Food s with a
combine harvester Human cultivation of plants is the core of
agriculture, which in turn has
played a key role in the history of world civilizations. Humans depend on flowering plants for
food, either directly or as feed in
animal husbandry. More broadly, agriculture includes
agronomy for arable crops,
horticulture for vegetables and fruit, and
forestry, including both flowering plants and conifers, for timber. About 7,000 species of plant have been used for food, though most of today's food is derived from only 30 species. The major
staples include
cereals such as rice and wheat, starchy roots and tubers such as
cassava and
potato, and legumes such as
peas and
beans.
Vegetable oils such as
olive oil and
palm oil provide
lipids, while fruit and
vegetables contribute
vitamins and minerals to the diet.
Coffee,
tea, and
chocolate are major crops whose
caffeine-containing products serve as mild stimulants. The study of plant uses by people is called economic botany or
ethnobotany.
Medicines , from an Arabic
Dioscorides, 1224
Medicinal plants are a primary source of
organic compounds, both for their medicinal and physiological effects, and for the industrial
synthesis of a vast array of organic chemicals. Many hundreds of medicines, as well as
narcotics, are derived from plants, both traditional medicines used in
herbalism and chemical substances purified from plants or first identified in them, sometimes by ethnobotanical search, and then synthesised for use in modern medicine. Modern medicines derived from plants include
aspirin,
taxol,
morphine,
quinine,
reserpine,
colchicine,
digitalis and
vincristine.
Plants used in herbalism include
ginkgo,
echinacea,
feverfew, and
Saint John's wort. The
pharmacopoeia of
Dioscorides, , describing some 600 medicinal plants, was written between 50 and 70 CE and remained in use in Europe and the Middle East until around 1600 CE; it was the precursor of all modern pharmacopoeias.
Nonfood products in storage for later processing at a
sawmill Plants grown as industrial crops are the source of a wide range of products used in manufacturing. Nonfood products include
essential oils,
natural dyes, pigments,
waxes,
resins,
tannins, alkaloids,
amber and
cork. Products derived from plants include soaps, shampoos, perfumes, cosmetics, paint, varnish, turpentine, rubber,
latex, lubricants, linoleum, plastics, inks, and
gums. Renewable fuels from plants include
firewood,
peat and other
biofuels. The
fossil fuels
coal,
petroleum and
natural gas are derived from the remains of aquatic organisms including
phytoplankton in
geological time. Many of the coal fields date to the
Carboniferous period of
Earth's history. Terrestrial plants also form
type III kerogen, a source of natural gas. Structural resources and fibres from plants are used to construct dwellings and to manufacture clothing.
Wood is used for buildings, boats, and furniture, and for smaller items such as
musical instruments and sports equipment. Wood is
pulped to make
paper and
cardboard. Cloth is often made from
cotton,
flax,
ramie or synthetic fibres such as
rayon, derived from plant cellulose.
Thread used to sew cloth likewise comes in large part from cotton.
Ornamental plants at Niedernhall in Germany Thousands of plant species are cultivated for their beauty and to provide shade, modify temperatures, reduce wind, abate noise, provide privacy, and reduce soil erosion. Plants are the basis of a multibillion-dollar per year tourism industry, which includes travel to
historic gardens,
national parks,
rainforests,
forests with colourful autumn leaves, and festivals such as
Japan's and
America's cherry blossom festivals. Plants may be grown indoors as
houseplants, or in specialized buildings such as
greenhouses. Plants such as Venus flytrap,
sensitive plant and
resurrection plant are sold as novelties. Art forms specializing in the arrangement of cut or living plant include
bonsai,
ikebana, and the arrangement of cut or dried flowers.
Ornamental plants have sometimes changed the course of history, as in
tulipomania.
In science used
maize to study inheritance of traits. The
traditional study of plants is the science of
botany. Basic biological research has often used plants as its
model organisms. In
genetics, the breeding of pea plants allowed
Gregor Mendel to derive the
basic laws governing inheritance, and examination of chromosomes in maize allowed
Barbara McClintock to demonstrate their connection to inherited traits. The plant
Arabidopsis thaliana is used in laboratories as a model organism to understand how
genes control the growth and development of plant structures.
Tree rings provide a method of dating in
archeology, and a record of
past climates. The study of plant fossils, or
paleobotany, provides information about the evolutions of plants,
paleogeographical reconstructions, and past climate change. Plant fossils can also help determine the age of rocks.
In mythology, religion, and culture Plants,
including trees, appear in mythology, religion, and
literature. In multiple
Indo-European, Siberian, and
Native American religions, the
world tree motif is depicted as a colossal tree growing on the earth, supporting the heavens, and with its roots reaching into the
underworld. It may also appear as a cosmic tree or an eagle and serpent tree. Forms of the world tree include the archetypal
tree of life, which is in turn connected to the Eurasian concept of the
sacred tree. Another widespread ancient motif, found for example in Iran, has a tree of life flanked by a pair of
confronted animals. Flowers are often used as memorials, gifts and to mark special occasions such as births, deaths, weddings and holidays. Flower arrangements may be used to send
hidden messages. Plants and especially flowers form the subjects of many paintings.
Negative effects is an
invasive species in
Texas.
Weeds are commercially or aesthetically undesirable plants growing in managed environments such as in agriculture and gardens. People have spread many plants beyond their native ranges; some of these plants have become
invasive, damaging existing ecosystems by displacing native species, and sometimes becoming serious weeds of cultivation. Some plants that produce
windblown pollen, including grasses, invoke
allergic reactions in people who suffer from
hay fever. Many plants
produce toxins to
protect themselves from herbivores. Major classes of plant toxins include
alkaloids,
terpenoids, and
phenolics. These can be harmful to humans and livestock by ingestion or, as with
poison ivy, by contact. Some plants have negative effects on other plants, preventing seedling growth or the growth of nearby plants by releasing
allopathic chemicals. == See also ==