Biome PSC CIRCLE PSC CIRCLE

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1 Biome 1. Terrestrial part of Bio sphere is divided into enormous regions which are characterized by specific species living there, called as Biomes. 2. The 2 most important climatic factors that determine a biome are temperature and precipitation. 3. A biome can have multiple ecosystems in it. 4. Not all scientist classify biome in the same way 5. The major biomes of the world are Tundra, Taiga, Grasslands, Savanna, Tropical rain forest, Temperate deciduous forest, Desert 19

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4 Biomes and their characteristics Tundra 1. Coldest of all biomes - Soil is frozen and only the top 0.5 mtrs melts during summers. The soil below that is permanently frozen and is called Perma-Frost. 2. Low biotic diversity Presence of very limited number of species (mosses, lichens) 3. Short season of growth 4. Low precipitation 5. Artic Tundra and alpine tundra 22

5 Biomes and their characteristics Taiga & coniferous forest 1. Word derived from Russian that means Primeval forest. 2. Also known as boreal forest or snow forest. Flora has leaves that are like needles. 3. Considered as a land of lakes and marshy lands. 4. Regarded as world s largest biome 23

6 Biomes and their characteristics Temperate deciduous forest 1. Located in the mid-latitude areas. 2. Have four distinct seasons - Leaves change color in autumn, fall off in the winter, and grow back in the spring; this adaptation allows plants to survive cold winters. 3. Vegetation consists of Broadleaf trees (oaks, maples, beeches). 4. Rainfall of 750mm to 1500 mm spread all through the year 24

7 Grasslands Temperate and tropical 25

8 Biomes and their characteristics Temperate grasslands 1. Open and continuous, fairly flat areas of grass. 2. Grasses can reach upto 2.1 m 3. Have cold winters and warm summers with some rain. 4. Low diversity of wildlife, but a high abundance of wildlife. 5. Very rich nutrients in soil ideal for cattle rearing. 6. Eg. - Prairies America, Pampas South America, Steppes Central Asia, Europe, Veldts South Africa 7. Agriculture has altered their spread 26

9 Biomes and their characteristics Tropical grasslands 1. Biomes dominated by grass and/or shrubs located in semi-arid to semihumid climate regions of subtropical and tropical latitudes 2. Savanna has scattered trees. Shrubland is dominated by woody or herbaceous shrubs. 3. Rainfall is between 500 and 1300 millimeters (20 to 50 inches) a year, and can be highly seasonal 4. Eg. Sahel region of Africa 27

10 Biomes and their characteristics Tropical rain forest 1. Rainforests that occur in areas of tropical rainforest climate in which there is no dry season all months have an average precipitation of at least 60 mm. 2. True rainforests are typically found between 10 degrees north and south of the equator 3. Rainfall is between 2000 mm to 3,000 mm causing poor soil quality due to excessive leaching 4. Tropical rainforests exhibit high levels of biodiversity. Around 40% to 75% of all biotic species are indigenous to the rainforests 5. Are called the "world's largest pharmacy", because over one quarter of natural medicines have been discovered within them 6. Tropical rainforests are among the most threatened ecosystems globally due to large-scale fragmentation as a result of human activity 7. Forest floor is relatively clear of vegetation because of the low sunlight penetration (2%). 8. The forest floor also contains decaying plant and animal matter, which disappears quickly, because the warm, humid conditions promote rapid decay 28

11 Tropical rain forest 29

12 Biomes and their characteristics Desert 1. A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. 2. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation (wearing away of rocks) 3. About one-third of the land surface of the world is arid or semi-arid 4. Temperatures exhibit daily extremes because the atmosphere contains little humidity to block the Sun's rays 5. Evaporation rates regularly exceed rainfall rates. Sometimes rain starts falling and evaporates before reaching the ground. Rainfall is lowest on the Atacama Desert of Chile, where it averages less than 1.5 cm. 6. Eg. Patagonia, Atcama, Gobi, Sahara, Thar, Arabian 30

13 Hot desert Cold desert 31

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15 Biomes and their characteristics Name of Biome Tundra Taiga and coniferous forest Temperate deciduous forest Tropical rain forest Savannah Grasslands Region Areas adjacent to poles and on mountains Northern Europe, America & Asia. Also known as Boreal or snow forest. Central and S. Europe, Eastern part of America, China, Australia Area around equator with heavy rainfall Tropical region - Africa, South America, Australia Temperate region dominated by grass. Parts of N & S Flora & Fauna Flora Litchen, mosses, sedges Fauna Reindeer, Arctic fox, polar bear, artic hare, Ptarmigan Flora Spruce, pine, fir (Coniferous evergreen) Fauna Siberian tiger, Wolves, Hawks Flora Beech, Oak, Maple, cherry Fauna Black & brown bear, Bald eagle, coyote, Duckbill platypus, 7% of area and 40% of species diversity of plants and animals. Contain many epiphytes (Plants that feed on other plants). Flora Grasses with scattered tree Fauna Grazers Buffalo, antelope, zebras. Carnivores Flora grass 33 Fauna Cattle, antelope, prairie dog, wolf

16 Aquatic zones/ecosystem They are classified on the basis of salinity, temperature, depth of sunlight penetration. Major aquatic ecosystems are Fresh water, Marine, Types Feature Fresh Water Lotic Moving water. Eg rivers, lentic - Still water. Egs. Ponds, Wetlands Soil is saturated for majority of the time Marine 3/4 th of earths surface is covered with this ecosystem containing 97% of water. Consists of dissolved salts. Classes of organisms found in marine ecosystems include brown algae, dinoflagellates (algae type), corals, cephalopods (eg squids), echinoderms (eg star fish), and sharks. Near-shore (neritic) zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps In the deep water, hydrothermal vents may occur where chemosynthetic sulphur bacteria form the base of food web. 34

17 Biotic interaction Type Species-1 Species-2 Example Mutualism* Benefit Benefit E.Coli in large intestine aids in production of Vitamin-K that inhibits growth of other bacteria, Fleas & Dogs Commensali sm Benefit No impact Cow dung provides food and shelter to dung beatles Amensalism Harmed No impact Shade of large tree stunting the growth of smaller tree Competition Harmed Harmed Any case where 2 or more species compete for limited food in the same area Predation & Parasitism Benefit Harmed Examples * - symbiotic relationship is a type of Mutualism 35