The Living

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The Living World
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Ecosystems
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Introduction to Ecosystems
Aims

• To understand what an ecosystem is.

• To learn about a small scale ecosystem (a pond
• ecosystem)

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Definition Ecosystems are the interaction between
the living and the non-living environment.
Ecosystems are the interaction between plants,
animals or people and things such as local relief
(shape of the land), climate, soils and
vegetation (plants and trees).
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Ecosystems can be identified at different scales.
A local ecosystem may be as small as a pond or a
hedge. Larger ecosystems include lakes or
woodlands. Ecosystems found on a global scale
(also called biomes) include tropical rainforests
and deciduous woodlands.
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• Global ecosystems are known as biomes. The
  dominant type of vegetation cover usually defines
  a biome.
• There are many different ecosystems in the world.
  We are going to study 3
• Temperate Deciduous Woodlands
• Tropical Rainforests
• Hot deserts
• The main factor that influences the distribution
  (where they are found) of each ecosystem is
  climate.
• Each ecosystem has a different soil depending on
  the climate and vegetation.

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The Climate of the Worlds Major Ecosystems
Ecosystem Climate description Temps winter summer Rainfall winter summer
TRF Hot and wet all year. 2730oC. Wet all year. TAP 2000-3000mm.
Hot Desert Very hot most of the year. Above 30oC. TAP below 250mm.
Mediterranean Hot summers. Mild/warm winters. Summers about 25oC. Winters about 10oC. Dry in summer. Wet in winter. TAP 750mm.
Temperate Deciduous Woodland Warm summers. Mild/cold winters. Summer about 18oC. Winter about 5oC. Precipitation all year. TAP 1000mm.
Coniferous Woodland Warm summers. Very cold winters. Summer 16-20oC. Winter below freezing. Mainly in summer. TAP low (below 500mm).
Savanna Grasslands Hot all year. 25-35oC. Variable rainfall totals but always a drought period. TAP 500-1000mm.
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Location of the global ecosystems
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A Food Chain
A food chain is a line of linkages between
producers and consumers. It always begins with a
plant.
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A Freshwater Pond Food Chain
Heron
Fish
Consumers
Great Diving Beetle
Midge Lava
Detritus (decaying leaves)
Producer
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A Food Web
A food web is more complex than a food chain. It
is a diagram that shows the linkages between
producers and consumers in an ecosystem.
Food chains and food webs both show the transfer
of energy through an ecosystem.
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A Freshwater Pond Food Web
Kingfisher
Heron
Fish
Great diving beetle
Caddis
Dragonfly
Stonefly
Worms
Mayfly
Midge larva
Blackfly
Algae and microscopic plants
Detritus
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The Impact of Change on the Freshwater Pond
Ecosystem The number and the types of species in
an ecosystem can change over time and these
changes often have impacts in other parts of the
ecosystem. Changes can be caused by natural or
human factors.

• Natural Factors
• Changes in the environment may occur through
  floods, fires and drought.

• Human Factors
• Changes in drainage basins
• Depletion of fish stocks
• Deforestation
• Increased human use for timber and land for
  settlements and farmland (e.g. in the Tropical
  Rainforests).