The distribution, diversity and numbers of plants and animals in
ecosystems are determined by biotic and abiotic factors
A Local Ecosystem
Abiotic Characteristics
Abiotic factors include non-living
components of the environment
●
Temperature
●Rainfall
●Wind
●Light intensity
●Humidity
●pH
●salinity
●
Abiotic factors of aquatic and
terrestrial environments
Abiotic Characteristic
Aquatic environment
Terrestrial environment
Availability of oxygen
(oxygen is needed for
aerobic respiration)
Oxygen is less available in Oxygen is more available
water than in air
making up approximately
20% of atmosphere
Temperature variation
Depends on depth of
water and latitude. Large
bodies of water have
relatively small variation in
temperature. Small bodies
of water heat up and cool
more quickly
Pressure variation
Water pressure increases Air pressure decreases
with depth of water
with altitude
Light penetration
Depends on depth
Depends on latitude and
altitude. Large variations in
temperature can occur –
greater than aquatic
environments
Is easily available. Can be
limited by other vegetation
or topographic features
Factors affecting distrbution and
abundance
Availability of food source
●Abundance and range of predators
●Competitors for food sources or resources
●Climate conditions (temperature + rainfall)
●
Photosynthesis and
Respiration
Photosynthesis is the chemical process
used by chlorophyll-containing cells to
convert inorganic raw materials into organic
compounds using light energy
●Respiration is a series of chemical reactions
which releases energy from complex
carbohydrates
●
Glucose + oxygen
carbon dioxide + water
●This process does not occur in one step. There are about
50 different stages, each catalysed by a different enzyme.
●
Roles of photosynthesis and
respiration in ecosystems
Photosynthesis
●
Formation of glucose enables the conversion of...