Introduction to Ecosystems Aims To understand what an ecosystem is. To learn about a small scale...
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Transcript of Introduction to Ecosystems Aims To understand what an ecosystem is. To learn about a small scale...
Introduction to EcosystemsAims
• To understand what an ecosystem is.
• To learn about a small scale ecosystem (a pond ecosystem)
DefinitionEcosystems 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).
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.
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.
The Climate of the World’s Major Ecosystems
Ecosystem Climate description
Temps
winter + summer
Rainfall winter + summer
TRF Hot and wet all year.
27–30oC. 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.
TemperateDeciduous 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.
Location of the global ecosystems
A Food Chain
A food chain is a line of linkages between producers and
consumers. It always begins with a plant.
A Freshwater Pond Food Chain
Heron
Fish
Great Diving Beetle
Midge Lava
Detritus (decaying leaves)
Con
sum
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sPro
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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.
A Freshwater Pond Food Web
Heron
Worms
Algae and microscopic plants
Mayfly
Great diving beetle
Stonefly
Fish
Kingfisher
Midge larva
Caddis
Dragonfly
Detritus
Blackfly
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).