The geological history of Costa Rica began more than 200 million years ago. The Orogeny process (the process of building mountains) began with volcanic activities, accompanied by oceanic outbursts and submarine ridges. One result of this process is an archipelago facing east, known as the outer arch located on the Nicoya Peninsula, Herradura Beach, the Osa Peninsula, and at Punta Burica. Due to the intense volcanic activity, the erosion processes increased in the sedimentation of these areas. About sixty million years ago, during the Lower and Middle Eocene epoch (main division of the geological time scale and the second epoch of the Paleocene period in the Cenozoic era), the entirety of the outer arc almost disappeared, many islands known as Guanarivas.
About 25 million years ago, during the Oligocene, these islands disappeared into the ocean and were covered by detritus material as a result of degradation and subsequent sedimentation. Due to intense volcanism, it produced the Aguacate Mountain and the Talamanca mountain range. As the mountains rose, they reached the heights of the inner arc followed later by the origin of the Cordillera Volcánica Central and the Cordillera de Guanacaste. Therefore, the conformation of the territory that Costa Rica occupies today has lasted approximately 8 to 10 million years, since the increase in geological structures occurs at a rate of 10 mm per year. When the formation of the isthmus between the Continents of South and North America over 3 million years ago occurred due to the shifting of tectonic plates and volcanism, it facilitated the migration of the majority of organisms from both Continents that accounts for the large diversity of life extant throughout much of Central America, especially here in Costa Rica. For such a relatively small region it is truly amazing that Costa Rica harbors nearly 5% of the world’s biodiversity. Biological diversity embraces all plants, animals, fungi, microorganisms, as well as the ecosystems and ecological processes that they are an integral part of. Accounting for this vast richness is the wide variety of habitat systems such as tropical wet forests, cloud forests, dry forests, moist forests, premontane and lower montane rain forests, and subalpine (paramo) among others. Each of these environments is defined according to, for example, how much rain they receive, amount of sunshine, temperature due to elevation, soil conditions, topography and types of plants. With regards to estimates on the number of species found in Costa Rica, insects dominate with over 35,000 currently identified, of which 1500 are butterflies and 12000 are moths; more than 12,000 species of vascular plants among which are about 800 species of ferns, nearly 2000 species of orchids, 30 species of heliconias, and 2000 species of bromeliads; amphibians number 175 species, about 85% which are frogs; 225 are reptiles, of which 70 species are lizards, 120 snakes (about 20 poisonous), 5 species of marine turtles that nest here in Costa Rica, and 2 crocodilians, the spectacled caiman and american crocodile; mammals account for around 250 species, more than half being bats, and birds represent over 900 species with over 600 that are residents and more than 200 migratorial. No doubt the aforementioned estimates in some instances will increase over time as new species are discovered, especially in the more remote regions of Costa Rica. All told, there are 15 wetland/mangrove areas, 26 national parks, 11 forest reserves, 58 wildlife refuges, 7 wildlife sanctuaries and 8 biological reserves in addition to numerous privately-owned protected areas.
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