Ecosystems and their functioning
Ecosystems at Risk
Ecosystems and their functioning
What is an ecosystem?
Ecology – the science that examines the interactions between organisms and their living (biotic) and non-living (abiotic) environment.
Groups of organisms and their biophysical environment interact and exchange matter and energy.
Ecosystem – the dynamic complex of plant, animal and micro-organism communities and their non-living environment as a functional unit.
Ecosystems are dynamic; constantly changing and adapting.
Ecosystems are systems through which incoming solar energy is captured (photosynthesis) and channelled through a hierarchy of life forms.
Each ecosystem has its own characteristic plant and animal community.
The quest for food is the central organising principle with in ecosystems.
Important feature is the set of processes by which nutrients are retained and recycled.
Living things recycle nutrients obtained from air, soil, water and other organisms, using solar energy to build and maintain themselves.
Variations in Ecosystems
Components of any ecosystem can vary naturally or due to human intervention.
Variations will affect other components and processes which may be magnified.
There have been substantial fluctuations in environmental conditions over the past 18,000 years.
E.g. Climate change and rising sea level.
Classifying Ecosystems
Classified according to their dominant features.
Land based ecosystems = terrestrial ecosystems or biomes. (Forests, deserts, grasslands).
Differences between terrestrial ecosystems primarily arise from variations in average temperature and precipitation.
Water based ecosystems = aquatic ecosystems. (Ponds, lakes, rivers, oceans, wetlands, coral reefs).
Differences between aquatic ecosystems primarily arise from variations in the amount of nutrients dissolved, salinity, depth of sunlight penetration (turbidity) and average temperature.
Ecosystems rarely have distinct boundaries.
Zone of transition = ecotone.
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Ecosystems and their functioning
What is an ecosystem?
Ecology – the science that examines the interactions between organisms and their living (biotic) and non-living (abiotic) environment.
Groups of organisms and their biophysical environment interact and exchange matter and energy.
Ecosystem – the dynamic complex of plant, animal and micro-organism communities and their non-living environment as a functional unit.
Ecosystems are dynamic; constantly changing and adapting.
Ecosystems are systems through which incoming solar energy is captured (photosynthesis) and channelled through a hierarchy of life forms.
Each ecosystem has its own characteristic plant and animal community.
The quest for food is the central organising principle with in ecosystems.
Important feature is the set of processes by which nutrients are retained and recycled.
Living things recycle nutrients obtained from air, soil, water and other organisms, using solar energy to build and maintain themselves.
Variations in Ecosystems
Components of any ecosystem can vary naturally or due to human intervention.
Variations will affect other components and processes which may be magnified.
There have been substantial fluctuations in environmental conditions over the past 18,000 years.
E.g. Climate change and rising sea level.
Classifying Ecosystems
Classified according to their dominant features.
Land based ecosystems = terrestrial ecosystems or biomes. (Forests, deserts, grasslands).
Differences between terrestrial ecosystems primarily arise from variations in average temperature and precipitation.
Water based ecosystems = aquatic ecosystems. (Ponds, lakes, rivers, oceans, wetlands, coral reefs).
Differences between aquatic ecosystems primarily arise from variations in the amount of nutrients dissolved, salinity, depth of sunlight penetration (turbidity) and average temperature.
Ecosystems rarely have distinct boundaries.
Zone of transition = ecotone.
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