food, medicines, building materials, and energy. ● The human food supply is based on the cultivation of relatively few species of plants. ● The use of biofuels has environmental, economic, and social costs and benefits. ● Plants provide a number of ecosystem services. ● Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own needs.

Canola – a Canadian Plant Many foods were in short supply in Canada during World War II, especially foods with military uses. Oil was needed to lubricate machinery, and there was little oil available for cooking. In 1942, Canada purchased 20 kg of rapeseed from Argentina and by 1948, ha of rapeseed plants were growing in the Prairies.

Canola – a Canadian Plant But there was a problem: rapeseed oil did not taste very good. It contained two compounds that give mustard and radishes their sharp flavour. Canadian scientists used traditional plant- breeding techniques to improve the taste of rapeseed oil by reducing levels of both compounds. The new form of rapeseed was renamed “canola.” Canola comes from Canada plus oleum, which is Latin for oil.

Canola, the world’s only “made in Canada” plant, is now grown on five million hectares across Ontario and the Prairies. Canola is one of the healthiest edible oils Once the oil is extracted, the remaining meal is a high-protein feed for farm animals and aquaculture. Canola – a Canadian Plant

Canola oil can also be made into biodiesel, a renewable fuel that replaces diesel made from fossil fuels. In the 1990s, canola was genetically modified (GM) with the insertion of foreign genes that are associated with herbicide resistance. About 80 percent of the canola grown in Canada is GM. Canola – a Canadian Plant

Canada’s Food Crops Today, almost all the human food supply is based on the cultivation of only 14 species of plants. Canada’s main crops are wheat, canola, barley, corn, soybeans, potatoes, flax, and oats WHEAT RICE MAIZE POTATOES SWEET POTATOES MANIOC SUGARCANE SUGARBEET COMMON BEANS SOYBEANS BARLEY SORGHUM COCONUTS BANANAS

Most Important Crops The most important crops in the world are cereal grains and legumes, members of the pea and bean family. Half of the protein consumed by people worldwide comes from cereal grains.

Most Important Crops Rice is the most important cereal grain throughout Asia. Wheat is the most common grain in North American and European diets. Another 15 percent of human dietary protein comes from the dried fruits of legumes.

Food Plants Food comes from all plant parts: –leaves –stems –roots –seeds –fruits

Food Plants Spices come from strongly flavoured plant parts: –bark (cinnamon) –fruits; (black pepper, vanilla) –seed (cardamom) –flower (cloves)

Food Plants Herbs such as basil, thyme, and mint are the leaves of aromatic plants. One of the world’s most expensive herbs, saffron, is the male floral parts (anthers) of a crocus flower, collected laboriously by hand.

Many of the foods we eat contain hidden processed plant products, such as sugars from corn or beets and oil from canola or sunflowers. We use thickeners, such as guar gum and corn starch Soy protein is often added to increase protein and improve texture.

Plants as Pharmaceuticals More than 120 prescription and non- prescription drugs, ranging from stimulants to cancer treatments to laxatives, are extracted from plants. 25 percent of drug prescriptions contain a plant product

Researchers have investigated fewer than 5000 of the known plant species as potential sources of new medicines. Human activities threaten many plants before their potential uses can be assessed. Plants as Pharmaceuticals

The tropical rainforest is losing plant species faster than any of Earth’s ecosystems. It could be a “medicine chest” of healing plants that will become extinct before they are even discovered. Plants as Pharmaceuticals

Plants as a Source of Fuel Plants are the main source of fuel for human activities. Humans have used wood and peat fires to cook food and provide heat for over years. Fossil fuels such as coal, oil, and natural gas come from the fossilized remains of plants that died during the Carboniferous period.

Biofuels Biofuels are energy sources produced from renewable organic materials, including plants and organic waste. Biodiesel is produced from plant or animal fats or used cooking oil. The Canadian government funds programs that encourage the development and production of biofuels.

Biofuels Biofuels offer the hope of renewable fuels with lower greenhouse gas emissions. Using crops for fuel may reduce the availability of agricultural land for food crops and increase the cost of food.

Plants as a Source of Industrial and Building Materials Plants and plant products play many key roles in building, industry, and the home. Hardwoods are dense woods of angiosperms used to make high quality furniture and flooring.

Plants as a Source of Industrial and Building Materials Softwoods come from gymnosperms Softwoods are used for furniture and buildings The long fibres of softwoods means that they are also suitable for producing pulp, used for paper and cardboard production.

Canada’s Softwood Industry Canada is one of the world’s largest producers of softwood lumber and its products. We supply about one-third of the softwood lumber used in the United States. This trade earns Canada $8.5 billion a year. About Canadian jobs and 300 communities depend on Canada’s softwood lumber industry.

Industrial Uses of Plants Linseed oil is used as a furniture finish. Castor oil is used as motor oil and as a lubricant for hydraulic systems in heavy machinery. Oil-based products currently dominate industry

Industrial Uses of Plants New technologies have led to the production of inexpensive plant-based industrial products. Plant-based inks, paints, plastics, and dyes are becoming less expensive and more popular.

Other Uses of Plants When you use a pencil or pen to jot down a note on a piece of paper, the pencil, the ink, and the paper all come from plants. The money you spend, the violin you play, makeup, a baseball bat: all of these products are made from plants.

Other Uses of Plants Many of our clothes are made from cotton, flax, hemp, or sisal fibres Rayon is made from chemically processed cellulose derived from wood, cotton, or bamboo.

Ecosystem Services Ecosystem services are the beneficial processes carried out by living things that are necessary to sustain life on Earth. Plants play a key role in nutrient cycles. They are a food source for consumers They enrich the soil by adding usable nutrients to it.

Ecosystem Services Plant roots bind soil, reducing erosion in terrestrial ecosystems and coastal areas. Plants are also capable of storing or detoxifying toxins and pollutants. Some house plants, such as the spider plant and philodendron, reduce indoor air pollutants.

Plants in parks and along city streets improve air quality, cool the air, reduce storm water runoff, reduce noise levels, and provide habitat for animals Some studies show a reduction in crime and increase in personal relaxation in urban areas that have more vegetation. Trees increase property values and reduce energy use through shading and wind reduction. Ecosystem Services in Urban Centres

Homework Page 366 #