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106 Components of an Ecosystem Key Idea: An ecosystem is made up of all the living (biotic) and non-living (abiotic) factors within a
PR E V ON IEW LY
particular environment.
What is the biosphere?
ffThe biosphere is a narrow belt around the Earth containing all the Earth’s living organisms. It extends from
the bottom of the oceans to the upper atmosphere. Broad scale life-zones or biomes within the biosphere are characterised according to the main vegetation type. Within these biomes, ecosystems form natural units made up of the non-living, physical environment (the atmosphere, water, and soil) and the community.
The ecosystem
The concept of the ecosystem was developed to describe the way groups of organisms are predictably found together in their physical environment. A community comprises all the organisms within an ecosystem. The structure and function of a community is determined by the physical (abiotic) and biotic factors, which determine species distribution and survival.
Physical environment abiotic factors:
Atmosphere
• • • •
Wind speed and direction Light intensity and quality Precipitation and humidity Air temperature
Community: biotic factors
Soil
Nutrient availability Soil moisture and pH Composition Temperature
• • • •
Dissolved nutrients pH and salinity Dissolved oxygen Temperature
1. Distinguish between biotic and abiotic factors:
Interact in the community as: Competitors, parasites, pathogens, symbionts, predators, herbivores
No Cla t fo ssr r o Us om e
123Rf Tomas Sobek
• • • •
• Producers • Consumers • Detritivores • Decomposers
Water
2. Use one or more of the following terms to describe each of the features of a beech ecosystem listed below: Terms: population, community, ecosystem, physical factor.
(a) All the beech trees present:
(c) All the organisms present:
(b) The entire forest:
(d) The humidity:
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