6.5 ECOSYSTEMS Flashcards
Define succession
- The progressive change in a community of organisms over time
Define pioneer species
- Species that begin the process of succession by colonising an area as the first living organism there
Define climax community
- The final stable community that exists after succession has occurred
Define deflected succession
- When succession is interfered with or stopped preventing a stable climax community
Define primary succession
- Succession starting from a previously uninhabited environment
Define secondary succession
- Succession restarting from a disrupted environment
State three factors that explain why secondary succession is easier/faster than primary succession
- Left over seeds in soil
- Left over organisms in soil
- Left over bacteria in soil
State three reasons why deflective succession happens
- human activity (agriculture/urbanisation/pollution)
- abiotic factors (wave action/fires/shape of landscape)
- biotic factors (trampling/animal eating)
State three changes simple organisms undergo before and after succession to become complex organisms
- From autotrophs to auto & heterotrophs
- From minimal nutrition requirements to complex nutrition requirements
- From extremophiles to being sensitive to environmental change
State four changed to the community after succession
- Increase in interdependence
- Increase in productivity
- Increase in biodiversity
- Increase in abiotic/environmental favourability
Describe the term ecosystem
- A community and the abiotic components of an environment
- Range in size
- Dynamic
State what biotic and abiotic factors influence in an ecosystem
- the carrying capacity of a population
- the distribution of populations
Describe five factors that are abiotic
1) Light (affects photosynthetic organisms)
2) Temperature (affects metabolic rates)
3) pH (affects enzymes)
4) Water availability (affects photosynthesis and temp fluctuations)
5) Topography of landscape (affects light exposure)
6) Oxygen concentration (affects respiration
Describe three factors that are biotic
1) Intra/Interspecific competition
2) Pathogenic disease
3) Predator-prey interactions
Define biotic
- Living
Define abiotic
- Non-living
Describe the three types of dynamic changes in an ecosystem
1) Cyclic changes (seasonal temperature changes/predator-prey cycles)
2) Directional changes (erosion/sand deposit in lakes)
3) One-off changes (natural disasters)
Define autotrophs
- Organism that makes its own food
Define heterotrophs
- Organisms that eat other organisms for food
State three reasons why there is not 100% efficiency of energy transfer in food chains
- Respiration
- Organism isn’t fully eaten
- Not all of the organism is digested so is faeces
State the efficiency formula for biomass transfer
List the types of organisms and their relative energy content in a basic food chain
Producer (1000kJ) → Primary consumer (100kJ) → Secondary consumer (20kJ) → Tertiary consumer (5kJ)
State why the first energy transfer in a food chain is relatively lower than thesecond energy transfer
- Its harder to digest plant tissue
- Its easier to digest meat
Define gross primary productivity (GPP)
- The rate of conversion of light energy to chemical energy in producers during photosynthesis
Define net primary productivity (NPP)
- The rate of conversion of light energy to chemical energy in producers during photosynthesis, MINUS the chemical energy used in respiration
Define gross secondary productivity (GSP)
- The rate of chemical energy transfer to consumer from previous trophic level
Define net secondary productivity (NSP)
- The rate of chemical energy transfer to consumer from previous trophic level, MINUS the chemical energy used in respiration
State what the net primary/secondary productivity tells us
- This is the amount of energy actually stored as biomass
State five ways increasing primary productivity
1) Artificial lighting
2) Glasshouse
3) Selective breeding
4) Genetic modification for higher yeilds/pest resistance
5) Fertilisers
State six ways increasing secondary productivity
1) Restrict movement
2) Shelter from predators
3) Insulation
4) High nutrient diet
5) Selective breeding
Draw the nitrogen cycle
Define nitrogen fixation and which bacteria does this
- Rhizobium bacteria and Azotobacter bacteria
Define ammonification
Define nitrification and which bacteria does this
1) Nitrosomonas bacteria
2) Nitrobacter bacteria
Define denitrification and which bacteria does this
- Denitrifying bacteria
Draw the carbon cycle
Describe the process of primary succession on bare rock
1) Arrival of seads/spores on bare rock as a pioneer community
2) Pioneer community have specific adaptations (e.g nitorgen fixation)
3) Intermediate community forms via moss/herbs species as there is
4)
Describe the process of secondary succession on sand dunes