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1、Chapter 29: The Importance of Plants29-1 Plants and People29-2 Plants and the EnvironmentI. Botany Branch of biology dealing with the 350,000 species of plants.29-1 Plants and PeopleII. Plants as Food Fewer than twenty plant species provide more than 90 percent of our food supply; 10,000 plant speci
2、es have shown value as foods.(1) Agriculture (11,000 years ago) Farmers propagated plants that had valuable traits, including high fruit yield.(2) Cultivars (i.e., cultivate-variety) Crops that evolved through artificial selection (e.g., Thompson Seedless Grapes, MacIntosh Apples, Valencia Oranges,
3、Yoshiro Cherries.)III. Food Crops Classified by use and by family but not phylogeny.CategoryDescriptionExamplesCerealsgrasses with edible dry fruit known as grainsrice, wheat, corn, oats, ryeRoot cropsroots or underground stems rich in carbohydratespotato, sweet potato, taroLegumesmembers of the pea
4、 family with protein-rich seeds in podssoybean, peanut, bean, pea, alfalfaFruitsthe part of a flowering plant containing seedsapple, banana, grape, orange, pineappleVegetablesleaves, stems, seeds, and roots of soft plantsspinach, sweet corn, tomato, turnipNutsa one-seed fruit with a hard outer layer
5、peanut, walnut, pecan, coconut, almondSpicesplant parts other than the leaf that add taste to foodpepper, vanilla, gingerHerbsplant leaves that add taste to foodsage, dill, basil, mint, oreganoCategoryDescriptionExamplesCerealsgrasses with edible dry fruit known as grainsrice, wheat, corn, oats, rye
6、Root cropsroots or underground stems rich in carbohydratespotato, sweet potato, taroLegumesmembers of the pea family with protein-rich seeds in podssoybean, peanut, bean, pea, alfalfaFruitsthe part of a flowering plant containing seedsapple, banana, grape, orange, pineappleVegetablesleaves, stems, s
7、eeds, and roots of soft plantsspinach, sweet corn, tomato, turnipNutsa one-seed fruit with a hard outer layerpeanut, walnut, pecan, coconut, almondSpicesplant parts other than the leaf that add taste to foodpepper, vanilla, gingerHerbsplant leaves that add taste to foodsage, dill, basil, mint, orega
8、no(A) Cereals (provide 50% of the worldwide calories in the human diet) Grasses containing grains, the edible, dry fruits of a cereal. Rice, wheat, corn, oats, sorghum, rye and millet are all examples of cereal crops. (B) Root Crops Roots or underground stems that are rich in carbohydrates. Potatoes
9、, beets, carrots, radishes, rutabagas, turnips, and cassava (tapioca).(C) Legumes (mutualism with the N-fixing bacteria Rhizobum in the roots) Members of the pea family and bear protein-rich seeds in pods. Soybean, Alfalfa, Peanuts, and Clover.(D) Fruits, Vegetables, and Nuts A group of classifiable
10、 plant products consumed for nutrition.(1) Fruits Part of the flowering plant that usually contains the seeds. (e.g., tomatoes, green beans, squash, etc)(2) Vegetables Derived from the leaves, stems, seeds, and roots of non-woody plants. (e.g., spinach, celery, lettuce, carrots, etc)(3) Nuts Hard ou
11、ter layer and a dry, one-seed fruit. (e.g., almonds, walnuts, pecans, hazelnuts, cashews, etc)Assortment of true and false nuts: A. Hazelnut (Corylus americana), B. Pecan (Carya illinoensis), C. Peanut (Arachis hypogea), D. Macadamia Nut (Macadamia integrifolia), E. Almond (Prunus amygdalus), F. Bra
12、zil Nut (Bertholletia excelsa), G. Chestnut (Castanea dentata), H. Kukui Nut (Aleurites molucanna), I. Water Chestnut (Trapa bicornis), J. Walnut (Juglans regia). True nuts: A. Drupes: B., D., E., H., I. Seeds: F.; Legumes: C. Note: The pecan (B) and walnut (J) are also considered to be a true nuts
13、by some botanists. (E) Spices, Herbs, and Flavorings Spices are derived from non-leaf tropical plant parts and herbs are usually derived from leaves and can be temperate; flavorings like chocolate are placed in a separate category.(1) Quinine (a type of flavor) Flavor derived from the bark of the ci
14、nchona tree used to make tonic water and also treat malaria.(F) Food Production Massive food shortages have not occurred due to increased use of irrigation, fertilizers, pesticides, and improved cultivars.(1) Fertilizers Supply plants with essential minerals and nutrients like nitrogen and phosphoro
15、us.(2) Pesticides Chemicals designed to prevent competition for limited resources, typically with herbivorous insects.IV. Nonfood Uses of Plants Include industrial, recreational, atmospheric, and medicinal forms of utilitarian value.(A) Medicines Plants were our first medicines, and early plant biol
16、ogists or botanists like Carolous Linnaeus, were often medical doctors.(1) Aspirin (acetylsalicylic acid) Derived from the bark of the white willow tree (Salix genus)(B) Clothing and Fabric Dyes Cotton (hairs attached to seed of cotton plant), Linen (flax plant), and artificial fabrics (rayon)processed wood fibers, tannin (many trees) used to toughen leather products. Dyes derived from
