In the context of the recent African origin of modern humans , the Southern Dispersal scenario (also the coastal migration or great coastal migration ) refers to the early migration along the southern coast of Asia, from the Arabian Peninsula via Persia and India to Southeast Asia and Oceania . Alternative names include the " southern coastal route " or " rapid coastal settlement ", with later descendants of those migrations eventually colonizing the rest of Eastern Eurasia, the remainder of Oceania, and the Americas.
38-417: According to this thesis, the dispersal was possible thanks to the development of a multipurpose subsistence strategy, based on the collection of organisms, fish, crustaceans, molluscs, algae, which are part of the biotic communities of the intertidal zone, the transition ecosystem between land and sea between the upper limit of high tides and the lower limit of low tides. - In support of this hypothesis there are
76-477: A Romance loanword into Primitive Germanic that has its origins in the Latin forms clivus / clevus ("slope" or "hillside"). Given that a cliff does not need to be exactly vertical, there can be ambiguity about whether a given slope is a cliff or not and also about how much of a certain slope to count as a cliff. For example, given a truly vertical rock wall above a very steep slope, one could count just
114-505: A fairly stringent notion of cliff, as the 1,340 m figure refers to a nearly vertical headwall of two stacked pillars; adding in a very steep approach brings the total drop from the East Face precipice to the nearby Dunge Glacier to nearly 2,000 m. The location of the world's highest sea cliffs depends also on the definition of 'cliff' that is used. Guinness World Records states it is Kalaupapa, Hawaii , at 1,010 m high. Another contender
152-481: A narrow strip, such as in Pacific islands that have only a narrow tidal range, or can include many meters of shoreline where shallow beach slopes interact with high tidal excursion. The peritidal zone is similar but somewhat wider, extending from above the highest tide level to below the lowest. Organisms in the intertidal zone are well-adapted to their environment, facing high levels of interspecific competition and
190-511: Is advanced through activities including harvesting fisheries with drag nets and a neglect of the sensitivity of intertidal zones. Cliff In geography and geology, a cliff or rock face is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion , with the effect of gravity . Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually composed of rock that
228-526: Is also a great biodiversity. Organisms in this zone generally are not well adapted to periods of dryness and temperature extremes. Some of the organisms in this area are abalone , sea anemones , brown seaweed , chitons , crabs , green algae , hydroids , isopods , limpets , mussels , nudibranchs , sculpin , sea cucumber , sea lettuce , sea palms , starfish , sea urchins , shrimp , snails , sponges , surf grass , tube worms , and whelks . Creatures in this area can grow to larger sizes because there
266-441: Is more available energy in the localized ecosystem. Also, marine vegetation can grow to much greater sizes than in the other three intertidal subregions due to the better water coverage. The water is shallow enough to allow plenty of sunlight to reach the vegetation to allow substantial photosynthetic activity, and the salinity is at almost normal levels. This area is also protected from large predators such as fish because of
304-558: Is overhanging. This is commonly regarded as being the largest vertical drop on Earth [1] ot:leapyear at 1,250 m (4,100 ft). of Baffin Island , rises 4,300 ft above the flat frozen fjord, although the lower portion of the face breaks from the vertical wall with a series of ledges and buttresses. Other notable cliffs include: Above Sea Above Land Above Sea Above Land Submarine Above Sea Above Land Cliff landforms provide unique habitat niches to
342-413: Is possible to watch ecological succession over years rather than decades. The burrowing invertebrates that make up large portions of sandy beach ecosystems are known to travel relatively great distances in cross-shore directions as beaches change on the order of days, semilunar cycles, seasons, or years. The distribution of some species has been found to correlate strongly with geomorphic datums such as
380-810: Is primarily linked to the Initial Upper Paleolithic expansion of modern humans and "ascribed to a population movement with uniform genetic features and material culture" ( Ancient East Eurasians ), which was the major source for the peopling of the Asia–Pacific region. While certain Initial Upper Paleolithic populations represented by specimens found in Central Asia and Europe , such as the Ust'-Ishim man , Bacho Kiro cave or Oase 2 , are inferred to have used inland routes,
418-422: Is resistant to weathering and erosion. The sedimentary rocks that are most likely to form cliffs include sandstone , limestone , chalk , and dolomite . Igneous rocks such as granite and basalt also often form cliffs. An escarpment (or scarp) is a type of cliff formed by the movement of a geologic fault , a landslide, or sometimes by rock slides or falling rocks which change the differential erosion of
SECTION 10
#1732765483374456-577: Is the New Zealand foreshore and seabed controversy . In legal discussions, the foreshore is often referred to as the wet-sand area . For privately owned beaches in the United States , some states such as Massachusetts use the low-water mark as the dividing line between the property of the State and that of the beach owner; however the public still has fishing, fowling, and navigation rights to
494-486: Is the north face of Mitre Peak , which drops 1,683 m to Milford Sound , New Zealand. These are subject to a less stringent definition, as the average slope of these cliffs at Kaulapapa is about 1.7, corresponding to an angle of 60 degrees, and Mitre Peak is similar. A more vertical drop into the sea can be found at Maujit Qaqarssuasia (also known as the ' Thumbnail ') which is situated in the Torssukátak fjord area at
532-506: Is the part of the littoral zone within the tidal range . This area can include several types of habitats with various species of life , such as sea stars , sea urchins , and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the littoral zone or seashore , although those can be defined as a wider region. The intertidal zone also includes steep rocky cliffs , sandy beaches , bogs or wetlands (e.g., vast mudflats ). This area can be
570-628: The Bab-el-Mandeb strait. It has been estimated that from a population of 2,000 to 5,000 individuals in Africa, only a small group, possibly as few as 150 to 1,000 people, crossed the Red Sea . The group would have travelled along the coastal route around Arabia and Persia to India relatively rapidly, within a few thousand years. From India, they would have spread to Southeast Asia (" Sundaland ") and Oceania (" Sahul "). The southern route dispersal
608-765: The Sam Ford Fjord , or others in remote areas of Greenland may be higher. The highest cliff in the solar system may be Verona Rupes , an approximately 20 km (12 mi) high fault scarp on Miranda , a moon of Uranus. The following is an incomplete list of cliffs of the world. Above Sea Above Land Several big granite faces in the Arctic region vie for the title of 'highest vertical drop on Earth', but reliable measurements are not always available. The possible contenders include (measurements are approximate): Mount Thor , Baffin Island , Canada; 1,370 m (4,500 ft) total; top 480 m (1600 ft)
646-442: The sea , which is actively moved to the zone by tides. The edges of habitats, in this case the land and sea, are themselves often significant ecosystems , and the littoral zone is a prime example. A typical rocky shore can be divided into a spray zone or splash zone (also known as the supratidal zone ), which is above the spring high-tide line and is covered by water only during storms, and an intertidal zone, which lies between
684-426: The splash zone (the region above the highest still-tide level, but which receives wave splash). On shores exposed to heavy wave action , the intertidal zone will be influenced by waves, as the spray from breaking waves will extend the intertidal zone. Depending on the substratum and topography of the shore, additional features may be noticed. On rocky shores , tide pools form in depressions that fill with water as
722-461: The L. 2971/01, the foreshore zone is defined as the area of the coast that might be reached by the maximum climbing of the waves on the coast (maximum wave run-up on the coast) in their maximum capacity (maximum referring to the "usually maximum winter waves" and of course not to exceptional cases, such as tsunamis ). The foreshore zone, a part of the exceptions of the law, is public, and permanent constructions are not allowed on it. In Italy, about half
760-592: The ancestors of all modern East Eurasian populations are inferred to have used the Southern dispersal route through South Asia , where they subsequently diverged rapidly and gave rise to modern populations in Eastern Eurasia, Oceania, and the Americas. Intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it
798-505: The ecosystems, yet forty-four percent of respondents state that there is a fair amount of knowledge used in those regions for fisheries. Intertidal zones are sensitive habitats with an abundance of marine species that can experience ecological hazards associated with tourism and human-induced environmental impacts . A variety of other threats that have been summarized by scientists include nutrient pollution , overharvesting , habitat destruction , and climate change . Habitat destruction
SECTION 20
#1732765483374836-482: The formation of sea cliffs along a receding coastline. The British Ordnance Survey distinguishes between around most cliffs (continuous line along the topper edge with projections down the face) and outcrops (continuous lines along lower edge). Cliff comes from the Old English word clif of essentially the same meaning, cognate with Dutch, Low German, and Old Norse klif 'cliff'. These may in turn all be from
874-435: The high and low tidal extremes. Along most shores , the intertidal zone can be clearly separated into the following subzones: high tide zone, middle tide zone, and low tide zone. The intertidal zone is one of a number of marine biomes or habitats , including estuaries , the neritic zone , the photic zone , and deep zones . Marine biologists divide the intertidal region into three zones (low, middle, and high), based on
912-590: The high tide strand and the water table outcrop. Since the foreshore is alternately covered by the sea and exposed to the air, organisms living in this environment must be adapted to both wet and dry conditions. Intertidal zone biomass reduces the risk of shoreline erosion from high intensity waves. Typical inhabitants of the intertidal rocky shore include sea urchins , sea anemones , barnacles , chitons , crabs , isopods , mussels , starfish , and many marine gastropod molluscs such as limpets and whelks . Sexual and asexual reproduction varies by inhabitants of
950-420: The intertidal zones. Humans have historically used intertidal zones as foraged food sources during low tide . Migratory birds also rely on intertidal species for feeding areas because of low water habitats consisting of an abundance of mollusks and other marine species. As with the dry sand part of a beach, legal and political disputes can arise over the ownership and use of the foreshore. One recent example
988-407: The littoral zone. With the intertidal zone's high exposure to sunlight , the temperature can range from very hot with full sunshine to near freezing in colder climates. Some microclimates in the littoral zone are moderated by local features and larger plants such as mangroves . Adaptations in the littoral zone allow the utilization of nutrients supplied in high volume on a regular basis from
1026-439: The overall average exposure of the zone. The low intertidal zone, which borders on the shallow subtidal zone, is only exposed to air at the lowest of low tides and is primarily marine in character. The mid intertidal zone is regularly exposed and submerged by average tides. The high intertidal zone is only covered by the highest of the high tides, and spends much of its time as terrestrial habitat. The high intertidal zone borders on
1064-477: The presence and dispersal of mtDNA haplogroup M and haplogroup N , as well as the specific distribution patterns of Y-DNA haplogroup F (ancestral to O, N, R, Q), haplogroup C and haplogroup D , in these regions. The theory proposes that early modern humans , some of the bearers of mitochondrial haplogroup L3 , arrived in the Arabian peninsula about 70,000-50,000 years ago, crossing from East Africa via
1102-420: The rapidly changing conditions that come with the tides . The intertidal zone is also home to several species from many different phyla ( Porifera , Annelida , Coelenterata , Mollusca , Arthropoda , etc.). The water that comes with the tides can vary from brackish waters , fresh with rain , to highly saline and dry salt , with drying between tidal inundations. Wave splash can dislodge residents from
1140-563: The remains found on an ancient Pleistocene reef, now emerged, near the locality of Abdur in Eritrea. Its rocks are the result of the compaction of marine debris about 125,000 years ago and contain fossil remains of a complex biotic community of the coast of the time: large colonies of corals, oyster shells, large clams and other bivalve molluscs, gastropods and echinoderms. A group of geologists and paleontologists found many blades and tools made of obsidian, quartz and fine volcanic stone, mixed with
1178-409: The remains of shells. This would prove that over 100,000 years ago human populations of Homo sapiens exploited the intertidal zone for food purposes. The coastal route theory is primarily used to describe the initial peopling of West Asia , India , Southeast Asia , New Guinea , Australia , Near Oceania , and East Asia beginning between roughly 70,000 and 50,000 years ago. It is linked with
Southern Dispersal - Misplaced Pages Continue
1216-442: The rock layers. Most cliffs have some form of scree slope at their base. In arid areas or under high cliffs, they are generally exposed jumbles of fallen rock. In areas of higher moisture, a soil slope may obscure the talus . Many cliffs also feature tributary waterfalls or rock shelters . Sometimes a cliff peters out at the end of a ridge, with mushroom rocks or other types of rock columns remaining. Coastal erosion may lead to
1254-551: The rock wall or the combination. Listings of cliffs are thus inherently uncertain. Some of the largest cliffs on Earth are found underwater. For example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench . According to some sources, the highest cliff in the world, about 1,340 m high, is the east face of Great Trango in the Karakoram mountains of northern Pakistan. This uses
1292-528: The shoreline is owned by the government but leased to private beach clubs called lidos. In the East African and West Indian Ocean, intertidal zone management is often neglected of being a priority due to there being no intent for collective economic productivity. According to workshops performing questionaries, it is stated that eighty-six percent of respondents believe mismanagement of mangrove and coastal ecosystems are due to lack of knowledge to steward
1330-420: The tide rises. Under certain conditions, such as those at Morecambe Bay , quicksand may form. This subregion is mostly submerged – it is only exposed at the point of low tide and for a longer period of time during extremely low tides. This area is teeming with life; the most notable difference between this subregion and the other three is that there is much more marine vegetation, especially seaweeds . There
1368-504: The very tip of South Greenland and drops 1,560 m near-vertically. Considering a truly vertical drop, Mount Thor on Baffin Island in Arctic Canada is often considered the highest at 1370 m (4500 ft) high in total (the top 480 m (1600 ft) is overhanging), and is said to give it the longest vertical drop on Earth at 1,250 m (4,100 ft). However, other cliffs on Baffin Island, such as Polar Sun Spire in
1406-613: The wave action and the relatively shallow water. The intertidal region is an important model system for the study of ecology , especially on wave-swept rocky shores. The region contains a high diversity of species, and the zonation created by the tides causes species ranges to be compressed into very narrow bands. This makes it relatively simple to study species across their entire cross-shore range, something that can be extremely difficult in, for instance, terrestrial habitats that can stretch thousands of kilometres. Communities on wave-swept shores also have high turnover due to disturbance, so it
1444-645: The zone between low and high water. Other states such as California use the high-water mark. In the United Kingdom , the foreshore is generally deemed to be owned by the Crown , with exceptions for what are termed several fisheries , which can be historic deeds to title, dating back to King John 's time or earlier, and the Udal Law , which applies generally in Orkney and Shetland . In Greece , according to
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