2.4 Biomes
2.4.1 - Define the term biome.
Biome is a collection of ecosystems that share similar climatic conditions and so give rise to similar vegetation patterns.
Biome is a collection of ecosystems that share similar climatic conditions and so give rise to similar vegetation patterns.
2.4.2 - Explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and any other biome.
Rain forests Distribution: Rain forests are mainly hot and wet areas with broadleaved evergreen forest. Usually located within 5 degrees north and south of the equator. Has high rainfall 2000-5000mm per year and temperature varies from 26C-28C. Structure: The highest levels of biodiversity. Plants compete for light and so grow tall to absorb sunlight. These high plants also provide habitat for higher trophic levels. Plants have shallow roots as most nutrients are near the surface so they have buttress roots to support them. We mainly see 4-5 layers of environment. Productivity: Produces 40% NPP of all terrestrial ecosystems. Growing season all year around. Fast rates of decomposition, respiration and photosynthesis. Rapid recycling of nutrients. Fast Growing plants |
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Tundra
Distribution: Tundras are treeless plains where subsoil is permanently frozen. Temperature and precipitation are both very low. Tundras have long and darks winters. Mainly located on the south of the Arctic ice cap and also small amounts in southern hemisphere. Structure: Tundra doesn’t have trees, but thick mat of low growing plants like small shrubs (soil is poor). These plants are adapted to extreme environments and develop underground storage organs. Animals also have thick fur and small ears to reduce heat loss. Low biodiversity – 900 species of plants compared with 40 000 or more in the amazon rainforest. Productivity: Productivity is very low. Decomposition process is very slow. |
Temperate Grassland
Temperate grasslands are flat areas dominated by grasses and herbaceous plants. These grasslands exist in centres of continents 40-60 North of Equator. Distribution: Grasslands are mostly everywhere in the world, in the centre of Australia and the United States, it could also be found in Africa and Asia. The center of Australia is mostly desert and grassland, where rainfall is really low and the temperature is average, but quite cold. So, low rainfall and cool temperature is the reason for their location. Structure: In grasslands mainly we have grazing animals, because the main producer is the grass, in the second trophic level there are grazing animals such as Kangaroos, bison, antelope. In the third trophic level wolves and coyotes positioned. Relative productivity is below average because of the reasons mentioned above. Productivity: |
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Deserts
Desert is the dry area full of sand, very hot in the day and cold at night. They are generally found 30 degrees North and South of the equator where dry air descends Distribution: Most deserts are in the middle of continents, e.g. Africa, Australia, little bit of USA and Asia. Deserts are placed in the continents above because in those areas there is the lowest rainfall annually and really hot temperature. Structure: Deserts are not known as very rich place in terms of animal species and plants, the main organisms in deserts are snakes, lizards, also cactus and little bushes. |