G1B The Living World Cheat Sheet (DRAFT) by genius_elffo

· the organisms in ecosystems can be classed as producers, consumers, or decomp­osers

When dead material is decomp­osed, nutrients are released into the soil. The nutrients are then taken up from the soil by plants.
The plants may be eaten by consumers. When the plants or consumers die, the nutrients are returned to the soil.

Components of an ecosystem depend on others, e.g. consumers depend on producers for a source of food or habitat.

->

hot dry summer > reduced plant growth > fewer berries for birds in the winter > number of sparrows & thrushes fall >
fewer birds for sparro­whawks to hunt so numbers fall

producers > primary consumers > secondary consumers > tertiary consumers

· as you move up the food web, energy is lost at each stage, which means less consumers can be supported
· each consumer in a food chain 'wastes' / 'uses' nearly all energy taken in
· around 90% of energy at each level is lost through life processes

Charac­ter­istics of Epping Forest Food Web

· large number of native tree species, e.g. oak, elm, ash & beech
· lower shrub layer of holly & hazel at 5m, overlying grassesm bracken, fern & flowering plants -> 177 species of moss & lichen
  -> great diversity of producer species
· many insect, mammal & bird consumer species -> 9 amphibian & reptile species and 38 bird species
· 700 species of fungi -> important decomp­osers

Explan­ation of Charac­ter­istics of Epping Forest Nutrient Cycle

· the biomass store is large due to the great height of trees & dense underg­rowth
· the soil store is large due to plenty of humus
· high flow rates between litter, soil & biomass stores reflect the viogorous cycle of new growth that takes place each year
· the forests also loses a lot of nutrients each year, via leaching, during episodes of heavy rainfall

How does Hadley cells influence the distri­bution of global ecosys­tems?

· the circul­ation of air in Hadley cells influences climate as well
· places located on the equator tend to be wetter as air rises and condenses to form clouds ;
  - tropical rainfo­rests usually found on the equator · places located on the tropics tend to be drier as air sinks there ;
  - deserts usually found on the tropics

· the soil isn't very fertile as heavy rain washes nutrients away
· there are only nutrients at surface due to decayed leaf fall, however this layer is very thin due to fast decay
  in warm, moist conditions

· rainforest ecosystems contain more animal species than any other
· e.g. gorillas, jaguars, anacondas, tree frogs & sloths

· no roots to bind soil -> soil erosion -> landslides & flooding
· no tree canopy to intercept rainfall & no tree roots to absorb water -> more nutrients washed away ->
  reduces soil fertility
· no trees to remove CO2 & burning vegetation releases CO2 -> more CO2 in atmosphere
  ->adds to greenhouse effect -> worsen climate change

Sustai­nable Management

selective logging



replanting



ecotourism

· only some older trees are felled ; most trees are left standing
· this means the overall structure of forest is kept, so that the forest will be able to regenerate to be used in future
· helicopter logging is used in Sarawak, Malaysia, removing felled trees with helico­pters instead of trucks

· new trees are planted to replace the ones cut down
· same types of tree planted to maintain variety
· there are laws to make logging companies to replant trees

· ecotourism minimises damage to enviro­nment & benefits locals
· income in ecotourism for locals (e.g. guides, providing accomm­odation & transport) -> less employment in logging
· country's economy reliant on ecotourism -> more incentive & raise awareness for conser­vation
· e.g. ecotourism = largest source of income in Costa Rica (21%)