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Arctic ecology is the scientific study of the relationships between biotic and abiotic factors in the arctic, the region north of the Arctic Circle (66 33â€™). This is a region characterized by stressful conditions as a result of extreme cold, low precipitation, a limited growing season (50â€“90 days) and virtually no sunlight throughout the winter. The Arctic consists of taiga (or boreal forest) and tundrabiomes, which also dominate very high elevations, even in the tropics. Sensitive ecosystems exist throughout the Arctic region, which are being impacted dramatically by global warming.
To understand Arctic ecology, it is important to consider both the terrestrial and oceanic aspects of the region. A few important parts of this environment are sea ice and permafrost.
Sea ice is frozen seawater that moves with oceanic currents; it provides important habitat and a resting place for animals, particularly during the winter months. Over time, small pockets of salty seawater get trapped in the ice, and the salt is squeezed out. This causes the ice to become progressively less salty. Sea ice persists throughout the year, but there is less ice available during summer months.
Large portions of the land are also frozen during the year. Permafrost is substrate that has been frozen for a minimum of 2 years. There are two types of permafrost: discontinuous and continuous. Discontinuous permafrost is found in areas where the mean annual air temperature is only slightly below freezing (0|Â°C|Â°F|0|abbr=on|lk=on|disp=s); this forms in sheltered locations. In areas where the mean annual soil surface temperature is below -5|Â°C|Â°F|0|abbr=on|lk=off, continuous permafrost forms. This is not limited to sheltered areas and ranges from a few inches below the surface to over 300|m|ft|-2|abbr=on|lk=off deep. The top layer is called the active layer. It thaws in the summer and is critical to plant life.
Moisture and temperature are major physical drivers of natural ecosystems. The more arid and colder conditions found at higher northern latitudes (and high elevations elsewhere) support tundra and boreal forests. The water in this region is generally frozen and evaporation rates are very low. Species diversity, nutrient availability, precipitation, and average temperatures increase as you move from the tundra to boreal forests and then to deciduoustemperate ecosystems, which are found south of these Arctic biomes.
Tundra is found from 55 Â° to 80Â° N latitude in North America, Eurasia and Greenland. It can be found at lower latitudes at high elevations as well. The average temperature is -34|Â°C|Â°F|0|abbr=on|lk=off; during the summer it is less than 10|Â°C|Â°F|abbr=on|lk=off. Average precipitation ranges from 10|to|50|cm|in|0|abbr=on|lk=off, and the permafrost is 400|-|600|m|ft|-2|abbr=on|lk=off thick. Plant species supported by tundra have small leaves, are short (74 mm to <5 m), tend to be deciduous, have a high ratio of roots to shoots, and are composed mainly of perennial forbs, dwarf shrubs, grasses, lichens, and mosses.
In comparison to tundra, boreal forest has a longer and warmer growing season and supports larger species diversity, an increase in canopy height, vegetation density, and biomass. Boreal conditions can be found across northern North America and Eurasia. The boreal forests in the interior of the continents grow on top of permafrost due to very cold winters (see drunken trees), while much of the boreal forest has patchy permafrost or lack permafrost completely. The short (3â€“4 month) growing season in boreal forests is sustained by greater levels of rainfall (between 30|and|85|cm|in|abbr=on|lk=off|disp=s per year) than the tundra receives; This biome is dominated by closed canopy forests of evergreen conifers, especially spruces, fir, pine and tamarack with some diffuse-porous hardwoods. Shrubs, herbs, ferns, mosses, and lichens are also important species. Stand-replacing crown fires are very important to this biome, occurring as frequently as every 50â€“100 years in some parts.
Adaptations to conditions
Humans living in the Arctic region generally rely on warm clothing and buildings to protect them from the elements. Acclimatization, or the adjustment to new conditions, appears to be the most common form of adaptation to cold environments. No genetic advantage has been found when different people groups or races are compared. There is no evidence that fat is grown in response to cold, although its presence is advantageous. Amazingly, most people living in the Arctic region live a lifestyle very connected to the environment, spending significant time outside and depending heavily on hunting and fishing.
Animals that are active in the winter have adaptations for surviving the intense cold. A common example is the presence of strikingly large feet in proportion to body weight. These act like snowshoes, and can be found on animals like the snowshoe hare and caribou. Many of the animals in the Arctic are larger than their temperate counterparts (Bergmannâ€™s rule), taking advantage of the smaller ratio of surface area to volume that comes with increasing size. This increases the ability to conserve heat. Layers of fat, plumage, and fur are also very effective insulators to help retain warmth and are common in Arctic animals including polar bears and marine mammals. Some animals also have digestive adaptations to improve their ability to digest woody plants either with or without the aid of microbial organisms. This is highly advantageous during the winter months when most soft vegetation is beneath the snow pack.
Not all Arctic animals directly face the rigors of winter. Many migrate to
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Answers:1.) As a population reaches its carrying capacity, there may be an increase in competition for: D. all of the above 2. The relationship between a predactor and its prey is best illustrated by B.) a lion eating a zebra 3. Which of the following usually results when members of different species require the same food and space? D.) interspecific competition 4. The relationship between flowering plants and the bees that pollinate them is an example of: C.) mutualism 5. Cattle egrets are birds that mostly feed on insects that have been disturbed by grazing cattle. The cattle are neither helped nor harmed by the presence of the egrets. The relationship is an example of: A.) commensalism 6. A dog providing nutrients and shelter for the tapeworm living in it intestines is an example of: D.) parasitism 7. A sheep eating the same grass as a cow is an example of: B.) competition 8. An ant keeps predators away from the acacia tree. The acacia provides shelter and food for the ant. This is an example of: B.) mutualism 9. An tree provides nutrients and a sunlit location for the orchid living on it. This is an example of: A.) commensalism orchids are epiphytes - not actually parasites b/c they don't harm the tree they grow on, but they don't help it either 10. Major ecosystem that occur over wide areas of land are called B.) biomes 11. A.) temperate deciduous forest Biome 4:B.) tropical rain forestBiome 3 C.) taiga Biome 5: D.) tundra Biome 1 12. The biome that makes up most of the central part of the continental U.S. is: B.) temperate grassland 13. Which of the following animals is most likely to live in a temperate deciduous forest? C.) deer 14. The specific physical locations of where a given species lives is called its: A.) habitat 15. When an organism dies, the nitrogen in its body C.) is released by the action of decomposers Answer key for 16-19 C.) desert 16.) Long, cold, moist winters and short summers are typical of the biome dominated by gynosperms.E.) taiga 17.) A prolonged, relatively mild period with ample precipitation alternates with a cold period when plants become dormant A.) deciduous forest 18.) This biome has the greatest diversity of speciesB.) tropical rain forest 19.) This biome is dominated by dwarf shrubs, grasses, and sedges that can tolerate long dark winters.D.) tundra
Answers:thats not all that nice for a top contributer to say that :/ well ill cover ya. 1.autotrophs are basically plants. they make their own food from energy from the sun. Heterotrophs are organisms that get there food consuming others. 2.Autotrophs are on the lowest level of ecological pyramids because they are the main source of energy for all the other animals and have 100% energy from the sun. Ecological pyramids are based upon energy. The organism with the most enery is at the bottom and the one with the least is at the top. When animals eat other animals, they are only getting 10% of the energy of the animal they consumed. 3.for the nitrogen cycle just follow the arrows on this diagram and explain each arrow movment http://kywater.org/ww/ramp/rmfig3.jpg 4. The food chain is basically a diagram that shows the movment of energy through animals
Answers:Biodiversity maintains the "chemistry" of the environment, by recycling nutrients, changing the forms that energy takes, and converting waste to other forms. For invasive species, research the cane toad in Australia or kudzu in the US. Predator populations maintain healthy populations of prey organisms by consuming prey and suppressing population expansion that an environment can't support. Evolutionarily, one might say that predators eat the non-fit, allowing those individuals with traits more likely to give them a survival and reproductive benefit to survive. Carbon dioxide may be removed from the atmosphere by plants via photosynthesis or via weathering (C02 absorption into surface waters... look up carbonic acid or bicarbonate formation). For the greater variety in a food web question, think about what happens when the invasive species you researched eliminate another group (So when the invading species kills off animal A, what happens to the animals that eat animal A? What would happen if they had other stuff that they could eat too?) Hope some of this helped for a couple of them!
Answers:Symbiosis means living together in a close ecological relationship but always inter-specific-it occurs only between different species. Fish can be in two symbiotic relationships by having internal parasites in a parasitic symbiosis and have cleaner fish in a mutual symbiosis. In mutualism both species benefit but in parasitism one species benefits at the expense of the other. In commensalism, one species benefits and the other remains unaffected. Barnacles and whales live in a commensal relationship. Some barnacle species are not such easy partners; the Sacculina is a parasitic barnacle on crabs. http://books.google.com/books?id=X8M7fsyvQo4C&pg=PA205&lpg=PA205&dq=symbiosis+sacculina+barnacle+crab&source=bl&ots=UensCHDFHQ&sig=NY_rPVKgfSWlLDY98Z2Q5dkZq3Y&hl=en&ei=kj15SqjuE4vssQOPhP3fBA&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=symbiosis%20sacculina%20barnacle%20crab&f=false In competition, neither species benefits. This is seen when both milk fish and tilapia species feed on the same algae source. Rhizobium are in a symbiosis with legumes like peanuts that is a highly adapted and regulated mutualism. The carabao water buffalo exist with cattle egrets in commensal relationships. The buffalo grazes, disturbing insects for the bird to eat. The bird will perch on the buffalo and also hunt for skin parasites like ticks. http://en.wikipedia.org/wiki/Cattle_Egret A very large venus fly trap can eat a small frog as in the youtube video below, but this is not the typical relationship. http://www.youtube.com/watch?v=B8XQ20X_4s4