lunes, 3 de marzo de 2008

Biomes

What is a blog and what you use it for?
A blog is a Web site where you can rapidly express your opinions and interact with other users. The blog is mostly use to write about what ever theme that the user want to talk about. Online users could comment in your blog so you could improve your blog or discuss the information.

What is a biome?

A biome is a large geographical area characterized by certain types of plants and animals. A biome is defined by the complex interactions of plants and animals with the climate, geology (rock formations), soil types, water resources, and latitude (position north or south on the globe) of an area. The importance of biomes cannot be overestimated. Biomes have changed and moved many times during the history of life on Earth. More recently, human activities have drastically altered these communities. Thus, conservation and preservation of biomes should be a major concern to all. The six major types are: freshwater, marine, desert, forest, grasslands, and tundra.


Biomes in the world:
Rainforest Tundra Taiga


Desert Temperate Grasslands
  • There are two types of ecosystems:
  1. Freshwater that contains:

rivers and streams , ponds and lakes , and wetlands .

2. Marine that contains:

shorelines , temperate oceans , and tropical oceans .

Because we share the world with many other species of plants and animals, we must consider the consequences of our actions. Over the past several decades, increasing human activity has rapidly destroyed or polluted many ecological habitats throughout the world. It is important to preserve all types of biomes as each houses many unique forms of life. However, the continued heavy exploitation of certain biomes, such as the forest, freshwater, and marine, may have more severe implications.



GRASSLANDS
Grassland biomes are large, rolling terrains of grasses, flowers and herbs. Latitude, soil and local climates for the most part determine what kinds of plants grow in a particular grassland. A grassland is a region where the average annual precipitation is great enough to support grasses, and in some areas a few trees. The precipitation is so eratic that drought and fire prevent large forests from growing. Grasses can survive fires because they grow from the bottom instead of the top. Their stems can grow again after being burned off. The soil of most grasslands is also too thin and dry for trees to survive. There are two different types of grasslands; tall-grass, which are humid and very wet, and short-grass, which are dry, with hotter summers and colder winters than the tall-grass prairie. Grassland biomes can be found in the middle latitudes, in the interiors of continents. They can have either moist continental climates or dry subtropical climates. In the winter, grassland temperatures can be as low as -40° F, and in the summer it can be as high 70° F. There are two real seasons: a growing season and a dormant season.
The growing season is when there is no frost and plants can grow (which lasts from 100 to 175 days). During the dormant (not growing) season nothing can grow because its too cold. In tropical and subtropical grasslands the length of the growing season is determined by how long the rainy season lasts. But in the temperate grasslands the length of the growing season is determined by temperature. Plants usually start growing when the daily temperature reached about 50° F. In temperate grasslands the average rainfall per year ranges from 10-30 inches. In tropical and sub-tropical grasslands the average rainfall per year ranges from 25-60 inches per year The amount of rainfall is very important in determining which areas are grasslands because it's hard for trees to compete with grasses in places where the uppers layers of soil are moist during part of the year but where deeper layer of soil are always dry.
Common animals found in grasslands are elephants, bisons, kestrels, burrowing owls, collared pecarry, rabbits, snakes, llma, mouflon, leopard, wild board, etc.




RIVERS AND STREAMS


Rivers and streams mostly get started from mountainous ice and snow melting and springs. Ultimately, rivers and streams end up at the ocean or another waterway. Since this water is in constant motion, it is quite different in fauna and flora to that of lakes and ponds. animals and plants which thrive in lakes would have trouble surviving the colder water and limited shorelines of rivers. Some fish, such as river trout, and small scavengers such as crayfish can be found in various areas of the river; usually depending on water temperature and the exposure of a riverbank to sunlight. The colder areas are host to salmon and other more vigorous fish, whilst the warmer areas, rich in sediment and decaying matter are inhabited by catfish, carp, and other bottom feeders. River plants include floating weeds and algae, mostly found forming around rocks and submerged tree roots.
The area where freshwater meets saltwater, is called an estuary; this area usually features unique characteristics, trees and algae, seaweed, wetland flora, and various species of invertebrates, birds, reptiles and crustaceans congregate into a complex ecosystem, serving as a "trade center" to the world's aquatic biomes. Although there are many rivers and streams, these sources of running water account for a very small portion of the earth's total surface, just .3%.








TUNDRA


Tundra is the coldest of all the biomes. Tundra comes from the Finnish word tunturi, meaning treeless plain. It is noted for its frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons. Dead organic material functions as a nutrient pool. The two major nutrients are nitrogen and phosphorus. Nitrogen is created by biological fixation, and phosphorus is created by precipitation. Characteristics of tundra include: Extremely cold climate, Low biotic diversity, Simple vegetation structure, Limitation of drainage, Short season of growth and reproduction, Energy and nutrients in the form of dead organic material, and Large population oscillations. Tundra is separated into two types:
Arctic tundra and Alpine tundra.

Arctic tundra
Arctic tundra is located in the northern hemisphere, encircling the north pole and extending south to the coniferous forests of the taiga. The arctic is known for its cold, desert-like conditions. The growing season ranges from 50 to 60 days. The average winter temperature is -34° C (-30° F), but the average summer temperature is 3-12° C (37-54° F) which enables this biome to sustain life. Rainfall may vary in different regions of the arctic. Yearly precipitation, including melting snow, is 15 to 25 cm (6 to 10 inches). Soil is formed slowly. A layer of permanently frozen subsoil called permafrost exists, consisting mostly of gravel and finer material. When water saturates the upper surface, bogs and ponds may form, providing moisture for plants. There are no deep root systems in the vegetation of the arctic tundra, however, there are still a wide variety of plants that are able to resist the cold climate. There are about 1,700 kinds of plants in the arctic and subarctic, and these include: low shrubs, sedges, reindeer mosses, liverworts, grasses, 400 varieties of flowers, and crustiest and foliose lichen.
All of the plants are adapted to sweeping winds and disturbances of the soil. Plants are short and group together to resist the cold temperatures and are protected by the snow during the winter. They can carry out photosynthesis at low temperatures and low light intensities. The growing seasons are short and most plants reproduce by budding and division rather than sexually by flowering. The fauna in the arctic is also diverse:
Herbivorous mammals: lemmings, voles, caribou, arctic hares and squirrels
Carnivorous mammals: arctic foxes, wolves, and polar bears
Migratory birds: ravens, snow buntings, falcons, loons, ravens, sandpipers, terns, snow birds, and various species of gulls
Insects: mosquitoes, flies, moths, grasshoppers, black flies and arctic bumble bees
Fish: cod, flatfish, salmon, and trout
Animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer. Animals such as mammals and birds also have additional insulation from fat. Many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually oscillates.

Alpine tundra
Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. The growing season is approximately 180 days. The nighttime temperature is usually below freezing. Unlike the arctic tundra, the soil in the alpine is well drained. The plants are very similar to those of the arctic ones and include: tussock grasses, dwarf trees, small-leafed shrubs, and heaths.
Animals living in the alpine tundra are also well adapted:
Mammals: pikas, marmots, mountain goats, sheep, elk
Birds: grouselike birds
Insects: springtails, beetles, grasshoppers, butterflies









Conclusions
There exists a variety of biomes. The biomes are: tundra, taiga, rainforest, desert, grasslands, temperate, marine, and fresh water biomes (rivers and streams, tropical oceans, ponds and lakes, shorelines, wetlands, temperate oceans). Each biome is determine because of its vegetation, animals living there, and type of water (salty or not, river, lake, etc.). The biomes I talked about were grasslands, tundra, and rivers and streams. Grasslands are large terrains where the precipations is enough to support the grasses and animals. Rivers and streams are line cannals of non salty water that are formed by melting ice or that guides water from oceans to lakes, or lakes to other places. Tundra is refered to the most cold biomes of the world and there are two types the artic tundra, that is refered to the artic, and the alpine tundra that is refered to cold mountains.


How are biomes related to human action and ecologial impact?
I think biomes are related to human action and ecologial impact because humans have adapted its sources to live in each kind of biome, humans also have studied the biomes. Too, humans have tried to help the biomes when affected because of the human action or polution.
Comment - I really like making the blog even though we had a lot of work to do. I really had a hard time putting the pictures, finding a lot of information (rivers and streams I couldn't find much) but I love seeing all the biomes pictures. I know the blog is not well structed but I couldn't find the way to correct it.
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