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In 1922, Egypt, which had been declared a British protectorate at the outbreak of the First World War, was granted formal independence, though it continued to be a British client state until 1954. British troops remained stationed in Egypt until the signing of the Anglo-Egyptian Treaty in 1936, under which it was agreed that the troops would withdraw but continue to occupy and defend the Suez Canal zone. In return, Egypt was assisted to join the League of Nations. Iraq, a British mandate since 1920, also gained membership of the League in its own right after achieving independence from Britain in 1932. In Palestine, Britain was presented with the problem of mediating between the Arab and Jewish communities. The 1917 Balfour Declaration, which had been incorporated into the terms of the mandate, stated that a national home for the Jewish people would be established in Palestine, and Jewish immigration allowed up to a limit that would be determined by the mandatory power. This led to increasing conflict with the Arab population, who openly revolted in 1936. As the threat of war with Germany increased during the 1930s, Britain judged the support of the Arab population in the Middle East as more important than the establishment of a Jewish homeland, and shifted to a pro-Arab stance, limiting Jewish immigration and in turn triggering a Jewish insurgency. |
The ability of the Dominions to set their own foreign policy, independent of Britain, was recognised at the 1923 Imperial Conference. Britain's request for military assistance from the Dominions at the outbreak of the Chanak Crisis the previous year had been turned down by Canada and South Africa, and Canada had refused to be bound by the 1923 Treaty of Lausanne. After pressure from Ireland and South Africa, the 1926 Imperial Conference issued the Balfour Declaration, declaring the Dominions to be "autonomous Communities within the British Empire, equal in status, in no way subordinate one to another" within a "British Commonwealth of Nations". This declaration was given legal substance under the 1931 Statute of Westminster. The parliaments of Canada, Australia, New Zealand, the Union of South Africa, the Irish Free State and Newfoundland were now independent of British legislative control, they could nullify British laws and Britain could no longer pass laws for them without their consent. Newfoundland reverted to colonial status in 1933, suffering from financial difficulties during the Great Depression. Ireland distanced itself further from Britain with the introduction of a new constitution in 1937, making it a republic in all but name. |
After the German occupation of France in 1940, Britain and the empire stood alone against Germany, until the entry of the Soviet Union to the war in 1941. British Prime Minister Winston Churchill successfully lobbied President Franklin D. Roosevelt for military aid from the United States, but Roosevelt was not yet ready to ask Congress to commit the country to war. In August 1941, Churchill and Roosevelt met and signed the Atlantic Charter, which included the statement that "the rights of all peoples to choose the form of government under which they live" should be respected. This wording was ambiguous as to whether it referred to European countries invaded by Germany, or the peoples colonised by European nations, and would later be interpreted differently by the British, Americans, and nationalist movements. |
In December 1941, Japan launched, in quick succession, attacks on British Malaya, the United States naval base at Pearl Harbor, and Hong Kong. Churchill's reaction to the entry of the United States into the war was that Britain was now assured of victory and the future of the empire was safe, but the manner in which British forces were rapidly defeated in the Far East irreversibly harmed Britain's standing and prestige as an imperial power. Most damaging of all was the fall of Singapore, which had previously been hailed as an impregnable fortress and the eastern equivalent of Gibraltar. The realisation that Britain could not defend its entire empire pushed Australia and New Zealand, which now appeared threatened by Japanese forces, into closer ties with the United States. This resulted in the 1951 ANZUS Pact between Australia, New Zealand and the United States of America. |
Though Britain and the empire emerged victorious from the Second World War, the effects of the conflict were profound, both at home and abroad. Much of Europe, a continent that had dominated the world for several centuries, was in ruins, and host to the armies of the United States and the Soviet Union, who now held the balance of global power. Britain was left essentially bankrupt, with insolvency only averted in 1946 after the negotiation of a $US 4.33 billion loan (US$56 billion in 2012) from the United States, the last instalment of which was repaid in 2006. At the same time, anti-colonial movements were on the rise in the colonies of European nations. The situation was complicated further by the increasing Cold War rivalry of the United States and the Soviet Union. In principle, both nations were opposed to European colonialism. In practice, however, American anti-communism prevailed over anti-imperialism, and therefore the United States supported the continued existence of the British Empire to keep Communist expansion in check. The "wind of change" ultimately meant that the British Empire's days were numbered, and on the whole, Britain adopted a policy of peaceful disengagement from its colonies once stable, non-Communist governments were available to transfer power to. This was in contrast to other European powers such as France and Portugal, which waged costly and ultimately unsuccessful wars to keep their empires intact. Between 1945 and 1965, the number of people under British rule outside the UK itself fell from 700 million to five million, three million of whom were in Hong Kong. |
The pro-decolonisation Labour government, elected at the 1945 general election and led by Clement Attlee, moved quickly to tackle the most pressing issue facing the empire: that of Indian independence. India's two major political parties—the Indian National Congress and the Muslim League—had been campaigning for independence for decades, but disagreed as to how it should be implemented. Congress favoured a unified secular Indian state, whereas the League, fearing domination by the Hindu majority, desired a separate Islamic state for Muslim-majority regions. Increasing civil unrest and the mutiny of the Royal Indian Navy during 1946 led Attlee to promise independence no later than 1948. When the urgency of the situation and risk of civil war became apparent, the newly appointed (and last) Viceroy, Lord Mountbatten, hastily brought forward the date to 15 August 1947. The borders drawn by the British to broadly partition India into Hindu and Muslim areas left tens of millions as minorities in the newly independent states of India and Pakistan. Millions of Muslims subsequently crossed from India to Pakistan and Hindus vice versa, and violence between the two communities cost hundreds of thousands of lives. Burma, which had been administered as part of the British Raj, and Sri Lanka gained their independence the following year in 1948. India, Pakistan and Sri Lanka became members of the Commonwealth, while Burma chose not to join. |
The British Mandate of Palestine, where an Arab majority lived alongside a Jewish minority, presented the British with a similar problem to that of India. The matter was complicated by large numbers of Jewish refugees seeking to be admitted to Palestine following the Holocaust, while Arabs were opposed to the creation of a Jewish state. Frustrated by the intractability of the problem, attacks by Jewish paramilitary organisations and the increasing cost of maintaining its military presence, Britain announced in 1947 that it would withdraw in 1948 and leave the matter to the United Nations to solve. The UN General Assembly subsequently voted for a plan to partition Palestine into a Jewish and an Arab state. |
Following the defeat of Japan in the Second World War, anti-Japanese resistance movements in Malaya turned their attention towards the British, who had moved to quickly retake control of the colony, valuing it as a source of rubber and tin. The fact that the guerrillas were primarily Malayan-Chinese Communists meant that the British attempt to quell the uprising was supported by the Muslim Malay majority, on the understanding that once the insurgency had been quelled, independence would be granted. The Malayan Emergency, as it was called, began in 1948 and lasted until 1960, but by 1957, Britain felt confident enough to grant independence to the Federation of Malaya within the Commonwealth. In 1963, the 11 states of the federation together with Singapore, Sarawak and North Borneo joined to form Malaysia, but in 1965 Chinese-majority Singapore was expelled from the union following tensions between the Malay and Chinese populations. Brunei, which had been a British protectorate since 1888, declined to join the union and maintained its status until independence in 1984. |
In 1951, the Conservative Party returned to power in Britain, under the leadership of Winston Churchill. Churchill and the Conservatives believed that Britain's position as a world power relied on the continued existence of the empire, with the base at the Suez Canal allowing Britain to maintain its pre-eminent position in the Middle East in spite of the loss of India. However, Churchill could not ignore Gamal Abdul Nasser's new revolutionary government of Egypt that had taken power in 1952, and the following year it was agreed that British troops would withdraw from the Suez Canal zone and that Sudan would be granted self-determination by 1955, with independence to follow. Sudan was granted independence on 1 January 1956. |
In July 1956, Nasser unilaterally nationalised the Suez Canal. The response of Anthony Eden, who had succeeded Churchill as Prime Minister, was to collude with France to engineer an Israeli attack on Egypt that would give Britain and France an excuse to intervene militarily and retake the canal. Eden infuriated US President Dwight D. Eisenhower, by his lack of consultation, and Eisenhower refused to back the invasion. Another of Eisenhower's concerns was the possibility of a wider war with the Soviet Union after it threatened to intervene on the Egyptian side. Eisenhower applied financial leverage by threatening to sell US reserves of the British pound and thereby precipitate a collapse of the British currency. Though the invasion force was militarily successful in its objectives, UN intervention and US pressure forced Britain into a humiliating withdrawal of its forces, and Eden resigned. |
The Suez Crisis very publicly exposed Britain's limitations to the world and confirmed Britain's decline on the world stage, demonstrating that henceforth it could no longer act without at least the acquiescence, if not the full support, of the United States. The events at Suez wounded British national pride, leading one MP to describe it as "Britain's Waterloo" and another to suggest that the country had become an "American satellite". Margaret Thatcher later described the mindset she believed had befallen the British political establishment as "Suez syndrome", from which Britain did not recover until the successful recapture of the Falkland Islands from Argentina in 1982. |
While the Suez Crisis caused British power in the Middle East to weaken, it did not collapse. Britain again deployed its armed forces to the region, intervening in Oman (1957), Jordan (1958) and Kuwait (1961), though on these occasions with American approval, as the new Prime Minister Harold Macmillan's foreign policy was to remain firmly aligned with the United States. Britain maintained a military presence in the Middle East for another decade. In January 1968, a few weeks after the devaluation of the pound, Prime Minister Harold Wilson and his Defence Secretary Denis Healey announced that British troops would be withdrawn from major military bases East of Suez, which included the ones in the Middle East, and primarily from Malaysia and Singapore. The British withdrew from Aden in 1967, Bahrain in 1971, and Maldives in 1976. |
Britain's remaining colonies in Africa, except for self-governing Southern Rhodesia, were all granted independence by 1968. British withdrawal from the southern and eastern parts of Africa was not a peaceful process. Kenyan independence was preceded by the eight-year Mau Mau Uprising. In Rhodesia, the 1965 Unilateral Declaration of Independence by the white minority resulted in a civil war that lasted until the Lancaster House Agreement of 1979, which set the terms for recognised independence in 1980, as the new nation of Zimbabwe. |
Most of the UK's Caribbean territories achieved independence after the departure in 1961 and 1962 of Jamaica and Trinidad from the West Indies Federation, established in 1958 in an attempt to unite the British Caribbean colonies under one government, but which collapsed following the loss of its two largest members. Barbados achieved independence in 1966 and the remainder of the eastern Caribbean islands in the 1970s and 1980s, but Anguilla and the Turks and Caicos Islands opted to revert to British rule after they had already started on the path to independence. The British Virgin Islands, Cayman Islands and Montserrat opted to retain ties with Britain, while Guyana achieved independence in 1966. Britain's last colony on the American mainland, British Honduras, became a self-governing colony in 1964 and was renamed Belize in 1973, achieving full independence in 1981. A dispute with Guatemala over claims to Belize was left unresolved. |
In 1980, Rhodesia, Britain's last African colony, became the independent nation of Zimbabwe. The New Hebrides achieved independence (as Vanuatu) in 1980, with Belize following suit in 1981. The passage of the British Nationality Act 1981, which reclassified the remaining Crown colonies as "British Dependent Territories" (renamed British Overseas Territories in 2002) meant that, aside from a scattering of islands and outposts the process of decolonisation that had begun after the Second World War was largely complete. In 1982, Britain's resolve in defending its remaining overseas territories was tested when Argentina invaded the Falkland Islands, acting on a long-standing claim that dated back to the Spanish Empire. Britain's ultimately successful military response to retake the islands during the ensuing Falklands War was viewed by many to have contributed to reversing the downward trend in Britain's status as a world power. The same year, the Canadian government severed its last legal link with Britain by patriating the Canadian constitution from Britain. The 1982 Canada Act passed by the British parliament ended the need for British involvement in changes to the Canadian constitution. Similarly, the Constitution Act 1986 reformed the constitution of New Zealand to sever its constitutional link with Britain, and the Australia Act 1986 severed the constitutional link between Britain and the Australian states. In 1984, Brunei, Britain's last remaining Asian protectorate, gained its independence. |
In September 1982, Prime minister Margaret Thatcher travelled to Beijing to negotiate with the Chinese government on the future of Britain's last major and most populous overseas territory, Hong Kong. Under the terms of the 1842 Treaty of Nanking, Hong Kong Island itself had been ceded to Britain in perpetuity, but the vast majority of the colony was constituted by the New Territories, which had been acquired under a 99-year lease in 1898, due to expire in 1997. Thatcher, seeing parallels with the Falkland Islands, initially wished to hold Hong Kong and proposed British administration with Chinese sovereignty, though this was rejected by China. A deal was reached in 1984—under the terms of the Sino-British Joint Declaration, Hong Kong would become a special administrative region of the People's Republic of China, maintaining its way of life for at least 50 years. The handover ceremony in 1997 marked for many, including Charles, Prince of Wales, who was in attendance, "the end of Empire". |
Britain retains sovereignty over 14 territories outside the British Isles, which were renamed the British Overseas Territories in 2002. Some are uninhabited except for transient military or scientific personnel; the remainder are self-governing to varying degrees and are reliant on the UK for foreign relations and defence. The British government has stated its willingness to assist any Overseas Territory that wishes to proceed to independence, where that is an option. British sovereignty of several of the overseas territories is disputed by their geographical neighbours: Gibraltar is claimed by Spain, the Falkland Islands and South Georgia and the South Sandwich Islands are claimed by Argentina, and the British Indian Ocean Territory is claimed by Mauritius and Seychelles. The British Antarctic Territory is subject to overlapping claims by Argentina and Chile, while many countries do not recognise any territorial claims in Antarctica. |
Most former British colonies and protectorates are among the 53 member states of the Commonwealth of Nations, a non-political, voluntary association of equal members, comprising a population of around 2.2 billion people. Sixteen Commonwealth realms voluntarily continue to share the British monarch, Queen Elizabeth II, as their head of state. These sixteen nations are distinct and equal legal entities – the United Kingdom, Australia, Canada, New Zealand, Papua New Guinea, Antigua and Barbuda, The Bahamas, Barbados, Belize, Grenada, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Solomon Islands and Tuvalu. |
Political boundaries drawn by the British did not always reflect homogeneous ethnicities or religions, contributing to conflicts in formerly colonised areas. The British Empire was also responsible for large migrations of peoples. Millions left the British Isles, with the founding settler populations of the United States, Canada, Australia and New Zealand coming mainly from Britain and Ireland. Tensions remain between the white settler populations of these countries and their indigenous minorities, and between white settler minorities and indigenous majorities in South Africa and Zimbabwe. Settlers in Ireland from Great Britain have left their mark in the form of divided nationalist and unionist communities in Northern Ireland. Millions of people moved to and from British colonies, with large numbers of Indians emigrating to other parts of the empire, such as Malaysia and Fiji, and Chinese people to Malaysia, Singapore and the Caribbean. The demographics of Britain itself was changed after the Second World War owing to immigration to Britain from its former colonies. |
Botany, also called plant science(s) or plant biology, is the science of plant life and a branch of biology. A botanist or plant scientist is a scientist who specializes in this field. The term "botany" comes from the Ancient Greek word βοτάνη (botanē) meaning "pasture", "grass", or "fodder"; βοτάνη is in turn derived from βόσκειν (boskein), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists study approximately 400,000 species of living organisms of which some 260,000 species are vascular plants and about 248,000 are flowering plants. |
Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – edible, medicinal and poisonous plants, making it one of the oldest branches of science. Medieval physic gardens, often attached to monasteries, contained plants of medical importance. They were forerunners of the first botanical gardens attached to universities, founded from the 1540s onwards. One of the earliest was the Padua botanical garden. These gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomy, and led in 1753 to the binomial system of Carl Linnaeus that remains in use to this day. |
Modern botany is a broad, multidisciplinary subject with inputs from most other areas of science and technology. Research topics include the study of plant structure, growth and differentiation, reproduction, biochemistry and primary metabolism, chemical products, development, diseases, evolutionary relationships, systematics, and plant taxonomy. Dominant themes in 21st century plant science are molecular genetics and epigenetics, which are the mechanisms and control of gene expression during differentiation of plant cells and tissues. Botanical research has diverse applications in providing staple foods, materials such as timber, oil, rubber, fibre and drugs, in modern horticulture, agriculture and forestry, plant propagation, breeding and genetic modification, in the synthesis of chemicals and raw materials for construction and energy production, in environmental management, and the maintenance of biodiversity. |
Another work from Ancient Greece that made an early impact on botany is De Materia Medica, a five-volume encyclopedia about herbal medicine written in the middle of the first century by Greek physician and pharmacologist Pedanius Dioscorides. De Materia Medica was widely read for more than 1,500 years. Important contributions from the medieval Muslim world include Ibn Wahshiyya's Nabatean Agriculture, Abū Ḥanīfa Dīnawarī's (828–896) the Book of Plants, and Ibn Bassal's The Classification of Soils. In the early 13th century, Abu al-Abbas al-Nabati, and Ibn al-Baitar (d. 1248) wrote on botany in a systematic and scientific manner. |
In the mid-16th century, "botanical gardens" were founded in a number of Italian universities – the Padua botanical garden in 1545 is usually considered to be the first which is still in its original location. These gardens continued the practical value of earlier "physic gardens", often associated with monasteries, in which plants were cultivated for medical use. They supported the growth of botany as an academic subject. Lectures were given about the plants grown in the gardens and their medical uses demonstrated. Botanical gardens came much later to northern Europe; the first in England was the University of Oxford Botanic Garden in 1621. Throughout this period, botany remained firmly subordinate to medicine. |
Physician Valerius Cordus (1515–1544) authored a botanically and pharmacologically important herbal Historia Plantarum in 1544 and a pharmacopoeia of lasting importance, the Dispensatorium in 1546. Naturalist Conrad von Gesner (1516–1565) and herbalist John Gerard (1545–c. 1611) published herbals covering the medicinal uses of plants. Naturalist Ulisse Aldrovandi (1522–1605) was considered the father of natural history, which included the study of plants. In 1665, using an early microscope, Polymath Robert Hooke discovered cells, a term he coined, in cork, and a short time later in living plant tissue. |
During the 18th century, systems of plant identification were developed comparable to dichotomous keys, where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters. The choice and sequence of the characters may be artificial in keys designed purely for identification (diagnostic keys) or more closely related to the natural or phyletic order of the taxa in synoptic keys. By the 18th century, new plants for study were arriving in Europe in increasing numbers from newly discovered countries and the European colonies worldwide. In 1753 Carl von Linné (Carl Linnaeus) published his Species Plantarum, a hierarchical classification of plant species that remains the reference point for modern botanical nomenclature. This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus. For the purposes of identification, Linnaeus's Systema Sexuale classified plants into 24 groups according to the number of their male sexual organs. The 24th group, Cryptogamia, included all plants with concealed reproductive parts, mosses, liverworts, ferns, algae and fungi. |
Increasing knowledge of plant anatomy, morphology and life cycles led to the realisation that there were more natural affinities between plants than the artificial sexual system of Linnaeus had indicated. Adanson (1763), de Jussieu (1789), and Candolle (1819) all proposed various alternative natural systems of classification that grouped plants using a wider range of shared characters and were widely followed. The Candollean system reflected his ideas of the progression of morphological complexity and the later classification by Bentham and Hooker, which was influential until the mid-19th century, was influenced by Candolle's approach. Darwin's publication of the Origin of Species in 1859 and his concept of common descent required modifications to the Candollean system to reflect evolutionary relationships as distinct from mere morphological similarity. |
Botany was greatly stimulated by the appearance of the first "modern" text book, Matthias Schleiden's Grundzüge der Wissenschaftlichen Botanik, published in English in 1849 as Principles of Scientific Botany. Schleiden was a microscopist and an early plant anatomist who co-founded the cell theory with Theodor Schwann and Rudolf Virchow and was among the first to grasp the significance of the cell nucleus that had been described by Robert Brown in 1831. In 1855, Adolf Fick formulated Fick's laws that enabled the calculation of the rates of molecular diffusion in biological systems. |
The discipline of plant ecology was pioneered in the late 19th century by botanists such as Eugenius Warming, who produced the hypothesis that plants form communities, and his mentor and successor Christen C. Raunkiær whose system for describing plant life forms is still in use today. The concept that the composition of plant communities such as temperate broadleaf forest changes by a process of ecological succession was developed by Henry Chandler Cowles, Arthur Tansley and Frederic Clements. Clements is credited with the idea of climax vegetation as the most complex vegetation that an environment can support and Tansley introduced the concept of ecosystems to biology. Building on the extensive earlier work of Alphonse de Candolle, Nikolai Vavilov (1887–1943) produced accounts of the biogeography, centres of origin, and evolutionary history of economic plants. |
Particularly since the mid-1960s there have been advances in understanding of the physics of plant physiological processes such as transpiration (the transport of water within plant tissues), the temperature dependence of rates of water evaporation from the leaf surface and the molecular diffusion of water vapour and carbon dioxide through stomatal apertures. These developments, coupled with new methods for measuring the size of stomatal apertures, and the rate of photosynthesis have enabled precise description of the rates of gas exchange between plants and the atmosphere. Innovations in statistical analysis by Ronald Fisher, Frank Yates and others at Rothamsted Experimental Station facilitated rational experimental design and data analysis in botanical research. The discovery and identification of the auxin plant hormones by Kenneth V. Thimann in 1948 enabled regulation of plant growth by externally applied chemicals. Frederick Campion Steward pioneered techniques of micropropagation and plant tissue culture controlled by plant hormones. The synthetic auxin 2,4-Dichlorophenoxyacetic acid or 2,4-D was one of the first commercial synthetic herbicides. |
20th century developments in plant biochemistry have been driven by modern techniques of organic chemical analysis, such as spectroscopy, chromatography and electrophoresis. With the rise of the related molecular-scale biological approaches of molecular biology, genomics, proteomics and metabolomics, the relationship between the plant genome and most aspects of the biochemistry, physiology, morphology and behaviour of plants can be subjected to detailed experimental analysis. The concept originally stated by Gottlieb Haberlandt in 1902 that all plant cells are totipotent and can be grown in vitro ultimately enabled the use of genetic engineering experimentally to knock out a gene or genes responsible for a specific trait, or to add genes such as GFP that report when a gene of interest is being expressed. These technologies enable the biotechnological use of whole plants or plant cell cultures grown in bioreactors to synthesise pesticides, antibiotics or other pharmaceuticals, as well as the practical application of genetically modified crops designed for traits such as improved yield. |
Modern morphology recognizes a continuum between the major morphological categories of root, stem (caulome), leaf (phyllome) and trichome. Furthermore, it emphasizes structural dynamics. Modern systematics aims to reflect and discover phylogenetic relationships between plants. Modern Molecular phylogenetics largely ignores morphological characters, relying on DNA sequences as data. Molecular analysis of DNA sequences from most families of flowering plants enabled the Angiosperm Phylogeny Group to publish in 1998 a phylogeny of flowering plants, answering many of the questions about relationships among angiosperm families and species. The theoretical possibility of a practical method for identification of plant species and commercial varieties by DNA barcoding is the subject of active current research. |
The study of plants is vital because they underpin almost all animal life on Earth by generating a large proportion of the oxygen and food that provide humans and other organisms with aerobic respiration with the chemical energy they need to exist. Plants, algae and cyanobacteria are the major groups of organisms that carry out photosynthesis, a process that uses the energy of sunlight to convert water and carbon dioxide into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells. As a by-product of photosynthesis, plants release oxygen into the atmosphere, a gas that is required by nearly all living things to carry out cellular respiration. In addition, they are influential in the global carbon and water cycles and plant roots bind and stabilise soils, preventing soil erosion. Plants are crucial to the future of human society as they provide food, oxygen, medicine, and products for people, as well as creating and preserving soil. |
The strictest definition of "plant" includes only the "land plants" or embryophytes, which include seed plants (gymnosperms, including the pines, and flowering plants) and the free-sporing cryptogams including ferns, clubmosses, liverworts, hornworts and mosses. Embryophytes are multicellular eukaryotes descended from an ancestor that obtained its energy from sunlight by photosynthesis. They have life cycles with alternating haploid and diploid phases. The sexual haploid phase of embryophytes, known as the gametophyte, nurtures the developing diploid embryo sporophyte within its tissues for at least part of its life, even in the seed plants, where the gametophyte itself is nurtured by its parent sporophyte. Other groups of organisms that were previously studied by botanists include bacteria (now studied in bacteriology), fungi (mycology) – including lichen-forming fungi (lichenology), non-chlorophyte algae (phycology), and viruses (virology). However, attention is still given to these groups by botanists, and fungi (including lichens) and photosynthetic protists are usually covered in introductory botany courses. |
Paleobotanists study ancient plants in the fossil record to provide information about the evolutionary history of plants. Cyanobacteria, the first oxygen-releasing photosynthetic organisms on Earth, are thought to have given rise to the ancestor of plants by entering into an endosymbiotic relationship with an early eukaryote, ultimately becoming the chloroplasts in plant cells. The new photosynthetic plants (along with their algal relatives) accelerated the rise in atmospheric oxygen started by the cyanobacteria, changing the ancient oxygen-free, reducing, atmosphere to one in which free oxygen has been abundant for more than 2 billion years. |
Virtually all staple foods come either directly from primary production by plants, or indirectly from animals that eat them. Plants and other photosynthetic organisms are at the base of most 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 used by animals. This is what ecologists call the first trophic level. The modern forms of the major staple foods, such as maize, rice, wheat and other cereal grasses, pulses, bananas and plantains, as well as flax and cotton grown for their fibres, are the outcome of prehistoric selection over thousands of years from among wild ancestral plants with the most desirable characteristics. Botanists study how plants produce food and how to increase yields, for example through plant breeding, making their work important to mankind's ability to feed the world and provide food security for future generations. Botanists also study weeds, which are a considerable problem in agriculture, and the biology and control of plant pathogens in agriculture and natural ecosystems. Ethnobotany is the study of the relationships between plants and people. When applied to the investigation of historical plant–people relationships ethnobotany may be referred to as archaeobotany or palaeoethnobotany. |
Plants and various other groups of photosynthetic eukaryotes collectively known as "algae" have unique organelles known as chloroplasts. Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Chloroplasts and cyanobacteria contain the blue-green pigment chlorophyll a. Chlorophyll a (as well as its plant and green algal-specific cousin chlorophyll b)[a] absorbs light in the blue-violet and orange/red parts of the spectrum while reflecting and transmitting the green light that we see as the characteristic colour of these organisms. The energy in the red and blue light that these pigments absorb is used by chloroplasts to make energy-rich carbon compounds from carbon dioxide and water by oxygenic photosynthesis, a process that generates molecular oxygen (O2) as a by-product. |
The light energy captured by chlorophyll a is initially in the form of electrons (and later a proton gradient) that's used to make molecules of ATP and NADPH which temporarily store and transport energy. Their energy is used in the light-independent reactions of the Calvin cycle by the enzyme rubisco to produce molecules of the 3-carbon sugar glyceraldehyde 3-phosphate (G3P). Glyceraldehyde 3-phosphate is the first product of photosynthesis and the raw material from which glucose and almost all other organic molecules of biological origin are synthesized. Some of the glucose is converted to starch which is stored in the chloroplast. Starch is the characteristic energy store of most land plants and algae, while inulin, a polymer of fructose is used for the same purpose in the sunflower family Asteraceae. Some of the glucose is converted to sucrose (common table sugar) for export to the rest of the plant. |
Plants synthesize a number of unique polymers like the polysaccharide molecules cellulose, pectin and xyloglucan from which the land plant cell wall is constructed. Vascular land plants make lignin, a polymer used to strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when a plant sucks water through them under water stress. Lignin is also used in other cell types like sclerenchyma fibers that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in the fossil record. It is widely regarded as a marker for the start of land plant evolution during the Ordovician period. The concentration of carbon dioxide in the atmosphere today is much lower than it was when plants emerged onto land during the Ordovician and Silurian periods. Many monocots like maize and the pineapple and some dicots like the Asteraceae have since independently evolved pathways like Crassulacean acid metabolism and the C4 carbon fixation pathway for photosynthesis which avoid the losses resulting from photorespiration in the more common C3 carbon fixation pathway. These biochemical strategies are unique to land plants. |
Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism. Some of these compounds are toxins such as the alkaloid coniine from hemlock. Others, such as the essential oils peppermint oil and lemon oil are useful for their aroma, as flavourings and spices (e.g., capsaicin), and in medicine as pharmaceuticals as in opium from opium poppies. Many medicinal and recreational drugs, such as tetrahydrocannabinol (active ingredient in cannabis), caffeine, morphine and nicotine come directly from plants. Others are simple derivatives of botanical natural products. For example, the pain killer aspirin is the acetyl ester of salicylic acid, originally isolated from the bark of willow trees, and a wide range of opiate painkillers like heroin are obtained by chemical modification of morphine obtained from the opium poppy. Popular stimulants come from plants, such as caffeine from coffee, tea and chocolate, and nicotine from tobacco. Most alcoholic beverages come from fermentation of carbohydrate-rich plant products such as barley (beer), rice (sake) and grapes (wine). |
Sugar, starch, cotton, linen, hemp, some types of rope, wood and particle boards, papyrus and paper, vegetable oils, wax, and natural rubber are examples of commercially important materials made from plant tissues or their secondary products. Charcoal, a pure form of carbon made by pyrolysis of wood, has a long history as a metal-smelting fuel, as a filter material and adsorbent and as an artist's material and is one of the three ingredients of gunpowder. Cellulose, the world's most abundant organic polymer, can be converted into energy, fuels, materials and chemical feedstock. Products made from cellulose include rayon and cellophane, wallpaper paste, biobutanol and gun cotton. Sugarcane, rapeseed and soy are some of the plants with a highly fermentable sugar or oil content that are used as sources of biofuels, important alternatives to fossil fuels, such as biodiesel. |
Plant ecology is the science of the functional relationships between plants and their habitats—the environments where they complete their life cycles. Plant ecologists study the composition of local and regional floras, their biodiversity, genetic diversity and fitness, the adaptation of plants to their environment, and their competitive or mutualistic interactions with other species. The goals of plant ecology are to understand the causes of their distribution patterns, productivity, environmental impact, evolution, and responses to environmental change. |
Plants depend on certain edaphic (soil) and climatic factors in their environment but can modify these factors too. For example, they can change their environment's albedo, increase runoff interception, stabilize mineral soils and develop their organic content, and affect local temperature. Plants compete with other organisms in their ecosystem for resources. They interact with their neighbours at a variety of spatial scales in groups, populations and communities that collectively constitute vegetation. Regions with characteristic vegetation types and dominant plants as well as similar abiotic and biotic factors, climate, and geography make up biomes like tundra or tropical rainforest. |
Plant responses to climate and other environmental changes can inform our understanding of how these changes affect ecosystem function and productivity. For example, plant phenology can be a useful proxy for temperature in historical climatology, and the biological impact of climate change and global warming. Palynology, the analysis of fossil pollen deposits in sediments from thousands or millions of years ago allows the reconstruction of past climates. Estimates of atmospheric CO2 concentrations since the Palaeozoic have been obtained from stomatal densities and the leaf shapes and sizes of ancient land plants. Ozone depletion can expose plants to higher levels of ultraviolet radiation-B (UV-B), resulting in lower growth rates. Moreover, information from studies of community ecology, plant systematics, and taxonomy is essential to understanding vegetation change, habitat destruction and species extinction. |
Inheritance in plants follows the same fundamental principles of genetics as in other multicellular organisms. Gregor Mendel discovered the genetic laws of inheritance by studying inherited traits such as shape in Pisum sativum (peas). What Mendel learned from studying plants has had far reaching benefits outside of botany. Similarly, "jumping genes" were discovered by Barbara McClintock while she was studying maize. Nevertheless, there are some distinctive genetic differences between plants and other organisms. |
Species boundaries in plants may be weaker than in animals, and cross species hybrids are often possible. A familiar example is peppermint, Mentha × piperita, a sterile hybrid between Mentha aquatica and spearmint, Mentha spicata. The many cultivated varieties of wheat are the result of multiple inter- and intra-specific crosses between wild species and their hybrids. Angiosperms with monoecious flowers often have self-incompatibility mechanisms that operate between the pollen and stigma so that the pollen either fails to reach the stigma or fails to germinate and produce male gametes. This is one of several methods used by plants to promote outcrossing. In many land plants the male and female gametes are produced by separate individuals. These species are said to be dioecious when referring to vascular plant sporophytes and dioicous when referring to bryophyte gametophytes. |
Unlike in higher animals, where parthenogenesis is rare, asexual reproduction may occur in plants by several different mechanisms. The formation of stem tubers in potato is one example. Particularly in arctic or alpine habitats, where opportunities for fertilisation of flowers by animals are rare, plantlets or bulbs, may develop instead of flowers, replacing sexual reproduction with asexual reproduction and giving rise to clonal populations genetically identical to the parent. This is one of several types of apomixis that occur in plants. Apomixis can also happen in a seed, producing a seed that contains an embryo genetically identical to the parent. |
Most sexually reproducing organisms are diploid, with paired chromosomes, but doubling of their chromosome number may occur due to errors in cytokinesis. This can occur early in development to produce an autopolyploid or partly autopolyploid organism, or during normal processes of cellular differentiation to produce some cell types that are polyploid (endopolyploidy), or during gamete formation. An allopolyploid plant may result from a hybridisation event between two different species. Both autopolyploid and allopolyploid plants can often reproduce normally, but may be unable to cross-breed successfully with the parent population because there is a mismatch in chromosome numbers. These plants that are reproductively isolated from the parent species but live within the same geographical area, may be sufficiently successful to form a new species. Some otherwise sterile plant polyploids can still reproduce vegetatively or by seed apomixis, forming clonal populations of identical individuals. Durum wheat is a fertile tetraploid allopolyploid, while bread wheat is a fertile hexaploid. The commercial banana is an example of a sterile, seedless triploid hybrid. Common dandelion is a triploid that produces viable seeds by apomictic seed. |
A considerable amount of new knowledge about plant function comes from studies of the molecular genetics of model plants such as the Thale cress, Arabidopsis thaliana, a weedy species in the mustard family (Brassicaceae). The genome or hereditary information contained in the genes of this species is encoded by about 135 million base pairs of DNA, forming one of the smallest genomes among flowering plants. Arabidopsis was the first plant to have its genome sequenced, in 2000. The sequencing of some other relatively small genomes, of rice (Oryza sativa) and Brachypodium distachyon, has made them important model species for understanding the genetics, cellular and molecular biology of cereals, grasses and monocots generally. |
Model plants such as Arabidopsis thaliana are used for studying the molecular biology of plant cells and the chloroplast. Ideally, these organisms have small genomes that are well known or completely sequenced, small stature and short generation times. Corn has been used to study mechanisms of photosynthesis and phloem loading of sugar in C4 plants. The single celled green alga Chlamydomonas reinhardtii, while not an embryophyte itself, contains a green-pigmented chloroplast related to that of land plants, making it useful for study. A red alga Cyanidioschyzon merolae has also been used to study some basic chloroplast functions. Spinach, peas, soybeans and a moss Physcomitrella patens are commonly used to study plant cell biology. |
Agrobacterium tumefaciens, a soil rhizosphere bacterium, can attach to plant cells and infect them with a callus-inducing Ti plasmid by horizontal gene transfer, causing a callus infection called crown gall disease. Schell and Van Montagu (1977) hypothesised that the Ti plasmid could be a natural vector for introducing the Nif gene responsible for nitrogen fixation in the root nodules of legumes and other plant species. Today, genetic modification of the Ti plasmid is one of the main techniques for introduction of transgenes to plants and the creation of genetically modified crops. |
Epigenetics is the study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in the underlying DNA sequence but cause the organism's genes to behave (or "express themselves") differently. One example of epigenetic change is the marking of the genes by DNA methylation which determines whether they will be expressed or not. Gene expression can also be controlled by repressor proteins that attach to silencer regions of the DNA and prevent that region of the DNA code from being expressed. Epigenetic marks may be added or removed from the DNA during programmed stages of development of the plant, and are responsible, for example, for the differences between anthers, petals and normal leaves, despite the fact that they all have the same underlying genetic code. Epigenetic changes may be temporary or may remain through successive cell divisions for the remainder of the cell's life. Some epigenetic changes have been shown to be heritable, while others are reset in the germ cells. |
Epigenetic changes in eukaryotic biology serve to regulate the process of cellular differentiation. During morphogenesis, totipotent stem cells become the various pluripotent cell lines of the embryo, which in turn become fully differentiated cells. A single fertilized egg cell, the zygote, gives rise to the many different plant cell types including parenchyma, xylem vessel elements, phloem sieve tubes, guard cells of the epidermis, etc. as it continues to divide. The process results from the epigenetic activation of some genes and inhibition of others. |
Unlike animals, many plant cells, particularly those of the parenchyma, do not terminally differentiate, remaining totipotent with the ability to give rise to a new individual plant. Exceptions include highly lignified cells, the sclerenchyma and xylem which are dead at maturity, and the phloem sieve tubes which lack nuclei. While plants use many of the same epigenetic mechanisms as animals, such as chromatin remodeling, an alternative hypothesis is that plants set their gene expression patterns using positional information from the environment and surrounding cells to determine their developmental fate. |
The algae are a polyphyletic group and are placed in various divisions, some more closely related to plants than others. There are many differences between them in features such as cell wall composition, biochemistry, pigmentation, chloroplast structure and nutrient reserves. The algal division Charophyta, sister to the green algal division Chlorophyta, is considered to contain the ancestor of true plants. The Charophyte class Charophyceae and the land plant sub-kingdom Embryophyta together form the monophyletic group or clade Streptophytina. |
Nonvascular land plants are embryophytes that lack the vascular tissues xylem and phloem. They include mosses, liverworts and hornworts. Pteridophytic vascular plants with true xylem and phloem that reproduced by spores germinating into free-living gametophytes evolved during the Silurian period and diversified into several lineages during the late Silurian and early Devonian. Representatives of the lycopods have survived to the present day. By the end of the Devonian period, several groups, including the lycopods, sphenophylls and progymnosperms, had independently evolved "megaspory" – their spores were of two distinct sizes, larger megaspores and smaller microspores. Their reduced gametophytes developed from megaspores retained within the spore-producing organs (megasporangia) of the sporophyte, a condition known as endospory. Seeds consist of an endosporic megasporangium surrounded by one or two sheathing layers (integuments). The young sporophyte develops within the seed, which on germination splits to release it. The earliest known seed plants date from the latest Devonian Famennian stage. Following the evolution of the seed habit, seed plants diversified, giving rise to a number of now-extinct groups, including seed ferns, as well as the modern gymnosperms and angiosperms. Gymnosperms produce "naked seeds" not fully enclosed in an ovary; modern representatives include conifers, cycads, Ginkgo, and Gnetales. Angiosperms produce seeds enclosed in a structure such as a carpel or an ovary. Ongoing research on the molecular phylogenetics of living plants appears to show that the angiosperms are a sister clade to the gymnosperms. |
Plant physiology encompasses all the internal chemical and physical activities of plants associated with life. Chemicals obtained from the air, soil and water form the basis of all plant metabolism. The energy of sunlight, captured by oxygenic photosynthesis and released by cellular respiration, is the basis of almost all life. Photoautotrophs, including all green plants, algae and cyanobacteria gather energy directly from sunlight by photosynthesis. Heterotrophs including all animals, all fungi, all completely parasitic plants, and non-photosynthetic bacteria take in organic molecules produced by photoautotrophs and respire them or use them in the construction of cells and tissues. Respiration is the oxidation of carbon compounds by breaking them down into simpler structures to release the energy they contain, essentially the opposite of photosynthesis. |
Molecules are moved within plants by transport processes that operate at a variety of spatial scales. Subcellular transport of ions, electrons and molecules such as water and enzymes occurs across cell membranes. Minerals and water are transported from roots to other parts of the plant in the transpiration stream. Diffusion, osmosis, and active transport and mass flow are all different ways transport can occur. Examples of elements that plants need to transport are nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur. In vascular plants, these elements are extracted from the soil as soluble ions by the roots and transported throughout the plant in the xylem. Most of the elements required for plant nutrition come from the chemical breakdown of soil minerals. Sucrose produced by photosynthesis is transported from the leaves to other parts of the plant in the phloem and plant hormones are transported by a variety of processes. |
The hypothesis that plant growth and development is coordinated by plant hormones or plant growth regulators first emerged in the late 19th century. Darwin experimented on the movements of plant shoots and roots towards light and gravity, and concluded "It is hardly an exaggeration to say that the tip of the radicle . . acts like the brain of one of the lower animals . . directing the several movements". About the same time, the role of auxins (from the Greek auxein, to grow) in control of plant growth was first outlined by the Dutch scientist Frits Went. The first known auxin, indole-3-acetic acid (IAA), which promotes cell growth, was only isolated from plants about 50 years later. This compound mediates the tropic responses of shoots and roots towards light and gravity. The finding in 1939 that plant callus could be maintained in culture containing IAA, followed by the observation in 1947 that it could be induced to form roots and shoots by controlling the concentration of growth hormones were key steps in the development of plant biotechnology and genetic modification. |
Cytokinins are a class of plant hormones named for their control of cell division or cytokinesis. The natural cytokinin zeatin was discovered in corn, Zea mays, and is a derivative of the purine adenine. Zeatin is produced in roots and transported to shoots in the xylem where it promotes cell division, bud development, and the greening of chloroplasts. The gibberelins, such as Gibberelic acid are diterpenes synthesised from acetyl CoA via the mevalonate pathway. They are involved in the promotion of germination and dormancy-breaking in seeds, in regulation of plant height by controlling stem elongation and the control of flowering. Abscisic acid (ABA) occurs in all land plants except liverworts, and is synthesised from carotenoids in the chloroplasts and other plastids. It inhibits cell division, promotes seed maturation, and dormancy, and promotes stomatal closure. It was so named because it was originally thought to control abscission. Ethylene is a gaseous hormone that is produced in all higher plant tissues from methionine. It is now known to be the hormone that stimulates or regulates fruit ripening and abscission, and it, or the synthetic growth regulator ethephon which is rapidly metabolised to produce ethylene, are used on industrial scale to promote ripening of cotton, pineapples and other climacteric crops. |
Plant anatomy is the study of the structure of plant cells and tissues, whereas plant morphology is the study of their external form. All plants are multicellular eukaryotes, their DNA stored in nuclei. The characteristic features of plant cells that distinguish them from those of animals and fungi include a primary cell wall composed of the polysaccharides cellulose, hemicellulose and pectin, larger vacuoles than in animal cells and the presence of plastids with unique photosynthetic and biosynthetic functions as in the chloroplasts. Other plastids contain storage products such as starch (amyloplasts) or lipids (elaioplasts). Uniquely, streptophyte cells and those of the green algal order Trentepohliales divide by construction of a phragmoplast as a template for building a cell plate late in cell division. |
The bodies of vascular plants including clubmosses, ferns and seed plants (gymnosperms and angiosperms) generally have aerial and subterranean subsystems. The shoots consist of stems bearing green photosynthesising leaves and reproductive structures. The underground vascularised roots bear root hairs at their tips and generally lack chlorophyll. Non-vascular plants, the liverworts, hornworts and mosses do not produce ground-penetrating vascular roots and most of the plant participates in photosynthesis. The sporophyte generation is nonphotosynthetic in liverworts but may be able to contribute part of its energy needs by photosynthesis in mosses and hornworts. |
The root system and the shoot system are interdependent – the usually nonphotosynthetic root system depends on the shoot system for food, and the usually photosynthetic shoot system depends on water and minerals from the root system. Cells in each system are capable of creating cells of the other and producing adventitious shoots or roots. Stolons and tubers are examples of shoots that can grow roots. Roots that spread out close to the surface, such as those of willows, can produce shoots and ultimately new plants. In the event that one of the systems is lost, the other can often regrow it. In fact it is possible to grow an entire plant from a single leaf, as is the case with Saintpaulia, or even a single cell – which can dedifferentiate into a callus (a mass of unspecialised cells) that can grow into a new plant. In vascular plants, the xylem and phloem are the conductive tissues that transport resources between shoots and roots. Roots are often adapted to store food such as sugars or starch, as in sugar beets and carrots. |
Stems mainly provide support to the leaves and reproductive structures, but can store water in succulent plants such as cacti, food as in potato tubers, or reproduce vegetatively as in the stolons of strawberry plants or in the process of layering. Leaves gather sunlight and carry out photosynthesis. Large, flat, flexible, green leaves are called foliage leaves. Gymnosperms, such as conifers, cycads, Ginkgo, and gnetophytes are seed-producing plants with open seeds. Angiosperms are seed-producing plants that produce flowers and have enclosed seeds. Woody plants, such as azaleas and oaks, undergo a secondary growth phase resulting in two additional types of tissues: wood (secondary xylem) and bark (secondary phloem and cork). All gymnosperms and many angiosperms are woody plants. Some plants reproduce sexually, some asexually, and some via both means. |
Systematic botany is part of systematic biology, which is concerned with the range and diversity of organisms and their relationships, particularly as determined by their evolutionary history. It involves, or is related to, biological classification, scientific taxonomy and phylogenetics. Biological classification is the method by which botanists group organisms into categories such as genera or species. Biological classification is a form of scientific taxonomy. Modern taxonomy is rooted in the work of Carl Linnaeus, who grouped species according to shared physical characteristics. These groupings have since been revised to align better with the Darwinian principle of common descent – grouping organisms by ancestry rather than superficial characteristics. While scientists do not always agree on how to classify organisms, molecular phylogenetics, which uses DNA sequences as data, has driven many recent revisions along evolutionary lines and is likely to continue to do so. The dominant classification system is called Linnaean taxonomy. It includes ranks and binomial nomenclature. The nomenclature of botanical organisms is codified in the International Code of Nomenclature for algae, fungi, and plants (ICN) and administered by the International Botanical Congress. |
Kingdom Plantae belongs to Domain Eukarya and is broken down recursively until each species is separately classified. The order is: Kingdom; Phylum (or Division); Class; Order; Family; Genus (plural genera); Species. The scientific name of a plant represents its genus and its species within the genus, resulting in a single world-wide name for each organism. For example, the tiger lily is Lilium columbianum. Lilium is the genus, and columbianum the specific epithet. The combination is the name of the species. When writing the scientific name of an organism, it is proper to capitalise the first letter in the genus and put all of the specific epithet in lowercase. Additionally, the entire term is ordinarily italicised (or underlined when italics are not available). |
The evolutionary relationships and heredity of a group of organisms is called its phylogeny. Phylogenetic studies attempt to discover phylogenies. The basic approach is to use similarities based on shared inheritance to determine relationships. As an example, species of Pereskia are trees or bushes with prominent leaves. They do not obviously resemble a typical leafless cactus such as an Echinocactus. However, both Pereskia and Echinocactus have spines produced from areoles (highly specialised pad-like structures) suggesting that the two genera are indeed related. |
Judging relationships based on shared characters requires care, since plants may resemble one another through convergent evolution in which characters have arisen independently. Some euphorbias have leafless, rounded bodies adapted to water conservation similar to those of globular cacti, but characters such as the structure of their flowers make it clear that the two groups are not closely related. The cladistic method takes a systematic approach to characters, distinguishing between those that carry no information about shared evolutionary history – such as those evolved separately in different groups (homoplasies) or those left over from ancestors (plesiomorphies) – and derived characters, which have been passed down from innovations in a shared ancestor (apomorphies). Only derived characters, such as the spine-producing areoles of cacti, provide evidence for descent from a common ancestor. The results of cladistic analyses are expressed as cladograms: tree-like diagrams showing the pattern of evolutionary branching and descent. |
From the 1990s onwards, the predominant approach to constructing phylogenies for living plants has been molecular phylogenetics, which uses molecular characters, particularly DNA sequences, rather than morphological characters like the presence or absence of spines and areoles. The difference is that the genetic code itself is used to decide evolutionary relationships, instead of being used indirectly via the characters it gives rise to. Clive Stace describes this as having "direct access to the genetic basis of evolution." As a simple example, prior to the use of genetic evidence, fungi were thought either to be plants or to be more closely related to plants than animals. Genetic evidence suggests that the true evolutionary relationship of multicelled organisms is as shown in the cladogram below – fungi are more closely related to animals than to plants. |
In 1998 the Angiosperm Phylogeny Group published a phylogeny for flowering plants based on an analysis of DNA sequences from most families of flowering plants. As a result of this work, many questions, such as which families represent the earliest branches of angiosperms, have now been answered. Investigating how plant species are related to each other allows botanists to better understand the process of evolution in plants. Despite the study of model plants and increasing use of DNA evidence, there is ongoing work and discussion among taxonomists about how best to classify plants into various taxa. Technological developments such as computers and electron microscopes have greatly increased the level of detail studied and speed at which data can be analysed. |
Madonna Louise Ciccone (/tʃɪˈkoʊni/; Italian: [tʃikˈkoːne]; born August 16, 1958) is an American singer, songwriter, actress, and businesswoman. She achieved popularity by pushing the boundaries of lyrical content in mainstream popular music and imagery in her music videos, which became a fixture on MTV. Madonna is known for reinventing both her music and image, and for maintaining her autonomy within the recording industry. Music critics have acclaimed her musical productions, which have generated some controversy. Often referred to as the "Queen of Pop", she is often cited as an influence by other artists. |
Born in Bay City, Michigan, Madonna moved to New York City in 1977 to pursue a career in modern dance. After performing in the music groups Breakfast Club and Emmy, she signed with Sire Records (an auxiliary label of Warner Bros. Records) in 1982 and released her self-titled debut album the following year. She followed it with a series of commercially and critcally successful albums, including the Grammy Award winners Ray of Light (1998) and Confessions on a Dance Floor (2005). Throughout her career, Madonna has written and produced most of her songs, with many of them reaching number one on the record charts, including "Like a Virgin", "Into the Groove", "Papa Don't Preach", "Like a Prayer", "Vogue", "Frozen", "Music", "Hung Up", and "4 Minutes". |
Madonna's popularity was further enhanced by her film roles, including Desperately Seeking Susan (1985), Dick Tracy (1990), and Evita (1996); the latter earned her a Golden Globe Award for Best Actress. However, most of her other films have been panned by critics. Her other ventures include fashion design, writing children's books, and filmmaking. She has been acclaimed as a businesswoman, particularly after she founded entertainment company Maverick (including the label Maverick Records). In 2007 she signed an unprecedented US $120 million 360 deal with Live Nation. |
Having sold more than 300 million records worldwide, Madonna is recognized as the best-selling female recording artist of all time by Guinness World Records. The Recording Industry Association of America (RIAA) listed her as the best-selling female rock artist of the 20th century and the second best-selling female artist in the United States, with 64.5 million certified albums. According to Billboard, Madonna is the highest-grossing solo touring artist of all time, earning US $1.31 billion from her concerts since 1990. She was ranked at number two, behind only The Beatles, on the Billboard Hot 100 All-Time Top Artists, making her the most successful solo artist in the history of American singles chart. Madonna became one of the five founding members of the UK Music Hall of Fame and was inducted into the Rock and Roll Hall of Fame in her first year of eligibility. |
Madonna was born to Catholic parents Silvio Anthony "Tony" Ciccone (b. 1931) and Madonna Louise Fortin (c. 1933 – December 1, 1963) in Bay City, Michigan, on August 16, 1958. Her father's parents were immigrants from Pacentro, Italy, while her mother was of French-Canadian ancestry. Tony worked as an engineer designer for Chrysler and General Motors. Since Madonna had the same name as her mother, family members called her "Little Nonni". She has two elder brothers, Anthony (born 1956) and Martin (born 1957), and three younger siblings, Paula (born 1959), Christopher (born 1960), and Melanie (born 1962). |
Upon being confirmed in 1966, she adopted Veronica as a confirmation name. She was raised in the Detroit suburbs of Pontiac and Avon Township (now Rochester Hills). Months before her mother died of breast cancer, Madonna noticed changes in her behavior and personality, although she did not understand the reason. Her mother was at a loss to explain her medical condition, and often began to cry when Madonna questioned her about it. Madonna later acknowledged that she had not grasped the concept of her mother dying. |
Madonna turned to her paternal grandmother for solace. The Ciccone siblings resented housekeepers and invariably rebelled against anyone brought into their home ostensibly to take the place of their beloved mother. Madonna later told Vanity Fair that she saw herself in her youth as a "lonely girl who was searching for something. I wasn't rebellious in a certain way. I cared about being good at something. I didn't shave my underarms and I didn't wear make-up like normal girls do. But I studied and I got good grades.... I wanted to be somebody." Terrified that her father Tony could be taken from her as well, Madonna was often unable to sleep unless she was near him. |
In 1966, Tony married the family's housekeeper Joan Gustafson; they had two children, Jennifer (born 1967) and Mario (born 1968). At this point, Madonna started to resent him for decades, and developed a rebellious attitude. She attended St. Frederick's and St. Andrew's Catholic Elementary Schools, and West Middle School. Madonna was known for her high grade point average, and achieved notoriety for her unconventional behavior. She would perform cartwheels and handstands in the hallways between classes, dangle by her knees from the monkey bars during recess, and pull up her skirt during class—all so that the boys could see her underwear. |
In 1978, she dropped out of college and relocated to New York City. She had little money and worked as a waitress at Dunkin' Donuts and with modern dance troupes, taking classes at the Alvin Ailey American Dance Theater and eventually performing with Pear Lang Dance Theater. Madonna said of her move to New York, "It was the first time I'd ever taken a plane, the first time I'd ever gotten a taxi cab. I came here with $35 in my pocket. It was the bravest thing I'd ever done." She started to work as a backup dancer for other established artists. Madonna claimed that during a late night she was returning from a rehearsal, when a pair of men held her at knifepoint and forced her to perform fellatio. Madonna later commented that "the episode was a taste of my weakness, it showed me that I still could not save myself in spite of all the strong-girl show. I could never forget it." |
While performing as a backup singer and dancer for the French disco artist Patrick Hernandez on his 1979 world tour, Madonna became romantically involved with musician Dan Gilroy. Together, they formed her first rock band, the Breakfast Club, for which Madonna sang and played drums and guitar. In 1980 or 1981 she left Breakfast Club and, with her former boyfriend Stephen Bray as drummer, formed the band Emmy. The two began writing songs together, and Madonna later decided to market herself as a solo act. Their music impressed DJ and record producer Mark Kamins who arranged a meeting between Madonna and Sire Records founder Seymour Stein. |
After Madonna signed a singles deal with Sire, her debut single, "Everybody", was released in October 1982, and the second, "Burning Up", in March 1983. Both became big club hits in the United States, reaching number three on Hot Dance Club Songs chart compiled by Billboard magazine. After this success, she started developing her debut album, Madonna, which was primarily produced by Reggie Lucas of Warner Bros. However, she was not happy with the completed tracks and disagreed with Lucas' production techniques, so decided to seek additional help. |
Madonna moved in with boyfriend John "Jellybean" Benitez, asking his help for finishing the album's production. Benitez remixed most of the tracks and produced "Holiday", which was her third single and her first global hit. The overall sound of Madonna was dissonant and in the form of upbeat synthetic disco, using some of the new technology of the time, like the Linn drum machine, Moog bass and the OB-X synthesizer. The album was released in July 1983 and peaked at number eight on the Billboard 200 six months later, in 1984. It yielded two more hit singles, "Borderline" and "Lucky Star". |
Madonna's look and style of dressing, her performances, and her music videos influenced young girls and women. Her style became one of the female fashion trends of the 1980s. Created by stylist and jewelry designer Maripol, the look consisted of lace tops, skirts over capri pants, fishnet stockings, jewelry bearing the crucifix, bracelets, and bleached hair. Madonna achieved global recognition after the release of her second studio album, Like a Virgin, in November 1984. It topped the charts in several countries and became her first number one album on the Billboard 200. The title track, "Like a Virgin", topped the Billboard Hot 100 chart for six consecutive weeks. It attracted the attention of organizations who complained that the song and its accompanying video promoted premarital sex and undermined family values, and moralists sought to have the song and video banned. |
Madonna was criticized for her performance of "Like a Virgin" at the first 1984 MTV Video Music Awards (VMA). She appeared on stage atop a giant wedding cake, wearing a wedding dress and white gloves. The performance is noted by MTV as an iconic moment in VMA history. In later years, Madonna commented that she was terrified of the performance. The next hit was "Material Girl" promoted by her video, a mimicry of Marilyn Monroe's performance of the song "Diamonds Are a Girl's Best Friend" from the 1953 film Gentlemen Prefer Blondes. While filming this video, Madonna started dating actor Sean Penn. They married on her birthday in 1985. Like a Virgin was certified diamond by the Recording Industry Association of America and sold more than 25 million copies worldwide. In February 1984, according to the film director Sir Richard Attenborough, Madonna auditioned at the Royale Theatre on Broadway for a dance role in his movie version of A Chorus Line using her birth-name of Ciccone, but he rejected her. |
Madonna entered mainstream films in February 1985, beginning with a brief appearance as a club singer in Vision Quest, a romantic drama film. Its soundtrack contained two new singles, her U.S. number-one single, "Crazy for You" and "Gambler". She also appeared in the comedy Desperately Seeking Susan in March 1985, a film which introduced the song "Into the Groove", her first number one single in the United Kingdom. Although Madonna was not the lead actress for the film, her profile was such that the movie widely became considered (and marketed) as a Madonna vehicle. The New York Times film critic Vincent Canby named it one of the ten best films of 1985. |
Beginning in April 1985, Madonna embarked on her first concert tour in North America, The Virgin Tour, with the Beastie Boys as her opening act. She progressed from playing CBGB and the Mudd Club to playing large sporting arenas. At that time she released two more hit singles from the album, "Angel" and "Dress You Up". In July, Penthouse and Playboy magazines published a number of nude photos of Madonna, taken in New York in 1978. She had posed for the photographs as she needed money at the time, and was paid as little as $25 a session. The publication of the photos caused a media uproar, but Madonna remained "unapologetic and defiant". The photographs were ultimately sold for up to $100,000. She referred to these events at the 1985 outdoor Live Aid charity concert, saying that she would not take her jacket off because "[the media] might hold it against me ten years from now." |
In June 1986, Madonna released her third studio album, True Blue, which was inspired by and dedicated to Sean Penn. Rolling Stone magazine was generally impressed with the effort, writing that the album "sound[s] as if it comes from the heart". It resulted in three singles making it to number-one on the Billboard Hot 100: "Live to Tell", "Papa Don't Preach" and "Open Your Heart", and two more top-five singles: "True Blue" and "La Isla Bonita". The album topped the charts in over 28 countries worldwide, an unprecedented achievement at the time, and became her best-selling studio album of her career to this date with sales of 25 million. In the same year, Madonna starred in the critically panned film Shanghai Surprise, for which she was awarded the Golden Raspberry Award for "worst actress". She made her theatrical debut in a production of David Rabe's Goose and Tom-Tom; the film and play both co-starred Penn. The next year, Madonna was featured in the film Who's That Girl. She contributed four songs to its soundtrack, including the title track and "Causing a Commotion". |
In January 1989, Madonna signed an endorsement deal with soft-drink manufacturer, Pepsi. In one of her Pepsi commercials, she debuted her song "Like a Prayer". The corresponding music video featured many Catholic symbols such as stigmata and cross burning, and a dream of making love to a saint, leading the Vatican to condemn the video. Religious groups sought to ban the commercial and boycott Pepsi products. Pepsi revoked the commercial and canceled her sponsorship contract. The song was included on Madonna's fourth studio album, Like a Prayer, which was co-written and co-produced by Patrick Leonard and Stephen Bray. Madonna received positive feedback for the album, with Rolling Stone writing that it was "as close to art as pop music gets". Like a Prayer peaked at number one on the Billboard 200 and sold 15 million copies worldwide, with 4 million copies sold in the U.S. alone. Six singles were released from the album, including "Like a Prayer", which reached number one, and "Express Yourself" and "Cherish", both peaking at number two. By the end of the 1980s, Madonna was named as the "Artist of the Decade" by MTV, Billboard and Musician magazine. |
Madonna starred as Breathless Mahoney in the film Dick Tracy (1990), with Warren Beatty playing the title role. Her performance led to a Saturn Award nomination for Best Actress. To accompany the film, she released the soundtrack album, I'm Breathless, which included songs inspired by the film's 1930s setting. It also featured the US number-one hit "Vogue" and "Sooner or Later", which earned songwriter Stephen Sondheim an Academy Award for Best Original Song in 1991. While shooting the film, Madonna began a relationship with Beatty, which dissolved by the end of 1990. In April 1990, Madonna began her Blond Ambition World Tour, which was held until August. Rolling Stone called it an "elaborately choreographed, sexually provocative extravaganza" and proclaimed it "the best tour of 1990". The tour generated strong negative reaction from religious groups for her performance of "Like a Virgin", during which two male dancers caressed her body before she simulated masturbation. In response, Madonna said, "The tour in no way hurts anybody's sentiments. It's for open minds and gets them to see sexuality in a different way. Their own and others". The Laserdisc release of the tour won Madonna a Grammy Award in 1992 for Best Long Form Music Video. |
The Immaculate Collection, Madonna's first greatest-hits compilation album, was released in November 1990. It included two new songs, "Justify My Love" and "Rescue Me". The album was certified diamond by RIAA and sold over 30 million copies worldwide, becoming the best-selling compilation album by a solo artist in history. "Justify My Love" reached number one in the U.S. and top ten worldwide. Its music video featured scenes of sadomasochism, bondage, same-sex kissing, and brief nudity. The video was deemed too sexually explicit for MTV and was banned from the network. Madonna responded to the banning: "Why is it that people are willing to go and watch a movie about someone getting blown to bits for no reason at all, and nobody wants to see two girls kissing and two men snuggling?" |
In 1992, Madonna had a role in A League of Their Own as Mae Mordabito, a baseball player on an all-women's team. She recorded the film's theme song, "This Used to Be My Playground", which became a Hot 100 number one hit. The same year, she founded her own entertainment company, Maverick, consisting of a record company (Maverick Records), a film production company (Maverick Films), and associated music publishing, television broadcasting, book publishing and merchandising divisions. The deal was a joint venture with Time Warner and paid Madonna an advance of $60 million. It gave her 20% royalties from the music proceedings, one of the highest rates in the industry, equaled at that time only by Michael Jackson's royalty rate established a year earlier with Sony. The first release from the venture was Madonna's book, titled Sex. It consisted of sexually provocative and explicit images, photographed by Steven Meisel. The book received strong negative reaction from the media and the general public, but sold 1.5 million copies at $50 each in a matter of days. At the same time she released her fifth studio album, Erotica, which debuted at number two on the Billboard 200. Its title track peaked at number three on the Billboard Hot 100. Erotica also produced five singles: "Deeper and Deeper", "Bad Girl", "Fever", "Rain" and "Bye Bye Baby". Madonna had provocative imagery featured in the erotic thriller, Body of Evidence, a film which contained scenes of sadomasochism and bondage. It was poorly received by critics. She also starred in the film Dangerous Game, which was released straight to video in North America. The New York Times described the film as "angry and painful, and the pain feels real." |
In September 1993, Madonna embarked on The Girlie Show World Tour, in which she dressed as a whip-cracking dominatrix surrounded by topless dancers. In Puerto Rico she rubbed the island's flag between her legs on stage, resulting in outrage among the audience. In March 1994, she appeared as a guest on the Late Show with David Letterman, using profanity that required censorship on television, and handing Letterman a pair of her panties and asking him to smell it. The releases of her sexually explicit films, albums and book, and the aggressive appearance on Letterman all made critics question Madonna as a sexual renegade. Critics and fans reacted negatively, who commented that "she had gone too far" and that her career was over. |
Biographer J. Randy Taraborrelli described her ballad "I'll Remember" (1994) as an attempt to tone down her provocative image. The song was recorded for Alek Keshishian's film With Honors. She made a subdued appearance with Letterman at an awards show and appeared on The Tonight Show with Jay Leno after realizing that she needed to change her musical direction in order to sustain her popularity. With her sixth studio album, Bedtime Stories (1994), Madonna employed a softer image to try to improve the public perception. The album debuted at number three on the Billboard 200 and produced four singles, including "Secret" and "Take a Bow", the latter topping the Hot 100 for seven weeks, the longest period of any Madonna single. At the same time, she became romantically involved with fitness trainer Carlos Leon. Something to Remember, a collection of ballads, was released in November 1995. The album featured three new songs: "You'll See", "One More Chance", and a cover of Marvin Gaye's "I Want You". |
In Evita (1996), Madonna played the title role of Eva Perón. For a long time, Madonna had desired to play Perón and wrote to director Alan Parker to explain why she would be perfect for the part. She said later, "This is the role I was born to play. I put everything of me into this because it was much more than a role in a movie. It was exhilarating and intimidating at the same time..... And I am prouder of Evita than anything else I have done." After securing the role, she had vocal training and learned about the history of Argentina and Perón. During shooting she became ill several times due to the intense emotional effort required. However, as she told Oprah, she was also pregnant during the filming: "I was winded after every take. I had to lie on the couch every ten minutes so I could recover from dizzy spells, I was worried that I was shaking the baby around too much and that would injure it in some way." Madonna wrote in her personal diary at the time: "Ironically, this feeling of vulnerability and weakness is helping me in the movie. I'm sure Evita felt this way every day of her life once she discovered she was ill." |
After its release, Evita garnered critical appreciation. Zach Conner from Time magazine commented, "It's a relief to say that Evita is pretty damn fine, well cast and handsomely visualized. Madonna once again confounds our expectations. She plays Evita with a poignant weariness and has more than just a bit of star quality. Love or hate Madonna-Eva, she is a magnet for all eyes." Madonna won a Golden Globe Award for Best Actress in Motion Picture Musical or Comedy for the role. She released three singles from the Evita soundtrack album, including "You Must Love Me" (which won an Academy Award for Best Original Song in 1997) and "Don't Cry for Me Argentina". Madonna was later presented with the Artist Achievement Award by Tony Bennett at the 1996 Billboard Music Awards. On October 14, 1996, Madonna gave birth to Lourdes Maria Ciccone Leon, her daughter with Leon. Biographer Mary Cross writes that although Madonna was often ill during the filming and worried that her pregnancy would harm the film, she reached some important personal goals: "Now 38 years old, Madonna had at last triumphed on screen and achieved her dream of having a child, both in the same year. She had reached another turning point in her career, reinventing herself and her image with the public." Her relationship with Carlos Leon ended in May 1997; she declared that they were "better off as best friends." After Lourdes' birth, Madonna became involved in Eastern mysticism and Kabbalah. She was introduced to Jewish mysticism by actress Sandra Bernhard in 1997. |
Madonna's seventh studio album, Ray of Light, (1998) reflected a change in her image. She collaborated with electronica producer William Orbit and wanted to create a sound that could blend dance music with pop and British rock. American music critic Ann Powers explained that what Madonna searched for with Orbit "was a kind of a lushness that she wanted for this record. Techno and rave was happening in the 90's and had a lot of different forms. There was very experimental, more hard stuff like Aphex Twin. There was party stuff like Fatboy Slim. That's not what Madonna wanted for this. She wanted something more like a singer-songwriter, really. And William Orbit provided her with that." |
The album garnered critical acclaim. Ray of Light was honored with four Grammy Awards. In 2003, Slant Magazine called it "one of the great pop masterpieces of the '90s" and Rolling Stone listed it among "The 500 Greatest Albums of All Time". Commercially, the album peaked at number one in numerous countries and sold more than 16 million copies worldwide. The album's first single, "Frozen", became Madonna's first single to debut at number one in the UK, while in the U.S. it became her sixth number-two single, setting another record for Madonna as the artist with the most number two hits. The second single, "Ray of Light", debuted at number five on the Billboard Hot 100. |
The 1998 edition of Guinness Book of World Records stated: "No female artist has sold more records than Madonna around the world". In 1999 Madonna signed to play a violin teacher in the film Music of the Heart but left the project, citing "creative differences" with director Wes Craven. She recorded the single "Beautiful Stranger" for the 1999 film Austin Powers: The Spy Who Shagged Me. It reached number 19 on the Hot 100 solely on radio airplay. Madonna won a Grammy Award for "Best Song Written for a Motion Picture, Television or Other Visual Media". |
In 2000, Madonna starred in the film The Next Best Thing, and contributed two songs to the film's soundtrack; "Time Stood Still" and a cover of Don McLean's 1971 song "American Pie". She released her eighth studio album, Music, in September 2000. It featured elements from the electronica-inspired Ray of Light era, and like its predecessor, received acclaim from critics. Collaborating with French producer Mirwais Ahmadzaï, Madonna commented: "I love to work with the weirdos that no one knows about—the people who have raw talent and who are making music unlike anyone else out there. Music is the future of sound." Stephen Thomas Erlewine from AllMusic felt that "Music blows by in a kaleidoscopic rush of color, technique, style and substance. It has so many depth and layers that it's easily as self-aware and earnest as Ray of Light." The album took the number-one position in more than 20 countries worldwide and sold four million copies in the first ten days. In the U.S., Music debuted at the top, and became her first number-one album in eleven years since Like a Prayer. It produced three singles: the Hot 100 number one "Music", "Don't Tell Me", and "What It Feels Like for a Girl". The music video of "What It Feels Like for a Girl" depicted Madonna committing acts of crime and vandalism, and was banned by MTV and VH1. |
She met director Guy Ritchie, who would become her second husband, in November 1998 and gave birth to their son Rocco John Ritchie on August 11, 2000 in Los Angeles. Rocco and Madonna suffered complications from the birth due to her experiencing placenta praevia. He was christened at Dornoch Cathedral in Dornoch, Scotland, on December 21, 2000. Madonna married Ritchie the following day at nearby Skibo Castle. Her fifth concert tour, titled Drowned World Tour, started in June 2001. The tour visited cities in the U.S. and Europe and was the highest-grossing concert tour of the year by a solo artist, earning $75 million from 47 sold-out shows. She also released her second greatest-hits collection, titled GHV2, to coincide with the home video release of the tour. GHV2 debuted at number seven on the Billboard 200. |
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