Administrative divisions
The United Mexican States are a federated union of thirty-one free and sovereign states which form a Union that exercises jurisdiction over the Federal District and other territories. Each state has its own constitution and congress, as well as a judiciary, and its citizens elect by direct voting, a governor (gobernador) for a six-year term, as well as representatives (diputados locales) to their respective state congresses, for three-year terms. The 31 states and the Federal District are collectively called "federal entities", and all are equally represented in the Congress of the Union.
Mexican states are also divided into municipalities (municipios), the smallest official political entity in the country, governed by a mayor or "municipal president" (presidente municipal), elected by its residents by plurality. Municipalities can be further subdivided into non-autonomous boroughs or in semi-autonomous auxiliary presidencies.
Constitutionally, Mexico City, as the capital of the federation and seat of the powers of the Union, is the Federal District, a special political division in Mexico that belongs to the federation as a whole and not to a particular state, and as such, has more limited local rule than the nation's states. Nonetheless, since 1987 it has progressively gained a greater degree of autonomy, and residents now elect a head of government (Jefe de Gobierno) and representatives of a Legislative Assembly directly. Unlike the states, the Federal District does not have a constitution but a statute of government. Mexico City is conterminous and coextensive with the Federal District.
Geography and climate
A picture of Mexico seen from space.Situated in the Americas at about 23° N and 102° W,[43] Mexico comprises much of southern North America. Mexico is also described as within the region of Middle America. Physiographically, the lands east of the Isthmus of Tehuantepec including the Yucatán Peninsula (which together comprise around 12% of the country's area) lie within the region of Central America; alternatively, the Trans-Mexican Volcanic Belt geologically delimits the region on the north. Geopolitically, however, Mexico is commonly considered a North American country.
Mexico's total area is 1,972,550 km², including approximately 6,000 km² of islands in the Pacific Ocean (including the remote Guadalupe Island and the Islas Revillagigedo), Gulf of Mexico, Caribbean Sea, and Gulf of California. On its north, Mexico shares a 3,141 km border with the United States. The meandering Río Bravo del Norte (known as the Rio Grande in the United States) defines the border from Ciudad Juárez east to the Gulf of Mexico. A series of natural and artificial markers delineate the United States-Mexican border west from Ciudad Juárez to the Pacific Ocean. On its south, Mexico shares an 871 km border with Guatemala and a 251 km border with Belize.
Topography
Topographic map of MexicoThe Mexican territory is crossed from north to south by two mountain ranges known as Sierra Madre Oriental and Sierra Madre Occidental, which are the extension of the Rocky Mountains from northern North America. From east to west at the center, the country is crossed by the Trans-Mexican Volcanic Belt also known as the Sierra Nevada. A fourth mountain range, the Sierra Madre del Sur, runs from Michoacán to Oaxaca. As such, the majority of the Mexican central and northern territories are located at high altitudes, and the highest elevations are found at the Trans-Mexican Volcanic Belt: Pico de Orizaba (5,700 m), Popocatépetl (5,462 m) and Iztaccíhuatl (5,286 m) and the Nevado de Toluca (4,577 m). Three major urban agglomerations are located in the valleys between these four elevations: Toluca, Greater Mexico City and Puebla.
Climate
Map of climates in MexicoThe Tropic of Cancer effectively divides the country into temperate and tropical zones. Land north of the twenty-fourth parallel experiences cooler temperatures during the winter months. South of the twenty-fourth parallel, temperatures are fairly constant year round and vary solely as a function of elevation.
Areas south of the twenty-fourth parallel with elevations up to 1,000 meters (the southern parts of both coastal plains as well as the Yucatán Peninsula), have a yearly median temperature between 24 and 28 °C. Temperatures here remain high throughout the year, with only a 5 °C difference between winter and summer median temperatures. Although low-lying areas north of the twentieth-fourth parallel are hot and humid during the summer, they generally have lower yearly temperature averages (from 20 to 24 °C) because of more moderate conditions during the winter.
Many large cities in Mexico are located in the Valley of Mexico or in adjacent valleys with altitudes generally above 2,000 m, this gives them a year-round temperate climate with yearly temperature averages (from 16 to 18 °C) and cool nighttime temperatures throughout the year. Many parts of Mexico, particularly the north have a dry climate with sporadic rainfall while parts of the tropical lowlands in the south average more than 200 cm of annual precipitation.
Biodiversity
A Lepisosteus, one of the endemic species of MexicoMexico is one of the 17 megadiverse countries of the world. With over 200,000 different species, Mexico is home of 10–12% of the world's biodiversity. Mexico ranks first in biodiversity in reptiles with 707 known species, second in mammals with 438 species, fourth in amphibians with 290 species, and fourth in flora, with 26,000 different species. Mexico is also considered the second country in the world in ecosystems and fourth in overall species. Approximately 2,500 species are protected by Mexican legislations. The Mexican government created the National System of Information about Biodiversity, in order to study and promote the sustainable use of ecosystems.
In Mexico, 170,000 square kilometres are considered "Protected Natural Areas." These include 34 reserve biospheres (unaltered ecosystems), 64 national parks, 4 natural monuments (protected in perpetuity for their aesthetic, scientific or historical value), 26 areas of protected flora and fauna, 4 areas for natural resource protection (conservation of soil, hydrological basins and forests) and 17 sanctuaries (zones rich in diverse species).