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