Raffi at 06:26, 7 April 2007

2007-04-07T06:26:21Z

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[[Image:Tropical-area-mactan-philippines.jpg|thumb|240px|left|A noontime scene from the [[Philippines]] on a day when the sun is almost directly overhead.]]
The '''tropics''' are the geographic region of the [[Earth]] centered on the [[equator]] and limited in [[latitude]] by the [[Tropic of Cancer]] in the northern hemisphere, at approximately 23°30' (23.5°) N latitude, and the [[Tropic of Capricorn]] in the southern hemisphere at 23°30' (23.5°) S latitude. This region is also referred to as the '''tropical zone''' and the '''torrid zone'''.

''(For the history of the term '''torrid zone''', see [[geographical zone]])''

[[Image:World map torrid.svg|thumb|right|World map with the tropics highlighted in red]]
This area includes all the areas of the Earth where the sun reaches a point directly overhead at least once during the solar year. (In the [[temperate zone]]s, north of the Tropic of Cancer and south of the Tropic of Capricorn, the sun never reaches an angle of 90° or directly overhead.) The word "tropics" comes from [[Greek language|Greek]] ''tropos'' meaning "turn", because the apparent position of the Sun oscillates between the two tropics with a period that defines the average length of a [[year]].

'''Tropical''' plants and animals are those species native to the tropics. ''Tropical'' is also sometimes used in a general sense for a [[tropical climate]], a [[climate]] that is warm to hot and moist year-round, often with the sense of lush vegetation. However, there are places in the tropics that are anything but "tropical" in this sense, with even [[alpine tundra]] and snow-capped peaks, including [[Mauna Kea]], [[Mount Kilimanjaro|Mt. Kilimanjaro]], and the [[Andes]] as far south as the northernmost parts of [[Chile]] and [[Argentina]]. Places in the tropics which are drier with low humidity but extreme heat are such as the [[Sahara|Sahara Desert]] and Central Africa and Northern Australian Outback.

==Tropical ecosystems==
Tropical ecosystems may consist of [[rainforests]], dry deciduous forests, spiny forests, [[desert]] and other habitat types. There are often significant areas of [[biodiversity]] and species [[endemism]] present particularly in [[rainforest]]s and dry deciduous forests. Some examples of important biodiversity and/or high endicism ecosystems are: [[Costa Rica]]n rainforests, [[Madagascar dry deciduous forests]], [[Waterberg Biosphere]] of [[South Africa]] and eastern [[Madagascar]] rainforests. Often the soils of tropical forests are low in [[nutrient]] content making them quite vulnerable to [[slash-and-burn]] techniques, which are sometimes an element of [[shifting cultivation]] agricultural systems.

In [[biogeography]], the tropics are divided into '''paleotropics''' (Africa, Asia and Australia) and '''[[neotropics]]''' (Central and South America). Together, they are sometimes referred to as the '''pantropics'''. The neotropic region should not be confused with the [[ecozone]] of the same name; in the Old World, this is unambiguous as the paleotropics correspond to the Afrotropical, Indomalayan, and partly the Australasian and Oceanic ecozones. The [[Capensis]] region of [[botany]] is not part of the tropics; it has a [[Mediterranean climate]].

==See also==
*[[Tropic of Cancer]]
*[[Tropic of Capricorn]]
*[[Geographical zone]]
*[[Equator]]

[[Category:Seasons]]

Tropics - Revision history

Raffi at 06:26, 7 April 2007