environmental factors
TRANSCRIPT
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Environmental Factors
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Environmental Factors
• Edaphic: These refer to the soil.
• Climatic: These are the average weather conditions
that affect the community in an ecosystem.
• Biotic: These are living factors.
• Fire: It is chemical chain reaction which takes place
with the evolution of heat and light.
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Edaphic factors include
• Soil type:
ü Sandy soil
ü Clay soil
ü Loamy soil
• Soil pH:
• Available (soil) water:
ü (Adhesion water, Cohesion water, Gravitational water)
ü Water makes up 25% of a soil
• Air and Mineral content:
ü Air is found in spaces (pores) between soil particles.
ü Air supplies oxygen and nitrogen that help plants to grow.
ü Air makes up 25% of a soil.
• Humus
ü The remains of dead plants and animals.
ü Dead plants are broken down into humus by micro-organisms (earthworms, fungi).
ü Humus darkens the soil and increases fertility and is found near the surface.
ü Organic matter makes up about 5% of a soil usually.
• Soil texture and Structure
ü Roughness
ü Gaps
ü Amount of air
ü Water passing through
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Climatic Factors (Long-term weather)
• Temperature:
ü Is an important factor in the distribution of organisms because of its effects on
biological processes?
ü Global Warming: increase in Earth's average surface temperature only.
• Rainfall:
ü Rainfall is the most important climatic factor in determining areas at risk of land
degradation and potential desertification.
ü Rainfall plays a vital role in the development and distribution of plant life, but the
variability and extremes of rainfall can lead to soil erosion and land degradation.
• Day length:
ü Day length changes over time.
• Light intensity:
ü Can affect photosynthesis in ecosystems
ü Is also important to the development and behavior of organisms sensitive to the
photoperiod.
ü Plays a major part in determining the Earth’s climate patterns.
• Wind:
ü In the arid and semi-arid zones of the world, 24% of the cultivated land and 41%
of the pasture land affected by moderate to severe land degradation from wind
erosion.
ü Sand and dust storms are hazardous weather and cause major agricultural and
environmental problems in many parts of the world.
ü Sand and dust storms strong winds to bury crops.
ü Can change the morphology of plants.
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Humidity:
This chart shows how relative humidity changes with temperature
Relative humidity is affected by temperature
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Total annual production of dust world-wide by deflation of soils and
sediments was estimated to be 61 to 366 million tons.
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Biotic Factors (Living)
• Food:
ü Many animals are directly dependent on plants for food.
• Competition:
ü Plants struggle for light will influence root development and the
competition for water.
• Predation:
ü The dominant plants will grow tallest and modify the light conditions
for the rest of the community.
• Parasitism:
ü Man modifies of ecosystems by fire, hunting and agriculture…
• Pollination:
ü Man is by far the most important biotic factor
• Seed Dispersal:
ü Many plants rely on animals for pollination and seed dispersal.
• Human activity:
ü Industrialization and the intensification of agriculture, man has
obliterated large areas of natural systems and caused pollution of both
terrestrial and aquatic habitats.
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Biotic Factors (Living)
iotic Factors (Living)
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Fire
Impact of fire on the natural environment
• Impact on Plant
ü Regeneration
ü Bane
• Impact on Soils:
ü Can sterilise living tissue in soils.
ü Ash-bed effect can increase fertility of soil.
ü Chemical structure of the soil can be changed.
ü Changes in soil’s permeability (its ability to absorb water).
ü Removal of vegetation.
ü Often results in erosion.
• Impact on Water :
ü Fires can affect the quality and amounts of water in creeks, rivers and heavy rain
soon after the fire.
• Impact on Animals:
ü Many animals are killed during fires.
ü Find new sources of food.
• Impact on Air:
ü Noxious gases: These include carbon dioxide (CO2), sulphur dioxide (SO2) and
nitrogen oxides (NOx).
ü Particulates: These are tiny particles suspended in air (e.g. smoke) and which are
usually produced by the combustion of fossil fuels.
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Impact of fire on Plant
Impact of fire on Animals
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