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GAARlandia
The Greater Antilles + Aves Ridge, also known as GAARlandia, is a hypothesized land bridge which is proposed to have connected the Greater Antilles to South America around 33 million years ago (mya). Animal and plant species are thought to have colonisation (biology), colonized the Caribbean Islands through biological dispersal, dispersal and vicariance, and the most prominent vicariance hypothesis involves colonization via GAARlandia. Proponents of the hypothesis cite studies of individual lineage (genetic), lineages, while critics point to a lack of geological evidence. Hypothesis The GAARlandia hypothesis was introduced by Ross MacPhee and Manuel Iturralde-Vinent in 1994. It posits that the North American plate, North American and South American plates compressed the Caribbean plate for 2 million years during the Eocene–Oligocene boundary (33 million years ago), which led the presently-submerged Aves Ridge in the eastern Caribbean Sea to rise and connect South America with Pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aves Ridge
The Aves Ridge is a ridge in the eastern Caribbean Sea. It runs in a north-south direction, approximately 250 km west of the Lesser Antilles Volcanic Arc. It is mostly under water, but it reaches the surface in the north as Aves Island and in the south as La Blanquilla Island. Most geologists believe that the Aves Ridge originated as a volcanic arc which is now extinct, though its width poses a problem; the date of its origin is generally placed in the Cretaceous. The GAARlandia hypothesis posits that the Aves Ridge was above sea level for a short time around 33 million years ago (around the Eocene–Oligocene boundary), allowing South American land animals to expand to the Greater Antilles The Greater Antilles is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, and Jamaica, together with Navassa Island and the Cayman Islands. Seven island states share the region of the Greater Antille .... References Underwater ridges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Bridge
In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonize new lands. A land bridge can be created by marine regression, in which sea levels fall, exposing shallow, previously submerged sections of continental shelf; or when new land is created by plate tectonics; or occasionally when the sea floor rises due to post-glacial rebound after an ice age. Prominent examples Former land bridges * The Bassian Plain, which linked Australia to Tasmania * The Antarctic Land Bridge, which connected South America, Antarctica, and Australia during the Late Cretaceous and Early Paleogene * The Bering Land Bridge (aka Beringia), which intermittently connected Alaska (Northern America) with Siberia (North Asia) as sea levels rose and fell under the effect of ice ages * GAARlandia, a hypothesized land bridge which potentially connected the Greater Antilles with South America d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Community
The scientific community is a diverse network of interacting scientists. It includes many "working group, sub-communities" working on particular scientific fields, and within particular institutions; interdisciplinary and cross-institutional activities are also significant. Objectivity (philosophy), Objectivity is expected to be achieved by the scientific method. Peer review, through discussion and debate within journals and conferences, assists in this objectivity by maintaining the quality of research methodology and interpretation of results. History of scientific communities The eighteenth century had some societies made up of men who studied nature, also known as natural philosophy, natural philosophers and natural history, natural historians, which included even amateurs. As such these societies were more like local clubs and groups with diverse interests than actual scientific communities, which usually had interests on specialized disciplines. Though there were a few olde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Controversy
Sustained scientific debate, sometimes scientific controversy or persistent disagreement, is any a substantial disagreement among scientists. A scientific controversy may involve issues such as the interpretation of data, which ideas are most supported by evidence, and which ideas are most worth pursuing. Controversies between scientific and non-scientific ideas are not within the realm of science and are not true scientific controversies. A genuine scientific controversy entails an ongoing discussion within the wider scientific community. Well known examples include the debate over the existence of the atom that lasted until the turn of the 20th century, the Bohr–Einstein debates, the linguistics wars, or the debate over the causes of ADHD. Academic debate Scientific discourse happens almost exclusively in writing. Before speaking on a conference, scientists will have written on their subject. Everything prior to writing is usually considered scientific research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Dispersal
Oceanic dispersal is a type of biological dispersal that occurs when Terrestrial animal, terrestrial organisms transfer from one land mass to another by way of a sea crossing. Island hopping is the crossing of an ocean by a series of shorter journeys between islands, as opposed to a single journey directly to the destination. Often this occurs via large rafts of floating vegetation such as are sometimes seen floating down major rivers in the tropics and washing out to sea, occasionally with animals trapped on them. Dispersal via such a raft is sometimes referred to as a rafting event. Colonization of land masses by plants can also occur via long-distance oceanic dispersal of floating seeds. History Rafting has played an important role in the colonization of isolated land masses by mammals. Prominent examples include Madagascar, which has been isolated for ~120 million years (Year#SI prefix multipliers, Ma), and South America, which was isolated for much of the Cenozoic. Both lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrates
Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebrata with some 65,000 species, by far the largest ranked grouping in the phylum Chordata. The vertebrates include mammals, birds, amphibians, and various classes of fish and reptiles. The fish include the jawless Agnatha, and the jawed Gnathostomata. The jawed fish include both the Chondrichthyes, cartilaginous fish and the Osteichthyes, bony fish. Bony fish include the Sarcopterygii, lobe-finned fish, which gave rise to the tetrapods, the animals with four limbs. Despite their success, vertebrates still only make up less than five percent of all described animal species. The first vertebrates appeared in the Cambrian explosion some 518 million years ago. Jawed vertebrates evolved in the Ordovician, followed by bony fishes in the Devonian. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Level
Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised geodetic datumthat is used, for example, as a chart datum in cartography and Navigation, marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to Calibration, calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead a long-term average of tide gauge readings at a particular reference location. The term ''above sea level'' generally refers to the height above mean sea level (AMSL). The term APSL means above present sea level, comparing sea levels in the past with the level today. Earth's radius at sea level is 6,378.137 km (3,963.191 mi) at the equator. It is 6,356.752 km (3,94 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual Climate of Antarctica#Precipitation, precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the Lowest temperature recorded on Earth, lowest measured temperature on Earth, . The coastal regions can reach temperatures over in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Ice Sheet
The Antarctic ice sheet is a continental glacier covering 98% of the Antarctic continent, with an area of and an average thickness of over . It is the largest of Earth's two current ice sheets, containing of ice, which is equivalent to 61% of all fresh water on Earth. Its surface is nearly continuous, and the only ice-free areas on the continent are the dry valleys, nunataks of the Antarctic mountain ranges, and sparse coastal bedrock. However, it is often subdivided into the East Antarctic ice sheet (EAIS), West Antarctic ice sheet (WAIS), and Antarctic Peninsula (AP), due to the large differences in topography, ice flow, and glacier mass balance between the three regions. Because the East Antarctic ice sheet is over 10 times larger than the West Antarctic ice sheet and located at a higher elevation, it is less vulnerable to climate change than the WAIS. In the 20th century, EAIS had been one of the only places on Earth which displayed limited cooling instead of warming, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jamaica
Jamaica is an island country in the Caribbean Sea and the West Indies. At , it is the third-largest island—after Cuba and Hispaniola—of the Greater Antilles and the Caribbean. Jamaica lies about south of Cuba, west of Hispaniola (the island containing Haiti and the Dominican Republic), and southeast of the Cayman Islands (a British Overseas Territories, British Overseas Territory). With million people, Jamaica is the third most populous English-speaking world, Anglophone country in the Americas and the fourth most populous country in the Caribbean. Kingston, Jamaica, Kingston is the country's capital and largest city. The indigenous Taíno peoples of the island gradually came under Spanish Empire, Spanish rule after the arrival of Christopher Columbus in 1494. Many of the indigenous people either were killed or died of diseases, after which the Spanish brought large numbers of Africans to Jamaica as slaves. The island remained a possession of Spain, under the name Colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
