153-533: See text. Sand dollars (also known as sea cookies or snapper biscuits in New Zealand and Brazil , or pansy shells in South Africa ) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida . Some species within the order, not quite as flat, are known as sea biscuits . Sand dollars can also be called "sand cakes" or "cake urchins". The term "sand dollar" derives from
306-557: A minority government can be formed if support from other parties during confidence and supply votes is assured. The governor-general appoints ministers under advice from the prime minister, who is by convention the parliamentary leader of the governing party or coalition. Cabinet , formed by ministers and led by the prime minister, is the highest policy-making body in government and responsible for deciding significant government actions. Members of Cabinet make major decisions collectively and are therefore collectively responsible for
459-471: A protectionist and highly regulated economy to a liberalised free-trade economy. Unemployment peaked just above 10% in 1991 and 1992, following the 1987 share market crash , but eventually fell to 3.7% in 2007 (ranking third from twenty-seven comparable OECD nations). However, the global financial crisis that followed had a major effect on New Zealand, with the GDP shrinking for five consecutive quarters,
612-427: A test . The test consists of calcium carbonate plates arranged in a fivefold symmetric pattern. The test of certain species of sand dollar have slits called lunules that can help the animal stay embedded in the sand to stop it from being swept away by an ocean wave. In living individuals, the test is covered by a skin of velvet -textured spines which are covered with very small hairs ( cilia ). Coordinated movements of
765-677: A day were similar, but at springs the tides rose 7 feet (2.1 m) in the morning but 9 feet (2.7 m) in the evening. Pierre-Simon Laplace formulated a system of partial differential equations relating the ocean's horizontal flow to its surface height, the first major dynamic theory for water tides. The Laplace tidal equations are still in use today. William Thomson, 1st Baron Kelvin , rewrote Laplace's equations in terms of vorticity which allowed for solutions describing tidally driven coastally trapped waves, known as Kelvin waves . Others including Kelvin and Henri Poincaré further developed Laplace's theory. Based on these developments and
918-523: A few days after (or before) new and full moon and are highest around the equinoxes, though Pliny noted many relationships now regarded as fanciful. In his Geography , Strabo described tides in the Persian Gulf having their greatest range when the moon was furthest from the plane of the Equator. All this despite the relatively small amplitude of Mediterranean basin tides. (The strong currents through
1071-632: A five-petaled garden flower . The Caribbean sand dollar or inflated sea biscuit, Clypeaster rosaceus , is thicker in height than most. In Spanish-speaking areas of the Americas, the sand dollar is most often known as galleta de mar (sea cookie ); the translated term is often encountered in English. In the folklore of Georgia in the United States, sand dollars were believed to represent coins lost by mermaids . Sand dollars diverged from
1224-505: A given day are typically not the same height (the daily inequality); these are the higher high water and the lower high water in tide tables . Similarly, the two low waters each day are the higher low water and the lower low water . The daily inequality is not consistent and is generally small when the Moon is over the Equator . The following reference tide levels can be defined, from
1377-506: A high level of innovation . Poverty in New Zealand is characterised by growing income inequality; wealth in New Zealand is highly concentrated , with the top 1% of the population owning 16% of the country's wealth, and the richest 5% owning 38%, leaving a stark contrast where half the population, including state beneficiaries and pensioners, receive less than $ 24,000. Moreover, child poverty in New Zealand has been identified by
1530-785: A party must win at least one electorate or 5% of the total party vote before it is eligible for a seat. Elections since the 1930s have been dominated by two political parties , National and Labour . More parties have been represented in Parliament since the introduction of MMP. New Zealand's judiciary , headed by the chief justice , includes the Supreme Court , Court of Appeal , the High Court , and subordinate courts. Judges and judicial officers are appointed non-politically and under strict rules regarding tenure to help maintain judicial independence . This theoretically allows
1683-540: A process they use to asexually clone themselves when sensing danger. The cloning process can take up to 24 hours and creates larvae that are 2/3 smaller than their original size which can help conceal them from the predator. The larvae of these sand dollars clone themselves when they sense dissolved mucus from a predatory fish. The larvae exposed to this mucus from the predatory fish respond to the threat by cloning themselves. This process doubles their population and halves their size which allows them to better escape detection by
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#17327935438601836-400: A series of conflicts between the colonial government and Māori tribes resulted in the alienation and confiscation of large amounts of Māori land. New Zealand became a dominion in 1907; it gained full statutory independence in 1947, retaining the monarch as head of state . Today, the majority of New Zealand's population of 5.25 million is of European descent ; the indigenous Māori are
1989-599: A similar trend to dairy, the number of vineyards doubling over the same period, overtaking wool exports for the first time in 2007. Low tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun ) and are also caused by the Earth and Moon orbiting one another. Tide tables can be used for any given locale to find
2142-516: A smooth sphere covered by a sufficiently deep ocean under the tidal force of a single deforming body is a prolate spheroid (essentially a three-dimensional oval) with major axis directed toward the deforming body. Maclaurin was the first to write about the Earth's rotational effects on motion. Euler realized that the tidal force's horizontal component (more than the vertical) drives the tide. In 1744 Jean le Rond d'Alembert studied tidal equations for
2295-526: A system of pulleys to add together six harmonic time functions. It was "programmed" by resetting gears and chains to adjust phasing and amplitudes. Similar machines were used until the 1960s. The first known sea-level record of an entire spring–neap cycle was made in 1831 on the Navy Dock in the Thames Estuary . Many large ports had automatic tide gauge stations by 1850. John Lubbock was one of
2448-576: A trade which provided the basis for strong economic growth in New Zealand. High demand for agricultural products from the United Kingdom and the United States helped New Zealanders achieve higher living standards than both Australia and Western Europe in the 1950s and 1960s. In 1973, New Zealand's export market was reduced when the United Kingdom joined the European Economic Community and other compounding factors, such as
2601-490: A yearly average of more than 2,000 hours of sunshine. The southern and southwestern parts of the South Island have a cooler and cloudier climate, with around 1,400–1,600 hours; the northern and northeastern parts of the South Island are the sunniest areas of the country and receive about 2,400–2,500 hours. The general snow season is early June until early October, though cold snaps can occur outside this season. Snowfall
2754-617: Is a constitutional monarchy with a parliamentary democracy , although its constitution is not codified . Charles III is the King of New Zealand and thus the head of state . The king is represented by the governor-general , whom he appoints on the advice of the prime minister . The governor-general can exercise the Crown 's prerogative powers , such as reviewing cases of injustice and making appointments of ministers , ambassadors, and other key public officials, and in rare situations,
2907-743: Is a member of the United Nations , the Commonwealth of Nations and the Organisation for Economic Co-operation and Development (OECD), and participates in the Five Power Defence Arrangements . Today, New Zealand enjoys particularly close relations with the United States and is one of its major non-NATO allies , as well as with Australia , with a " Trans-Tasman " identity between citizens of
3060-455: Is a useful concept. Tidal stage is also measured in degrees, with 360° per tidal cycle. Lines of constant tidal phase are called cotidal lines , which are analogous to contour lines of constant altitude on topographical maps , and when plotted form a cotidal map or cotidal chart . High water is reached simultaneously along the cotidal lines extending from the coast out into the ocean, and cotidal lines (and hence tidal phases) advance along
3213-480: Is also consistent with a much debated questionable third line of oral evidence, traditional genealogies ( whakapapa ) which point to around 1350 as a probable arrival date for many of the founding canoes ( waka ) from which many Māori trace their descent. Some Māori later migrated to the Chatham Islands where they developed their distinct Moriori culture. A later 1835 invasion by Māori resulted in
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#17327935438603366-626: Is an island country in the southwestern Pacific Ocean . It consists of two main landmasses—the North Island ( Te Ika-a-Māui ) and the South Island ( Te Waipounamu )—and over 700 smaller islands . It is the sixth-largest island country by area and lies east of Australia across the Tasman Sea and south of the islands of New Caledonia , Fiji , and Tonga . The country's varied topography and sharp mountain peaks, including
3519-422: Is at once cotidal with high and low waters, which is satisfied by zero tidal motion. (The rare exception occurs when the tide encircles an island, as it does around New Zealand, Iceland and Madagascar .) Tidal motion generally lessens moving away from continental coasts, so that crossing the cotidal lines are contours of constant amplitude (half the distance between high and low water) which decrease to zero at
3672-457: Is called the spring tide . It is not named after the season , but, like that word, derives from the meaning "jump, burst forth, rise", as in a natural spring . Spring tides are sometimes referred to as syzygy tides . When the Moon is at first quarter or third quarter, the Sun and Moon are separated by 90° when viewed from the Earth (in quadrature ), and the solar tidal force partially cancels
3825-582: Is classified as a non-self-governing territory , but is administered by a council of three elders (one from each Tokelauan atoll ). The Ross Dependency is New Zealand's territorial claim in Antarctica , where it operates the Scott Base research facility. New Zealand nationality law treats all parts of the realm equally, so most people born in New Zealand, the Cook Islands, Niue, Tokelau, and
3978-869: Is common in the eastern and southern parts of the South Island and mountain areas across the country. New Zealand's geographic isolation for 80 million years and island biogeography has influenced evolution of the country's species of animals , fungi and plants . Physical isolation has caused biological isolation, resulting in a dynamic evolutionary ecology with examples of distinctive plants and animals as well as populations of widespread species. The flora and fauna of New Zealand were originally thought to have originated from New Zealand's fragmentation off from Gondwana, however more recent evidence postulates species resulted from dispersal. About 82% of New Zealand's indigenous vascular plants are endemic , covering 1,944 species across 65 genera . The number of fungi recorded from New Zealand, including lichen-forming species,
4131-466: Is equivalent to 15% of the population of New Zealand. New Zealand has a strong presence among the Pacific Island countries, and enjoys strong diplomatic relations with Samoa , Fiji , and Tonga , and among smaller nations. A large proportion of New Zealand's aid goes to these countries, and many Pacific people migrate to New Zealand for employment. The increase of this since the 1960s led to
4284-459: Is exercised by the Government , led by the prime minister , currently Christopher Luxon . Charles III is the country's king and is represented by the governor-general , Cindy Kiro . In addition, New Zealand is organised into 11 regional councils and 67 territorial authorities for local government purposes. The Realm of New Zealand also includes Tokelau (a dependent territory );
4437-440: Is heavily dependent on international trade, particularly in agricultural products. Exports account for 24% of its output, making New Zealand vulnerable to international commodity prices and global economic slowdowns . Food products made up 55% of the value of all the country's exports in 2014; wood was the second largest earner (7%). New Zealand's main trading partners, as at June 2018 , are China ( NZ$ 27.8b), Australia ($ 26.2b),
4590-553: Is made up of two main islands and more than 700 smaller islands . The two main islands (the North Island , or Te Ika-a-Māui , and the South Island , or Te Waipounamu ) are separated by Cook Strait , 22 kilometres (14 mi) wide at its narrowest point. Besides the North and South Islands, the five largest inhabited islands are Stewart Island (across the Foveaux Strait ), Chatham Island , Great Barrier Island (in
4743-446: Is never time for the fluid to "catch up" to the state it would eventually reach if the tidal force were constant—the changing tidal force nonetheless causes rhythmic changes in sea surface height. When there are two high tides each day with different heights (and two low tides also of different heights), the pattern is called a mixed semi-diurnal tide . The changing distance separating the Moon and Earth also affects tide heights. When
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4896-436: Is not known, nor is the proportion of those fungi which are endemic, but one estimate suggests there are about 2,300 species of lichen-forming fungi in New Zealand and 40% of these are endemic. The two main types of forest are those dominated by broadleaf trees with emergent podocarps , or by southern beech in cooler climates. The remaining vegetation types consist of grasslands, the majority of which are tussock . Before
5049-408: Is not necessarily when the Moon is nearest to zenith or nadir , but the period of the forcing still determines the time between high tides. Because the gravitational field created by the Moon weakens with distance from the Moon, it exerts a slightly stronger than average force on the side of the Earth facing the Moon, and a slightly weaker force on the opposite side. The Moon thus tends to "stretch"
5202-461: Is not the case due to the free fall of the whole Earth, not only the oceans, towards these bodies) a different pattern of tidal forces would be observed, e.g. with a much stronger influence from the Sun than from the Moon: The solar gravitational force on the Earth is on average 179 times stronger than the lunar, but because the Sun is on average 389 times farther from the Earth, its field gradient
5355-402: Is shorter than average, and stronger tidal currents than average. Neaps result in less extreme tidal conditions. There is about a seven-day interval between springs and neaps. Tidal constituents are the net result of multiple influences impacting tidal changes over certain periods of time. Primary constituents include the Earth's rotation, the position of the Moon and Sun relative to the Earth,
5508-458: Is that, whether or not some settlers arrived before 1314, the main settlement period was in the subsequent decades, possibly involving a coordinated mass migration. It is also the broad consensus of historians that the Polynesian settlement of New Zealand was planned and deliberate. Over the centuries that followed, the settlers developed a distinct culture now known as Māori. This scenario
5661-419: Is the time required for the Earth to rotate once relative to the Moon. Simple tide clocks track this constituent. The lunar day is longer than the Earth day because the Moon orbits in the same direction the Earth spins. This is analogous to the minute hand on a watch crossing the hour hand at 12:00 and then again at about 1: 05 + 1 ⁄ 2 (not at 1:00). The Moon orbits the Earth in the same direction as
5814-519: Is to regulate "the natural environment with particular emphasis on resource management ", while territorial authorities are responsible for sewage, water, local roads, building consents, and other local matters. Five of the territorial councils are unitary authorities and also act as regional councils. The territorial authorities consist of 13 city councils, 53 district councils, and the Chatham Islands Council. While officially
5967-635: The 1973 oil and 1979 energy crises, led to a severe economic depression . Living standards in New Zealand fell behind those of Australia and Western Europe, and by 1982 New Zealand had the lowest per-capita income of all the developed nations surveyed by the World Bank . In the mid-1980s New Zealand deregulated its agricultural sector by phasing out subsidies over a three-year period. Since 1984, successive governments engaged in major macroeconomic restructuring (known first as Rogernomics and then Ruthanasia ), rapidly transforming New Zealand from
6120-872: The ANZAC tradition it shares with Australia. In addition to Vietnam and the two world wars, New Zealand fought in the Second Boer War , the Korean War , the Malayan Emergency , the Gulf War , and the Afghanistan War . It has contributed forces to several regional and global peacekeeping missions, such as those in Cyprus , Somalia , Bosnia and Herzegovina , the Sinai , Angola , Cambodia ,
6273-624: The Cook Islands and Niue (self-governing states in free association with New Zealand); and the Ross Dependency , which is New Zealand's territorial claim in Antarctica . The first European visitor to New Zealand, Dutch explorer Abel Tasman , named the islands Staten Land , believing they were part of the Staten Landt that Jacob Le Maire had sighted off the southern end of South America. Hendrik Brouwer proved that
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6426-606: The Coriolis effect , is generally clockwise in the southern hemisphere and counterclockwise in the northern hemisphere. The difference of cotidal phase from the phase of a reference tide is the epoch . The reference tide is the hypothetical constituent "equilibrium tide" on a landless Earth measured at 0° longitude, the Greenwich meridian. In the North Atlantic, because the cotidal lines circulate counterclockwise around
6579-722: The Euripus Strait and the Strait of Messina puzzled Aristotle .) Philostratus discussed tides in Book Five of The Life of Apollonius of Tyana . Philostratus mentions the moon, but attributes tides to "spirits". In Europe around 730 AD, the Venerable Bede described how the rising tide on one coast of the British Isles coincided with the fall on the other and described the time progression of high water along
6732-685: The European Union ($ 22.9b), the United States ($ 17.6b), and Japan ($ 8.4b). On 7 April 2008, New Zealand and China signed the New Zealand–China Free Trade Agreement , the first such agreement China has signed with a developed country. In July 2023, New Zealand and the European Union entered into the EU–New Zealand Free Trade Agreement , which eliminated tariffs on several goods traded between
6885-725: The Gondwanan supercontinent. About 25 million years ago, a shift in plate tectonic movements began to contort and crumple the region. This is now most evident in the Southern Alps, formed by compression of the crust beside the Alpine Fault . Elsewhere, the plate boundary involves the subduction of one plate under the other, producing the Puysegur Trench to the south, the Hikurangi Trough east of
7038-621: The Great Depression . The depression led to the election of the first Labour Government and the establishment of a comprehensive welfare state and a protectionist economy. New Zealand experienced increasing prosperity following the Second World War, and Māori began to leave their traditional rural life and move to the cities in search of work. A Māori protest movement developed, which criticised Eurocentrism and worked for greater recognition of Māori culture and of
7191-628: The Hauraki Gulf ), D'Urville Island (in the Marlborough Sounds ) and Waiheke Island (about 22 km (14 mi) from central Auckland). New Zealand is long and narrow—over 1,600 kilometres (990 mi) along its north-north-east axis with a maximum width of 400 kilometres (250 mi) —with about 15,000 km (9,300 mi) of coastline and a total land area of 268,000 square kilometres (103,500 sq mi). Because of its far-flung outlying islands and long coastline,
7344-522: The Iran–Iraq border, Bougainville , East Timor , and the Solomon Islands . New Zealand has an advanced market economy , ranked 13th in the 2021 Human Development Index , and fourth in the 2022 Index of Economic Freedom . It is a high-income economy with a nominal gross domestic product (GDP) per capita of US$ 36,254. The currency is the New Zealand dollar , informally known as
7497-584: The Legislative Council , until this was abolished in 1950. The supremacy of parliament over the Crown and other government institutions was established in England by the Bill of Rights 1689 and has been ratified as law in New Zealand. The House of Representatives is democratically elected, and a government is formed from the party or coalition with the majority of seats. If no majority is formed,
7650-530: The North Sea . Much later, in the late 20th century, geologists noticed tidal rhythmites , which document the occurrence of ancient tides in the geological record, notably in the Carboniferous . The tidal force produced by a massive object (Moon, hereafter) on a small particle located on or in an extensive body (Earth, hereafter) is the vector difference between the gravitational force exerted by
7803-611: The Pacific Community and the Pacific Islands Forum . It enjoys particularly close relations with the United States and is one of its major non-NATO allies ; the United Kingdom; Samoa , Fiji , and Tonga ; and with Australia , with a shared Trans-Tasman identity between the two countries stemming from centuries of British colonisation. Nationally, legislative authority is vested in an elected, unicameral Parliament , while executive political power
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#17327935438607956-546: The Southern Alps , owe much to tectonic uplift and volcanic eruptions. New Zealand's capital city is Wellington , and its most populous city is Auckland . The islands of New Zealand were the last large habitable land to be settled by humans. Between about 1280 and 1350, Polynesians began to settle in the islands and subsequently developed a distinctive Māori culture . In 1642, the Dutch explorer Abel Tasman became
8109-691: The Statute of Westminster , confirming that the British Parliament could no longer legislate for the country without its consent. The British government's residual legislative powers were later removed by the Constitution Act 1986 , and final rights of appeal to British courts were abolished in 2003. Early in the 20th century , New Zealand was involved in world affairs, fighting in the First and Second World Wars and suffering through
8262-723: The United Kingdom and negotiate a treaty with the Māori. The Treaty of Waitangi was first signed in the Bay of Islands on 6 February 1840. In response to the New Zealand Company's attempts to establish an independent settlement in Wellington , Hobson declared British sovereignty over all of New Zealand on 21 May 1840, even though copies of the treaty were still circulating throughout the country for Māori to sign. With
8415-624: The United States Department of State noted that the New Zealand government generally respected the rights of individuals, but voiced concerns regarding the social status of the Māori population. In terms of structural discrimination , the New Zealand Human Rights Commission has asserted that there is strong, consistent evidence that it is a real and ongoing socioeconomic issue. One example of structural inequality in New Zealand can be seen in
8568-401: The West Coast of the South Island to semi-arid in Central Otago and the Mackenzie Basin of inland Canterbury and subtropical in Northland . Of the seven largest cities, Christchurch is the driest, receiving on average only 618 millimetres (24.3 in) of rain per year and Wellington the wettest, receiving almost twice that amount. Auckland, Wellington and Christchurch all receive
8721-424: The caldera of one of the world's most active supervolcanoes . New Zealand is prone to earthquakes . The country owes its varied topography, and perhaps even its emergence above the waves, to the dynamic boundary it straddles between the Pacific and Indo-Australian Plates . New Zealand is part of Zealandia , a microcontinent nearly half the size of Australia that gradually submerged after breaking away from
8874-406: The endoskeleton through which podia for gas exchange project from the body. The mouth of the sand dollar is located on the bottom of its body at the center of the petal-like pattern. Unlike other urchins, the bodies of sand dollars also display secondary front-to-back bilateral symmetry with no morphological distinguishing features between males and females. The anus of sand dollars is located at
9027-440: The lunar theory of E W Brown describing the motions of the Moon, Arthur Thomas Doodson developed and published in 1921 the first modern development of the tide-generating potential in harmonic form: Doodson distinguished 388 tidal frequencies. Some of his methods remain in use. From ancient times, tidal observation and discussion has increased in sophistication, first marking the daily recurrence, then tides' relationship to
9180-578: The lunitidal interval . To make accurate records, tide gauges at fixed stations measure water level over time. Gauges ignore variations caused by waves with periods shorter than minutes. These data are compared to the reference (or datum) level usually called mean sea level . While tides are usually the largest source of short-term sea-level fluctuations, sea levels are also subject to change from thermal expansion , wind, and barometric pressure changes, resulting in storm surges , especially in shallow seas and near coasts. Tidal phenomena are not limited to
9333-430: The reserve powers (e.g. the power to dissolve Parliament or refuse the royal assent of a bill into law). The powers of the monarch and the governor-general are limited by constitutional constraints, and they cannot normally be exercised without the advice of ministers. The New Zealand Parliament holds legislative power and consists of the king and the House of Representatives . It also included an upper house,
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#17327935438609486-444: The seven-continent model. New Zealand's climate is predominantly temperate maritime ( Köppen : Cfb), with mean annual temperatures ranging from 10 °C (50 °F) in the south to 16 °C (61 °F) in the north. Historical maxima and minima are 42.4 °C (108.32 °F) in Rangiora , Canterbury and −25.6 °C (−14.08 °F) in Ranfurly , Otago . Conditions vary sharply across regions from extremely wet on
9639-446: The "Kiwi dollar"; it also circulates in the Cook Islands (see Cook Islands dollar ), Niue, Tokelau, and the Pitcairn Islands . Historically, extractive industries have contributed strongly to New Zealand's economy, focusing at different times on sealing, whaling, flax , gold, kauri gum , and native timber. The first shipment of refrigerated meat on the Dunedin in 1882 led to the establishment of meat and dairy exports to Britain,
9792-437: The 1980s, which transformed it from a protectionist to a liberalised free-trade economy. The service sector dominates the national economy , followed by the industrial sector, and agriculture ; international tourism is also a significant source of revenue. New Zealand is a member of the United Nations , Commonwealth of Nations , ANZUS , UKUSA , Five Eyes , OECD , ASEAN Plus Six , Asia-Pacific Economic Cooperation ,
9945-629: The 2024 Global Peace Index , New Zealand is the 4th most peaceful country in the world. New Zealand's military services—the New Zealand Defence Force —comprise the New Zealand Army , the Royal New Zealand Air Force , and the Royal New Zealand Navy . New Zealand's national defence needs are modest since a direct attack is unlikely. However, its military has had a global presence . The country fought in both world wars, with notable campaigns in Gallipoli , Crete , El Alamein , and Cassino . The Gallipoli campaign played an important part in fostering New Zealand's national identity and strengthened
10098-597: The Chatham Islands Council is not a unitary authority, it undertakes many functions of a regional council. The Realm of New Zealand, one of 15 Commonwealth realms , is the entire area over which the king or queen of New Zealand is sovereign and comprises New Zealand, Tokelau , the Ross Dependency , the Cook Islands , and Niue . The Cook Islands and Niue are self-governing states in free association with New Zealand. The New Zealand Parliament cannot pass legislation for these countries, but with their consent can act on behalf of them in foreign affairs and defence. Tokelau
10251-426: The Earth rotates on its axis, so it takes slightly more than a day—about 24 hours and 50 minutes—for the Moon to return to the same location in the sky. During this time, it has passed overhead ( culmination ) once and underfoot once (at an hour angle of 00:00 and 12:00 respectively), so in many places the period of strongest tidal forcing is the above-mentioned, about 12 hours and 25 minutes. The moment of highest tide
10404-419: The Earth slightly along the line connecting the two bodies. The solid Earth deforms a bit, but ocean water, being fluid, is free to move much more in response to the tidal force, particularly horizontally (see equilibrium tide ). As the Earth rotates, the magnitude and direction of the tidal force at any particular point on the Earth's surface change constantly; although the ocean never reaches equilibrium—there
10557-413: The Earth's accumulated dynamic tidal response to the applied forces, which response is influenced by ocean depth, the Earth's rotation, and other factors. In 1740, the Académie Royale des Sciences in Paris offered a prize for the best theoretical essay on tides. Daniel Bernoulli , Leonhard Euler , Colin Maclaurin and Antoine Cavalleri shared the prize. Maclaurin used Newton's theory to show that
10710-424: The Government as a major societal issue; the country has 12.0% of children living in low-income households that had less than 50% of the median equivalised disposable household income as of June 2022 . Poverty has a disproportionately high effect in ethnic-minority households, with a quarter (23.3%) of Māori children and almost a third (28.6%) of Pacific Islander children living in poverty as of 2020 . New Zealand
10863-410: The MMP system, each person has two votes; one is for a candidate standing in the voter's electorate , and the other is for a party. Based on the 2018 census data, there are 72 electorates (which include seven Māori electorates in which only Māori can optionally vote), and the remaining 48 of the 120 seats are assigned so that representation in Parliament reflects the party vote, with the threshold that
11016-427: The Moon and its phases. Bede starts by noting that the tides rise and fall 4/5 of an hour later each day, just as the Moon rises and sets 4/5 of an hour later. He goes on to emphasise that in two lunar months (59 days) the Moon circles the Earth 57 times and there are 114 tides. Bede then observes that the height of tides varies over the month. Increasing tides are called malinae and decreasing tides ledones and that
11169-459: The Moon is closest, at perigee , the range increases, and when it is at apogee , the range shrinks. Six or eight times a year perigee coincides with either a new or full moon causing perigean spring tides with the largest tidal range . The difference between the height of a tide at perigean spring tide and the spring tide when the moon is at apogee depends on location but can be large as a foot higher. These include solar gravitational effects,
11322-462: The Moon on the particle, and the gravitational force that would be exerted on the particle if it were located at the Earth's center of mass. Whereas the gravitational force subjected by a celestial body on Earth varies inversely as the square of its distance to the Earth, the maximal tidal force varies inversely as, approximately, the cube of this distance. If the tidal force caused by each body were instead equal to its full gravitational force (which
11475-457: The Moon's altitude (elevation) above the Earth's Equator, and bathymetry . Variations with periods of less than half a day are called harmonic constituents . Conversely, cycles of days, months, or years are referred to as long period constituents. Tidal forces affect the entire earth , but the movement of solid Earth occurs by mere centimeters. In contrast, the atmosphere is much more fluid and compressible so its surface moves by kilometers, in
11628-449: The Moon's tidal force. At these points in the lunar cycle, the tide's range is at its minimum; this is called the neap tide , or neaps . "Neap" is an Anglo-Saxon word meaning "without the power", as in forðganges nip (forth-going without-the-power). Neap tides are sometimes referred to as quadrature tides . Spring tides result in high waters that are higher than average, low waters that are lower than average, " slack water " time that
11781-449: The Moon. Abu Ma'shar discussed the effects of wind and Moon's phases relative to the Sun on the tides. In the 12th century, al-Bitruji (d. circa 1204) contributed the notion that the tides were caused by the general circulation of the heavens. Simon Stevin , in his 1608 De spiegheling der Ebbenvloet ( The theory of ebb and flood ), dismissed a large number of misconceptions that still existed about ebb and flood. Stevin pleaded for
11934-553: The Māori of later years. According to an early European synthesized interpretation of various Māori traditional accounts, around 750 CE the heroic explorer, Kupe , had discovered New Zealand and later, around 1350, one great fleet of settlers set out from Hawaiki in eastern Polynesia. However, from the late 20th century, this story has been increasingly relegated to the realm of legend and myth. An alternative view has emerged from fresh archaeological and scientific evidence, which correlates with doubts raised by historians everywhere as to
12087-771: The North Island and South Island had never been formalised, and names and alternative names were formalised in 2013. This set the names as North Island or Te Ika-a-Māui , and South Island or Te Waipounamu . For each island, either its English or Māori name can be used, or both can be used together. Similarly the Māori and English names for the whole country are sometimes used together ( Aotearoa New Zealand ); however, this has no official recognition. The first people to reach New Zealand were Polynesians in ocean going waka (canoes). Their arrival likely occurred in several waves, approximately between 1280 and 1350 CE. Those Polynesian settlers, isolated in New Zealand, became
12240-602: The North Island, and the Kermadec and Tonga Trenches further north. New Zealand, together with Australia, is part of a wider region known as Australasia . It also forms the southwestern extremity of the geographic and ethnographic region called Polynesia . Oceania is a wider region encompassing the Australian continent , New Zealand, and various island countries in the Pacific Ocean that are not included in
12393-614: The North Island, saw thousands of imperial troops and the Royal Navy come to New Zealand and became known as the New Zealand Wars . Following these armed conflicts, large areas of Māori land were confiscated by the government to meet settler demands. The colony gained a representative government in 1852 , and the first Parliament met in 1854. In 1856 the colony effectively became self-governing, gaining responsibility over all domestic matters (except native policy, which
12546-684: The Northumbrian coast. The first tide table in China was recorded in 1056 AD primarily for visitors wishing to see the famous tidal bore in the Qiantang River . The first known British tide table is thought to be that of John Wallingford, who died Abbot of St. Albans in 1213, based on high water occurring 48 minutes later each day, and three hours earlier at the Thames mouth than upriver at London . In 1614 Claude d'Abbeville published
12699-630: The Ross Dependency are New Zealand citizens. During the period of the New Zealand colony, Britain was responsible for external trade and foreign relations. The 1923 and 1926 Imperial Conferences decided that New Zealand should be allowed to negotiate its own political treaties , and the first commercial treaty was ratified in 1928 with Japan. On 3 September 1939, New Zealand allied itself with Britain and declared war on Germany with Prime Minister Michael Joseph Savage proclaiming, "Where she goes, we go; where she stands, we stand". In 1951,
12852-674: The South American land was a small island in 1643, and Dutch cartographers subsequently renamed Tasman's discovery Nova Zeelandia from Latin , after the Dutch province of Zeeland . This name was later anglicised to New Zealand . This was written as Nu Tireni in the Māori language (spelled Nu Tirani in Te Tiriti o Waitangi). In 1834 a document written in Māori and entitled " He Wakaputanga o te Rangatiratanga o Nu Tireni "
13005-531: The Sun and moon. Pytheas travelled to the British Isles about 325 BC and seems to be the first to have related spring tides to the phase of the moon. In the 2nd century BC, the Hellenistic astronomer Seleucus of Seleucia correctly described the phenomenon of tides in order to support his heliocentric theory. He correctly theorized that tides were caused by the moon , although he believed that
13158-476: The Tarawera eruption except for three of a decade or so earlier. Radiocarbon dating and pollen evidence of widespread forest fires shortly before the eruption might also indicate a pre-eruption human presence. Additionally, mitochondrial DNA variability within the Māori populations suggest that Eastern Polynesians first settled the New Zealand archipelago between 1250 and 1300, Therefore, current opinion
13311-470: The Treaty of Waitangi. In 1975, a Waitangi Tribunal was set up to investigate alleged breaches of the Treaty, and it was enabled to investigate historic grievances in 1985. The government has negotiated settlements of these grievances with many iwi, although Māori claims to the foreshore and seabed proved controversial in the 2000s. New Zealand is located near the centre of the water hemisphere and
13464-531: The Two Chief World Systems , whose working title was Dialogue on the Tides , gave an explanation of the tides. The resulting theory, however, was incorrect as he attributed the tides to the sloshing of water caused by the Earth's movement around the Sun. He hoped to provide mechanical proof of the Earth's movement. The value of his tidal theory is disputed. Galileo rejected Kepler's explanation of
13617-659: The United Kingdom became increasingly focused on its European interests, while New Zealand joined Australia and the United States in the ANZUS security treaty. The influence of the United States on New Zealand weakened following protests over the Vietnam War , the refusal of the United States to admonish France after the sinking of the Rainbow Warrior , disagreements over environmental and agricultural trade issues, and New Zealand's nuclear-free policy . Despite
13770-524: The United States's suspension of ANZUS obligations, the treaty remained in effect between New Zealand and Australia, whose foreign policy has followed a similar historical trend. Close political contact is maintained between the two countries, with free trade agreements and travel arrangements that allow citizens to visit, live and work in both countries without restrictions. In 2013 there were about 650,000 New Zealand citizens living in Australia, which
13923-423: The amphidromic point, the high tide passes New York Harbor approximately an hour ahead of Norfolk Harbor. South of Cape Hatteras the tidal forces are more complex, and cannot be predicted reliably based on the North Atlantic cotidal lines. Investigation into tidal physics was important in the early development of celestial mechanics , with the existence of two daily tides being explained by the Moon's gravity. Later
14076-429: The amphidromic point. For a semi-diurnal tide the amphidromic point can be thought of roughly like the center of a clock face, with the hour hand pointing in the direction of the high water cotidal line, which is directly opposite the low water cotidal line. High water rotates about the amphidromic point once every 12 hours in the direction of rising cotidal lines, and away from ebbing cotidal lines. This rotation, caused by
14229-510: The appearance of the tests (skeletons) of dead individuals after being washed ashore. The test lacks its velvet-like skin of spines and has often been bleached white by sunlight . To beachcombers of the past, this suggested a large, silver coin, such as the old Spanish dollar , which had a diameter of 38–40 mm. Other names for the sand dollar include sand cakes, pansy shells, snapper biscuits, cake urchins, and sea cookies. In South Africa, they are known as pansy shells from their suggestion of
14382-438: The arrival of humans, an estimated 80% of the land was covered in forest, with only high alpine , wet, infertile and volcanic areas without trees. Massive deforestation occurred after humans arrived, with around half the forest cover lost to fire after Polynesian settlement. Much of the remaining forest fell after European settlement, being logged or cleared to make room for pastoral farming, leaving forest occupying only 23% of
14535-547: The atmosphere which did not include rotation. In 1770 James Cook 's barque HMS Endeavour grounded on the Great Barrier Reef . Attempts were made to refloat her on the following tide which failed, but the tide after that lifted her clear with ease. Whilst she was being repaired in the mouth of the Endeavour River Cook observed the tides over a period of seven weeks. At neap tides both tides in
14688-509: The back rather than at the top as in most urchins, with many more bilateral features appearing in some species. These result from the adaptation of sand dollars, in the course of their evolution , from creatures that originally lived their lives on top of the seabed ( epibenthos ) to creatures that burrow beneath it ( endobenthos ). According to World Register of Marine Species : Sand dollars can be found in temperate and tropical zones along all continents. Sand dollars live in waters below
14841-404: The canoe of Aoraki ' ) for the South Island . Early European maps labelled the islands North (North Island), Middle (South Island), and South ( Stewart Island / Rakiura ). In 1830, mapmakers began to use "North" and "South" on their maps to distinguish the two largest islands, and by 1907, this was the accepted norm. The New Zealand Geographic Board discovered in 2009 that the names of
14994-410: The coast. Semi-diurnal and long phase constituents are measured from high water, diurnal from maximum flood tide. This and the discussion that follows is precisely true only for a single tidal constituent. For an ocean in the shape of a circular basin enclosed by a coastline, the cotidal lines point radially inward and must eventually meet at a common point, the amphidromic point . The amphidromic point
15147-474: The consequences of these decisions. The 42nd and current prime minister, since 27 November 2023, is Christopher Luxon . A parliamentary general election must be called no later than three years after the previous election. Almost all general elections between 1853 and 1993 were held under the first-past-the-post voting system. Since the 1996 election , a form of proportional representation called mixed-member proportional (MMP) has been used. Under
15300-461: The country has extensive marine resources. Its exclusive economic zone is one of the largest in the world, covering more than 15 times its land area. The South Island is the largest landmass of New Zealand. It is divided along its length by the Southern Alps . There are 18 peaks over 3,000 metres (9,800 ft), the highest of which is Aoraki / Mount Cook at 3,724 metres (12,218 ft). Fiordland 's steep mountains and deep fiords record
15453-502: The criminal justice system. According to the Ministry of Justice , Māori are overrepresented, comprising 45% of New Zealanders convicted of crimes and 53% of those imprisoned, while only being 16.5% of the population. The early European settlers divided New Zealand into provinces , which had a degree of autonomy. Because of financial pressures and the desire to consolidate railways, education, land sales, and other policies, government
15606-480: The daily tides were explained more precisely by the interaction of the Moon's and the Sun's gravity. Seleucus of Seleucia theorized around 150 BC that tides were caused by the Moon. The influence of the Moon on bodies of water was also mentioned in Ptolemy 's Tetrabiblos . In De temporum ratione ( The Reckoning of Time ) of 725 Bede linked semidurnal tides and the phenomenon of varying tidal heights to
15759-690: The early 19th century, Christian missionaries began to settle New Zealand, eventually converting most of the Māori population. The Māori population declined to around 40% of its pre-contact level during the 19th century; introduced diseases were the major factor. The British Government appointed James Busby as British Resident to New Zealand in 1832. His duties, given to him by Governor Bourke in Sydney, were to protect settlers and traders "of good standing", prevent "outrages" against Māori, and apprehend escaped convicts. In 1835, following an announcement of impending French settlement by Charles de Thierry ,
15912-405: The extensive ice age glaciation of this southwestern corner of the South Island. The North Island is less mountainous but is marked by volcanism . The highly active Taupō Volcanic Zone has formed a large volcanic plateau , punctuated by the North Island's highest mountain, Mount Ruapehu (2,797 metres (9,177 ft)). The plateau also hosts the country's largest lake, Lake Taupō , nestled in
16065-649: The first European to sight and record New Zealand. In 1769 the British explorer Captain James Cook became the first European to set foot on and map New Zealand. In 1840, representatives of the United Kingdom and Māori chiefs signed the Treaty of Waitangi which paved the way for Britain's declaration of sovereignty later that year and the establishment of the Crown Colony of New Zealand in 1841. Subsequently,
16218-538: The first to map co-tidal lines, for Great Britain, Ireland and adjacent coasts, in 1840. William Whewell expanded this work ending with a nearly global chart in 1836. In order to make these maps consistent, he hypothesized the existence of a region with no tidal rise or fall where co-tidal lines meet in the mid-ocean. The existence of such an amphidromic point , as they are now known, was confirmed in 1840 by Captain William Hewett, RN , from careful soundings in
16371-491: The formation of the Pasifika New Zealander pan-ethnic group, the fourth-largest ethnic grouping in the country. Permanent migration is regulated under the 1970 Samoan Quota Scheme and the 2002 Pacific Access Category, which allow up to 1,100 Samoan nationals and up to 750 other Pacific Islanders respectively to become permanent New Zealand residents each year. A seasonal workers scheme for temporary migration
16524-420: The highest level to the lowest: The semi-diurnal range (the difference in height between high and low waters over about half a day) varies in a two-week cycle. Approximately twice a month, around new moon and full moon when the Sun, Moon, and Earth form a line (a configuration known as a syzygy ), the tidal force due to the Sun reinforces that due to the Moon. The tide's range is then at its maximum; this
16677-415: The idea that the attraction of the Moon was responsible for the tides and spoke in clear terms about ebb, flood, spring tide and neap tide , stressing that further research needed to be made. In 1609 Johannes Kepler also correctly suggested that the gravitation of the Moon caused the tides, which he based upon ancient observations and correlations. Galileo Galilei in his 1632 Dialogue Concerning
16830-468: The interaction was mediated by the pneuma . He noted that tides varied in time and strength in different parts of the world. According to Strabo (1.1.9), Seleucus was the first to link tides to the lunar attraction, and that the height of the tides depends on the moon's position relative to the Sun. The Naturalis Historia of Pliny the Elder collates many tidal observations, e.g., the spring tides are
16983-580: The islands are uninhabited except for about six people at Raoul Island station. These islands put the northern border of New Zealand at 29 degrees South latitude. After the 1982 UNCLOS , the islands contributed significantly to New Zealand's exclusive economic zone . In 1891, the Liberal Party came to power as the first organised political party. The Liberal Government , led by Richard Seddon for most of its period in office, passed many important social and economic measures. In 1893, New Zealand
17136-436: The judiciary to interpret the law based solely on the legislation enacted by Parliament without other influences on their decisions. New Zealand is identified as one of the world's most stable and well-governed states. As of 2017, the country was ranked fourth in the strength of its democratic institutions, and first in government transparency and lack of corruption . LGBT rights in the nation are also recognised as among
17289-511: The land in 1997. The forests were dominated by birds , and the lack of mammalian predators led to some like the kiwi , kākāpō , weka and takahē evolving flightlessness . The arrival of humans, associated changes to habitat, and the introduction of rats , ferrets and other mammals led to the extinction of many bird species, including large birds like the moa and Haast's eagle . Other indigenous animals are represented by reptiles ( tuatara , skinks and geckos ), frogs , such as
17442-403: The largest minority, followed by Asians and Pasifika . Reflecting this, New Zealand's culture is mainly derived from Māori and early British settlers, with recent broadening of culture arising from increased immigration to the country . The official languages are English, Māori , and New Zealand Sign Language , with the local dialect of English being dominant. A developed country , it
17595-641: The latter being common. New Zealand is a member of the Five Eyes intelligence sharing agreement, known formally as the UKUSA Agreement . The five members of this agreement compromise the core Anglosphere : Australia, Canada, New Zealand, the United Kingdom, and the United States. Since 2012, New Zealand has had a partnership arrangement with NATO under the Partnership Interoperability Initiative. According to
17748-456: The long white cloud') is the current Māori name for New Zealand. It is unknown whether Māori had a name for the whole country before the arrival of Europeans; Aotearoa originally referred to just the North Island . Māori had several traditional names for the two main islands, including Te Ika-a-Māui ( ' the fish of Māui ' ) for the North Island and Te Waipounamu ( ' the waters of greenstone ' ) or Te Waka o Aoraki ( '
17901-589: The longest recession in over thirty years, and unemployment rising back to 7% in late 2009. The lowest unemployment rate recorded using the current methodology was in December 2021 during the COVID-19 pandemic , at 3.2%. Unemployment rates for different age groups follow similar trends but are consistently higher among youth. During the September 2021 quarter, the general unemployment rate was around 3.2%, while
18054-455: The massacre and virtual extinction of the Moriori. In a hostile 1642 encounter between Ngāti Tūmatakōkiri and Dutch explorer Abel Tasman 's crew, four of Tasman's crew members were killed, and at least one Māori was hit by canister shot . Europeans did not revisit New Zealand until 1769, when British explorer James Cook mapped almost the entire coastline. Following Cook, New Zealand
18207-534: The mean low tide line, on or just beneath the surface of sandy and muddy areas. The common sand dollar, Echinarachnius parma , can be found in the Northern Hemisphere from the intertidal zone to the depths of the ocean, while the keyhole sand dollars (three species of the genus Mellita ) can be found on many a wide range of coasts in and around the Caribbean Sea . The spines on
18360-412: The month is divided into four parts of seven or eight days with alternating malinae and ledones . In the same passage he also notes the effect of winds to hold back tides. Bede also records that the time of tides varies from place to place. To the north of Bede's location ( Monkwearmouth ) the tides are earlier, to the south later. He explains that the tide "deserts these shores in order to be able all
18513-514: The more to be able to flood other [shores] when it arrives there" noting that "the Moon which signals the rise of tide here, signals its retreat in other regions far from this quarter of the heavens". Later medieval understanding of the tides was primarily based on works of Muslim astronomers , which became available through Latin translation starting from the 12th century. Abu Ma'shar al-Balkhi (d. circa 886), in his Introductorium in astronomiam , taught that ebb and flood tides were caused by
18666-485: The most tolerant in Oceania . New Zealand ranks highly for civic participation in the political process, with 82% voter turnout during recent general elections, compared to an OECD average of 69%. However, this is untrue for local council elections; a historically low 36% of eligible New Zealanders voted in the 2022 local elections , compared with an already low 42% turnout in 2019 . A 2017 human rights report by
18819-719: The nebulous United Tribes of New Zealand sent a Declaration of Independence to King William IV of the United Kingdom asking for protection. Ongoing unrest, the proposed settlement of New Zealand by the New Zealand Company (which had already sent its first ship of surveyors to buy land from Māori) and the dubious legal standing of the Declaration of Independence prompted the Colonial Office to send Captain William Hobson to claim sovereignty for
18972-475: The number of dairy cows doubling between 1990 and 2007, to become New Zealand's largest export earner. In the year to June 2018, dairy products accounted for 17.7% ($ 14.1 billion) of total exports, and the country's largest company, Fonterra , controls almost one-third of the international dairy trade. Other exports in 2017–18 were meat (8.8%), wood and wood products (6.2%), fruit (3.6%), machinery (2.2%) and wine (2.1%). New Zealand's wine industry has followed
19125-420: The obliquity (tilt) of the Earth's Equator and rotational axis, the inclination of the plane of the lunar orbit and the elliptical shape of the Earth's orbit of the Sun. A compound tide (or overtide) results from the shallow-water interaction of its two parent waves. Because the M 2 tidal constituent dominates in most locations, the stage or phase of a tide, denoted by the time in hours after high water,
19278-426: The oceans, but can occur in other systems whenever a gravitational field that varies in time and space is present. For example, the shape of the solid part of the Earth is affected slightly by Earth tide , though this is not as easily seen as the water tidal movements. Four stages in the tidal cycle are named: Oscillating currents produced by tides are known as tidal streams or tidal currents . The moment that
19431-529: The other irregular echinoids, namely the cassiduloids , during the early Jurassic , with the first true sand dollar genus, Togocyamus , arising during the Paleocene . Soon after Togocyamus , more modern-looking groups emerged during the Eocene . Sand dollars are small in size, averaging from 80 to 100 mm (3 to 4 inches). As with all members of the order Clypeasteroida, they possess a rigid skeleton called
19584-435: The predatory fish but may make them more vulnerable to attacks from smaller predators like crustaceans. Sand dollars will also clone themselves during normal asexual reproduction. Larvae will undergo this process when food is plentiful or temperature conditions are optimal. Cloning may also occur to make use of the tissues that are normally lost during metamorphosis. The flattened test of the sand dollar allows it to burrow into
19737-411: The predicted times and amplitude (or " tidal range "). The predictions are influenced by many factors including the alignment of the Sun and Moon, the phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see Timing ). They are however only predictions, the actual time and height of
19890-408: The problem from the perspective of a static system (equilibrium theory), that provided an approximation that described the tides that would occur in a non-inertial ocean evenly covering the whole Earth. The tide-generating force (or its corresponding potential ) is still relevant to tidal theory, but as an intermediate quantity (forcing function) rather than as a final result; theory must also consider
20043-442: The protected endangered Hamilton's Frog , spiders , insects ( wētā ), and snails. Some, such as the tuatara, are so unique that they have been called living fossils . Three species of bats ( one since extinct) were the only sign of native land mammals in New Zealand until the 2006 discovery of bones from a unique, mouse-sized land mammal at least 16 million years old. Marine mammals, however, are abundant, with almost half
20196-575: The reliability of interpretations drawn from the oral evidence of indigenous peoples, including from Māori. Regarding the arrival of these Polynesian settlers, there are no human remains, artefacts or structures which are confidently dated to earlier than the Kaharoa Tephra, a layer of volcanic debris deposited by the Mount Tarawera eruption around 1314 CE. Samples of rat bone, rat-gnawed shells and seed cases have given dates later than
20349-451: The sand and remain hidden from sight from potential predators. Predators of the sand dollar are the fish species cod, flounder, sheepshead and haddock. These fish will prey on sand dollars even through their tough exterior. Sand dollars have spines on their bodies that help them to move around the ocean floor. When a sand dollar dies, it loses the spines and becomes smooth as the exoskeleton is then exposed. New Zealand New Zealand
20502-448: The sense of the contour level of a particular low pressure in the outer atmosphere. In most locations, the largest constituent is the principal lunar semi-diurnal , also known as the M2 tidal constituent or M 2 tidal constituent . Its period is about 12 hours and 25.2 minutes, exactly half a tidal lunar day , which is the average time separating one lunar zenith from the next, and thus
20655-594: The signing of the treaty and declaration of sovereignty, the number of immigrants, particularly from the United Kingdom, began to increase. New Zealand was administered as a dependency of the Colony of New South Wales until becoming a separate Crown colony , the Colony of New Zealand , on 3 May 1841. Armed conflict began between the colonial government and Māori in 1843 with the Wairau Affray over land and disagreements over sovereignty. These conflicts, mainly in
20808-593: The somewhat flattened topside and underside of the animal allow it to burrow or creep through the sediment when looking for shelter or food. Fine, hair-like cilia cover these tiny spines. Sand dollars usually eat algae and organic matter found along the ocean floor, though some species will tip on their side to catch organic matter floating in ocean currents. Sand dollars frequently gather on the ocean floor, in part to their preference for soft bottom areas, which are convenient for their reproduction . The sexes are separate and, as with most echinoids, gametes are released into
20961-652: The spines enable sand dollars to move across the seabed. The velvety spines of live sand dollars appear in a variety of colors—green, blue, violet, or purple—depending on the species. Individuals which are very recently dead or dying (moribund) are sometimes found on beaches with much of the external morphology still intact. Dead individuals are commonly found with their empty test devoid of all surface material and bleached white by sunlight. The bodies of adult sand dollars, like those of other echinoids , display radial symmetry . The petal-like pattern in sand dollars consists of five paired rows of pores. The pores are perforations in
21114-443: The tidal current ceases is called slack water or slack tide . The tide then reverses direction and is said to be turning. Slack water usually occurs near high water and low water, but there are locations where the moments of slack tide differ significantly from those of high and low water. Tides are commonly semi-diurnal (two high waters and two low waters each day), or diurnal (one tidal cycle per day). The two high waters on
21267-399: The tide is affected by wind and atmospheric pressure . Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal tide—one high and low tide each day. A "mixed tide"—two uneven magnitude tides a day—is a third regular category. Tides vary on timescales ranging from hours to years due to a number of factors, which determine
21420-494: The tides. Isaac Newton (1642–1727) was the first person to explain tides as the product of the gravitational attraction of astronomical masses. His explanation of the tides (and many other phenomena) was published in the Principia (1687) and used his theory of universal gravitation to explain the lunar and solar attractions as the origin of the tide-generating forces. Newton and others before Pierre-Simon Laplace worked
21573-467: The total workforce in 2016. In 2017, international visitor arrivals were expected to increase at a rate of 5.4% annually up to 2022. Wool was New Zealand's major agricultural export during the late 19th century. Even as late as the 1960s it made up over a third of all export revenues, but since then its price has steadily dropped relative to other commodities, and wool is no longer profitable for many farmers. In contrast, dairy farming increased, with
21726-486: The two regions. This free trade agreement expanded on the pre-existing free trade agreement and saw a reduction in tariffs on meat and dairy in response to feedback from the affected industries. The service sector is the largest sector in the economy, followed by manufacturing and construction and then farming and raw material extraction. Tourism plays a significant role in the economy, contributing $ 12.9 billion (or 5.6%) to New Zealand's total GDP and supporting 7.5% of
21879-481: The unemployment rate for youth aged 15 to 24 was 9.2%. New Zealand has experienced a series of " brain drains " since the 1970s that still continue today. Nearly one-quarter of highly skilled workers live overseas, mostly in Australia and Britain, which is the largest proportion from any developed nation. In recent decades, however, a " brain gain " has brought in educated professionals from Europe and less developed countries. Today New Zealand's economy benefits from
22032-403: The water column and go through external fertilization . The nektonic larvae metamorphose through several stages before the skeleton or test begins to form, at which point they become benthic . In 2008, biologists discovered that sand dollar larvae will clone themselves for a few different reasons. When a predator is near, certain species of sand dollar larvae will split themselves in half in
22185-480: The work " Histoire de la mission de pères capucins en l'Isle de Maragnan et terres circonvoisines ", where he exposed that the Tupinambá people already had an understanding of the relation between the Moon and the tides before Europe. William Thomson (Lord Kelvin) led the first systematic harmonic analysis of tidal records starting in 1867. The main result was the building of a tide-predicting machine using
22338-847: The world's cetaceans (whales, dolphins, and porpoises ) and large numbers of fur seals reported in New Zealand waters. Many seabirds breed in New Zealand, a third of them unique to the country. More penguin species are found in New Zealand than in any other country, with 13 of the world's 18 penguin species. Since human arrival, almost half of the country's vertebrate species have become extinct, including at least fifty-one birds, three frogs, three lizards, one freshwater fish, and one bat. Others are endangered or have had their range severely reduced. However, New Zealand conservationists have pioneered several methods to help threatened wildlife recover, including island sanctuaries, pest control, wildlife translocation, fostering, and ecological restoration of islands and other protected areas . New Zealand
22491-569: Was centralised and the provinces were abolished in 1876. The provinces are remembered in regional public holidays and sporting rivalries. Since 1876, various councils have administered local areas under legislation determined by the central government. In 1989, the government reorganised local government into the current two-tier structure of regional councils and territorial authorities . The 249 municipalities that existed in 1975 have now been consolidated into 67 territorial authorities and 11 regional councils. The regional councils' role
22644-472: Was granted in the mid-1860s). Following concerns that the South Island might form a separate colony, premier Alfred Domett moved a resolution to transfer the capital from Auckland to a locality near Cook Strait . Wellington was chosen for its central location, with Parliament officially sitting there for the first time in 1865. In 1886, New Zealand annexed the volcanic Kermadec Islands , about 1,000 km (620 mi) northeast of Auckland. Since 1937,
22797-615: Was introduced in 2007, and in 2009 about 8,000 Pacific Islanders were employed under it. New Zealand is involved in the Pacific Islands Forum , the Pacific Community , Asia-Pacific Economic Cooperation , and the Association of Southeast Asian Nations Regional Forum (including the East Asia Summit ). New Zealand has been described as a middle power in the Asia-Pacific region, and an emerging power . The country
22950-584: Was the first nation in the world to grant all women the right to vote and pioneered the adoption of compulsory arbitration between employers and unions in 1894. The Liberals also guaranteed a minimum wage in 1894, a world first. In 1907, at the request of the New Zealand Parliament, King Edward VII proclaimed New Zealand a Dominion within the British Empire , reflecting its self-governing status. In 1947, New Zealand adopted
23103-429: Was the first to introduce a minimum wage , and the first to give women the right to vote . It ranks very highly in international measures of quality of life , human rights , and it has one of the lowest levels of perceived corruption in the world. It retains visible levels of inequality , having structural disparities between its Māori and European populations. New Zealand underwent major economic changes during
23256-789: Was translated into English and became the Declaration of the Independence of New Zealand . It was prepared by Te W(h)akaminenga o Nga Rangatiratanga o Nga Hapu o Nu Tireni , the United Tribes of New Zealand , and a copy was sent to King William IV who had already acknowledged the flag of the United Tribes of New Zealand, and who recognised the declaration in a letter from Lord Glenelg . Aotearoa (pronounced [aɔˈtɛaɾɔa] in Māori and / ˌ aʊ t ɛəˈr oʊ . ə / in English; often translated as 'land of
23409-528: Was visited by numerous European and North American whaling , sealing , and trading ships. They traded European food, metal tools, weapons, and other goods for timber, Māori food, artefacts, and water. The introduction of the potato and the musket transformed Māori agriculture and warfare. Potatoes provided a reliable food surplus, which enabled longer and more sustained military campaigns. The resulting intertribal Musket Wars encompassed over 600 battles between 1801 and 1840, killing 30,000–40,000 Māori. From
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