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Botany
From Wikipedia, the free encyclopedia
Botany, plant science(s), phytology, or plant biology is a branch of biology and is the scientific study of plant life and development. Botany covers a wide range of scientific disciplines that study plants, algae, and fungi including: structure, growth, reproduction, metabolism, development, diseases, chemical properties, and evolutionary relationships between the different groups. Botany began with early human efforts to identify edible, medicinal and poisonous plants, making botany one of the oldest sciences. From this ancient interest in plants, the scope of botany has increased to include the study of over 550,000 species of living organisms.
Scope and importance of botany
As with other life forms in biology, plant life can be studied from different perspectives, from the molecular, genetic and biochemical level through organelles, cells, tissues, organs, individuals, plant populations, and communities of plants. At each of these levels a botanist might be concerned with the classification (taxonomy), structure (anatomy and morphology), or function (physiology) of plant life.
Historically all living things were grouped as animals or plants,[1] and botany covered all organisms not considered animals. Some organisms once included in the field of botany are no longer considered to belong to the plant kingdom – these include fungi (studied in mycology), lichens (lichenology), bacteria (bacteriology), viruses (virology) and single-celled algae, which are now grouped as part of the Protista. However, attention is still given to these groups by botanists, and fungi, lichens, bacteria and photosynthetic protists are usually covered in introductory botany courses.
The study of plants is vital because they are a fundamental part of life on Earth, which generates the oxygen, food, fibres, fuel and medicine that allow humans and other life forms to exist. Through photosynthesis, plants absorb carbon dioxide, a greenhouse gas that in large amounts can affect global climate. Additionally, they prevent soil erosion and are influential in the water cycle. A good understanding of plants is crucial to the future of human societies as it allows us to:
- Produce food to feed an expanding population
- Understand fundamental life processes
- Produce medicine and materials to treat diseases and other ailments
- Understand environmental changes more clearly
Paleobotanists study ancient plants in the fossil record. It is believed that early in the Earth's history, the evolution of photosynthetic plants altered the global atmosphere of the earth, changing the ancient atmosphere by oxidation.
Human nutrition
Virtually all foods eaten come from plants, either directly from staple foods and other fruit and vegetables, or indirectly through livestock or other animals, which rely on plants for their nutrition. Plants are the fundamental base of nearly all food chains because they use the energy from the sun and nutrients from the soil and atmosphere, converting them into a form that can be consumed and utilized by animals; this is what ecologists call the first trophic level. Botanists also study how plants produce food we can eat and how to increase yields and therefore their work is important in mankind's ability to feed the world and provide food security for future generations, for example, through plant breeding. Botanists also study weeds, plants which are considered to be a nuisance in a particular location. Weeds are a considerable problem in agriculture, and botany provides some of the basic science used to understand how to minimize 'weed' impact in agriculture and native ecosystems. Ethnobotany is the study of the relationships between plants and people.
Fundamental life processes
Plants are convenient organisms in which fundamental life processes (like cell division and protein synthesis) can be studied, without the ethical dilemmas of studying animals or humans. The genetic laws of inheritance were discovered in this way by Gregor Mendel, who was studying the way pea shape is inherited. What Mendel learned from studying plants has had far reaching benefits outside of botany. Additionally, Barbara McClintock discovered 'jumping genes' by studying maize. These are a few examples that demonstrate how botanical research has an ongoing relevance to the understanding of fundamental biological processes.
Medicine and materials
Many medicinal and recreational drugs, like tetrahydrocannabinol, caffeine, and nicotine come directly from the plant kingdom. Others are simple derivatives of botanical natural products; for example, aspirin is based on the pain killer salicylic acid which originally came from the bark of willow trees. As well, the narcotic analgesics such as morphine are derived from the opium poppy.[2] There may be many novel cures for diseases provided by plants, waiting to be discovered. Popular stimulants like coffee, chocolate, tobacco, and tea also come from plants. Most alcoholic beverages come from fermenting plants such as barley (beer), rice (sake) and grapes (wine).
Plants also provide us with many natural materials, such as hemp, cotton, wood, paper, linen, vegetable oils, some types of rope, and rubber. The production of silk would not be possible without the cultivation of the mulberry plant. Sugarcane, rapeseed, soy and other plants with a highly-fermentable sugar or oil content have recently been put to use as sources of biofuels, which are important alternatives to fossil fuels (see biodiesel).
Environmental changes
Plants can also help us understand changes in on our environment in many ways.
- Understanding habitat destruction and species extinction is dependent on an accurate and complete catalog of plant systematics and taxonomy.
- Plant responses to ultraviolet radiation can help us monitor problems like ozone depletion.
- Analyzing pollen deposited by plants thousands or millions of years ago can help scientists to reconstruct past climates and predict future ones, an essential part of climate change research.
- Recording and analyzing the timing of plant life cycles are important parts of phenology used in climate-change research.
- Lichens, which are sensitive to atmospheric conditions, have been extensively used as pollution indicators.
In many different ways, plants can act a little like the 'miners' canary', an early warning system alerting us to important changes in our environment. In addition to these practical and scientific reasons, plants are extremely valuable as recreation for millions of people who enjoy gardening, horticultural and culinary uses of plants every day.
Etymology
From Greek βοτάνη = "pasture, grass, fodder", perhaps via the idea of a livestock keeper needing to know which plants are safe for livestock to eat.
History
Early botany
Early examples of plant taxonomy occur in the Rigveda, that divides plants into Vṛska (tree), Osadhi (herbs useful to humans) and Virudha (creepers), which are then further subdivided. The Atharvaveda divides plants into eight classes, Visakha (spreading branches), Manjari (leaves with long clusters), Sthambini (bushy plants), Prastanavati (which expands); Ekasṛnga (those with monopodial growth), Pratanavati (creeping plants), Amsumati (with many stalks), and Kandini (plants with knotty joints). The Taittiriya Samhita classifies the plant kingdom into vṛksa, vana and druma (trees), visakha (shrubs with spreading branches), sasa (herbs), amsumali (a spreading or deliquescent plant), vratati (climber), stambini (bushy plant), pratanavati (creeper), and alasala (those spreading on the ground).
Manusmriti – Law book of Hindus – proposed a classification of plants in eight major categories. Charaka Samhitā and Sushruta Samhita and the Vaisesikas also present an elaborate taxonomy.