7 - biomes Flashcards
(27 cards)
define a biome
- a large-scale, global ecosystem with distinct vegetation
- the 7 biomes are : tropical forest / temperate forest / boreal forest / tropical grassland / temperate grassland / desert / tundra
- (pg. 87 for location diagram)
describe the tropical forest’s climate
- same all year round
- very hot because near to the sun (equator)
- very high rainfall, around 2000mm/y
describe the tropical forest’s characteristics
- plants grow quickly and are adapted to take in maximum light
- dense vegetation, species and habitats like jaguars, anacondas, gorillas
- everything dead decomposes quickly, so there is a constant supply of nutrients in the soil that are cycled quickly
describe the temperate forest’s climate
- four distinct seasons, with warm summers and cool winters
- very high rainfall (up to 1500mm/y)
- shorter days in winter, longer in summer
describe the temperate forest’s characteristics
- decent number of plant species / forests have broad-leaved trees, shrubs and undergrowth
- habitats of mammals, birds and insects
- decent speed of decomposition, so soils are relatively thick and nutrient-rich
describe the boreal forest’s climate (aka Taiga)
- short cool summers, long cold winters (below 20c)
- low precipitation, which often falls as snow
- daylight in summer months, little to none in winter
describe the boreal forest’s characteristics (aka Taiga)
- evergreen and coniferous trees
- relatively few animal species because of less food availability and cold climate
- plants decompose slowly, so thin, nutrient-poor soil. ground is often mostly frozen
describe the tropical grassland’s climate
- low rainfall
- distinct wet and dry seasons
- highest temp. before wet season (35c), lowest temp after it (15c)
describe the tropical grassland’s characteristics
- grass, scrubs and small plants
- insects, lions, elephants, giraffes, etc
- thin, nutrient-rich soil in dry seasons, but washed out in wet seasons
describe the temperate grassland’s climate
- very hot summers, very cold winters
- low rainfall
- varied light because far from equator
describe the temperate grassland’s characteristics
- grass and small plants
- fewer animal species - mammals and rodents
- high temp in summer means fast decomposition so relatively thick and nutrient-rich soil
describe the desert’s climate
- very low rainfall, maybe once every 2/3 years
- HOT deserts are very hot in day, cold at night
- HOT deserts get lots of sunlight because of little cloud cover
describe the desert’s characteristics
- sparse plant growth, maybe cacti
- few animal species, but those are adapted to harsh climates (e.g lizards, snakes, scorpions)
- little decomposition anyway, but slow so soils are thin and nutrient-poor
describe the tundra’s climate
- low in summer and VERY low in winter (-30c)
- low precipitation, most of it falls as snow
- continuous daylight in summer, and little to no daylight in winter, due to high latitudes
describe the tundra’s characteristics
- barely any plants or trees
- few species - some arctic foxes/hare and lots of birds that migrate south for the winter
- thin, nutrient-poor soils, and a layer of permafrost below the soil surface
what factors is biome distribution affected by?
- altitude (colder climate, so limits species and matter)
- rock type (weathering/permeability/nutrient differs)
- soil type ( acidity/drainage/nutrient differs)
- drainage (if drainage is poor, soil gets waterlogged and conditions become very wet)
examples of biotic/abiotic components
- biotic: flora & fauna
- abiotic: soil, water, rock, atmosphere
how does the biosphere provide resources for humans?
- food
- medicine (lots of plants have medicinal properties)
- building materials (pine/sap/straw)
- fuel (wood/grass/animal fat burnt as fuel by the indigenous)
how do humans exploit the biosphere through energy demand?
increasing demand for energy means:
- forests are cut down to clear land for cash crops
- trf is often flooded by the building of hydroelectric dams
- drilling for oil in tundra melts the natural permafrost
how do humans exploit the biosphere through water demand?
increasing demand for water means water resources (lakes/rivers/aquifers) being over-exploited, so plants and animals often no longer have enough water to survive
how do humans exploit the biosphere through mineral demand?
increasing demand for minerals such as gold/iron means increased mining in tropical forests which are responsible for lots of deforestation and toxic chemicals being washed into streams and rivers, killing wildlife
how and why does the biosphere help regulate the atmosphere?
- plants take in co2 and give out oxygen in photosynthesis
- decreases global warming and neutralises acidic soils, affecting the organisms living there
how does the biosphere keep soil healthy?
- plant roots and certain animals spread nutrients through the soil, helping maintain soil structure and fertility
- roots of vegetation, hold the soil together protecting it from eroding
- vegetation intercepts rainfall before reaching the ground to prevent leaching (where nutrients in the soil) are washed away
how does the biosphere regulate the water cycle?
- water is taken up by plants, so less reaches rivers, preventing flooding and soil erosion
- plants release water slowly into the atmosphere, reducing the risk of droughts in drier areas (eg trf)
