the living world Flashcards
nutrient cycle
1) trees and organisms die and leaves fall
2) some nutrients are dissolved by precipitation and lost in runoff
3) as organisms decompose, they release nutrients
4) some nutrients are washed away (leaching) and some are added by weathered rock
5) nutrients are taken in from the soil by plants and the cycle repeats
characteristics of a savannah
- hot and dry in the summer
- short rainy season in the winter
- grasslands, bushes, stumps, large animals
- e.g. Africa and South America
characteristics of a desert
- hot and dry all year round, cold at night
- no plants mostly, few animals
- e.g. Sahara, Gobi
characteristics of a temperate deciduous forest
- warm in the summer, cold in the winter
- forest of deciduous trees
- e.g. Britain, Germany
characteristics of a Mediterranean scrub
- rainfall in summer
- dry cold winters
- scrubland and small bushes
- e.g. Greece, Turkey
characteristics of a coniferous scrub
- cold and dry all year long
- coniferous trees
- e.g. Russia and Canada
characteristics of a rainforest (in-depth)
- humid - wet and hot all year round, average temp. of 26 degrees celsius
- high rainfall leads to leaching, so the soil is infertile (however high sunlight and water supply)
- only covers 7 percent of land, but two thirds of plant species and half of all animal species
layers of a rainforest
- forest floor - dark, so few plants, mostly fallen leaves decomposing
- shrub layer - dense undergrowth of small plants (more found in clearings with sunlight)
- under canopy - trees up to 20m tall
- canopy - tall trees fighting to receive light
- emergents - trees taller than 50m, the tallest ones that stick out from the canopy
adaptations of plants in the rainforest
- bare lower tree trunks, so energy is not wasted by growing branches
- buttress roots - grow above ground to support tree
- tall trees - receive the most sunlight
- drip tips - shed rainfall to avoid fungus and large SA to absorb sunlight
- lianas (vines) - attach to trees to reach sun for support and share resources
adaptations of animals in the rainforest
- sloth - brown (camouflage), claws to grip onto branches, slow so that predators cannot catch them
- jaguar - brown spots, fast (apex predator)
- spider monkey - long limbs to swing on branches, tail as an extra limb
value of rainforests
- economic value - land use, logging, tourism, mining, medicines
- social value - scientific research, indigenous tribes
- environmental value - carbon sinks, biodiversity, flood defences
management of rainforests
- restrictions and laws protecting endangered species and deforestation
- debt reduction - can be spent on the preservation of rainforests
- ecotourism - no air travel
causes of deforestation
- building infrastructure
- land use
- logging
- mining
- hydropower (building dams and reservoirs)
- clearing space due to population growth
characteristics of polar environments (in-depth)
- permanent ice sheets
- soil permanently frozen (permafrost)
- ice prevents decomposition
- temperature below freezing
- little precipitation
characteristics of tundra environments (in-depth)
- below freezing except summer (3 - 12 degrees celsius)
- vulnerable to slightest change (fragile ecosystem)
- few plants and vegetation grow closely together, to conserve warmth
- some indigenous tribes
