Populations, sustainability and ecosystems - 6 Flashcards
What is an ecosystem
All the biotic and abiotic components in a specific area and their interactions
What are biotic factors
Living factors
What are abiotic factors
Non-living factors
Name 4 biotic factors
Plants
Animals
fungi
bacteria
Name 4 abiotic factors
Light
Temperature
pH
Water
What are the components of an ecosystem
Habitat
Population
Community
What is a habitat
A place where an organism or population live
What is a population
A group of organisms of the same species which live in the same place
What is a community
All of the populations of different species who live in the same place
What is a niche
An organisms specific role in the ecosystem
What is biomass
The total weight of living matter in a certain area, transferred up trophic levels through consumption
How can biomass be measured
Can be measured in terms of mass of carbon, or dry mass of tissue
Give the equation for efficiency of biomass transfer
Efficiency = biomass transferred/biomass intake * 100
How can human activities affect biomass transfer
Light, water, temperature maximised
Increased nutrients in soil
Pests and weeds removed
Growth rates boosted
Outline the roles of microorganisms in the nitrogen cycle
Nitrogen-fixing bacteria convert gaseous nitrogen into ammonia
Nitrifying bacteria convert ammonium compounds into nitrates
Nitrobacter then convert nitrites into nitrates
Give two examples of nitrogen-fixing bacteria
Rhizobium in roots
Azotobacter in soil
Give an example of a nitrifying bacteria
Nitrosomonas
Outline the role of organisms in the carbon cycle
Respiration of plants and animals add carbon dioxide into the atmosphere
Photosynthesis of plants removes carbon dioxide from the atmosphere
Decomposers decay plant and animal material into carbon dioxide
Define primary succession
Where an area previously devoid of life is colonised by a community of organisms
Explain the process of primary succession
Pioneer species, able to survive harsh conditions, colonise the area
They die, decompose and add nutrients to the ground
Over time, this allows more complex organisms to survive
What is a climax community
The final stage of succession, where the ecosystem is balanced and stable
How is a climax community reached
When the soil is rich enough to support large trees or shrubs and the environment is no loner changing
What is deflected succession
Where succession is interrupted, usually be human interference
Define carrying capacity
The maximum population size that a habitat can support, defined by the presence of limiting factors
