A:Human activity affects ecosystems in a wide variety of ways, but it primarily does so through agriculture, habitat destruction, water use and fishing. Whenever humans enter a habitat, they tend to reshape it to fit their own needs, destroying the resources that other animals use, which drives them out. The overuse of water drains natural aquifers and alters the local water table, and pollution can negatively affect wildlife populations.
A:The two main types of glaciers are continental glaciers and alpine glaciers. Continental glaciers are also known as ice sheets because their form and flow are not significantly affected by underlying geographic formations. Alpine glaciers form on mountains and flow down mountain valleys.
A:Fresh water is turned into an iceberg by the splitting or calving of glaciers. Bergs also vary wildly in shape and can be steep or irregular with rounded or flat tops. Because wind and water erode them, they constantly shift shape.
A:The earth's magnetic field causes a compass to point north, as compasses are powered by magnets. The magnets inside compasses are drawn to the magnetic North Pole, which is about 1,000 miles south of the actual North Pole. Therefore, even though a compass always points north, it does not always point toward the true north.
A:The Earth is constantly spinning on its axis, allowing sunlight to shine on different areas of the Earth at different times of the day, creating daytime when the Sun hits a specific area. When the Sun is not shining on a specific area of the Earth, it is nighttime. Since the Sun does not hit all of the Earth at the same time, it is daytime in some parts of the world, while it is nighttime in others.
A:The term global winds refers to the six major wind belts that encircle the globe. Local winds, however, are the winds, or breezes, that are stirred up by the temperatures and topographical features of a small region or area. This is especially true of coastal areas.
A:The heat that radiates from the sun and heats up the land begins to heat up the air and then escapes into the atmosphere due to the lack of clouds and humidity. This is the main reason that deserts can be hot during the day but cold during the night.
A:In the field of ecology, a natural system is one that exists in nature, independent of any human involvement. The natural system consists of all the physical and biological materials and their intertwined processes
A:Striations are a common feature of rocks that have once been overlain by a moving glacier. The scratches on the rock face are generally straight and all are oriented in the same direction, matching the downhill flow of the ice.
A:In order, the steps of the water cycle are evaporation, condensation, sublimation, precipitation, transpiration, runoff and infiltration. Together, all of the steps help regulate the Earth’s water supply and climate.
A:Global winds refer to the pattern of air movement all around the globe, and they result from the fact that the Earth receives unequal heating from the sun. Not only does the tilt of the Earth's axis mean that different parts of the planet receive disparate amounts of sunlight, but the oceans and lands also heat at different rates. The imbalance in temperature makes heat move toward the poles, both in the wind and in ocean currents. When horizontal variances in air pressure take place as a result, wind occurs.
A:Rift valleys form when tectonic forces deep underground exert a pulling force on the terrain. In areas where this occurs, the land splits into a steep-walled valley with a flat floor. Rift valleys can be very narrow, especially early in their formation.
A:The average temperature range of the world's swamps is between 15 C and 35 C. Swamps fall into two categories: swamp forests and shrub swamps. Bogs are not true swamps because they are not forested, but they are often mislabeled as such.
A:Types of natural calamities include hurricanes, earthquakes and tsunamis. Often, these calamities are connected such that one sets off another, as with earthquakes and tsunamis. Natural calamities are differentiated from human-made calamities, such as industrial accidents.
A:Gold and platinum are the most ductile metals on the periodic table of elements. Metals like copper, iron, nickel, manganese, silver, iridium, osmium, tungsten, tantalum, hafnium, rhenium, tin and zirconium can be drawn into very long wires. An ounce of gold can be drawn into a wire 50 miles long.
A:Ecological balance is a theory stipulating that natural conditions, including numbers of various animal and plant species, remain stable on their own through variations over time. The theory, also known as balance of nature, also holds that natural equilibrium can be changed significantly by new species entering an ecosystem, the disappearance of some species, man-made changes to the environment or natural disasters.
A:Environmental factors refer to any element that might bring change to an existing environment. This include human factors such as litter that does not biodegrade, as well as such natural forces as the weather. One thing that is always true about the environment is that it is always in the state of change. Some of these shifts are easy to see, like an avalanche that happens on the side of a mountain as the result of traffic construction activity, while others are less obvious, such as sand finally becoming sandstone.