Living organisms occupying a given habitat are exposed to conditions which are largely defined by the nature of the physical environment they inhabit.
T or F: Living organisms occupying a given habitat are exposed to conditions which are largely defined by the nature of the physical environment they inhabit. (TRUE)
Various abiotic factors that comprise the environment
the prime determiners of the abundance, distribution and over-all ecology of the biotic units of the ecosystem.
Biotic components include:
Producer
Consumers
Decomposers
Abiotic components
the complex of physical and chemical factors
Abiotic components
include:
climatic factors
edaphic factors
topographic factors
climatic factors
Light
Temperature
Humidity
Wind
Precipitation
edaphic factors
Soil nutrient
Acidity
Moisture
topographic factors
Aspect
Angle of slope
Altitude
A.G. Tansley (1935)
the biotic components (organisms) could not be separated from the abiotic (physical factors) with which they form one physical unit, the ecosystem.
Climate
result of the interplay of the following factors:
seasonal temperature
Humidity
Wind
Precipitation
Light conditions.
Weather
momentary conditions of the atmosphere.
Climate and weather
affect the distribution and activity of both terrestrial and aquatic organisms.
Laboratory thermometer - Field instrument used to measure temperature
Light meter - Field instrument used to measure light intensity
Slingshot psychrometer - Field instrument used to measure relative humidity
Wind meter and compass - Field instrument used to measure wind speed and direction
Barometer - Field instrument used to measure atmospheric pressure
Rain gauge - Field instrument used to measure precipitation
Aluminum pans - Field instrument used to measure rate of evaporation
Climatological factors
Temperature
Light Intensity
Relative Humidity
Wind Speed and Direction
Atmospheric Pressure
Precipitation
Rate of Evaporation
Ecological significance
Light - Photosynthesis; energy reservoir
Ecological significance
Temperature - regulate rate of growth, development, metabolism, and reproduction
Ecological significance
Humidity - influence water balance and respiration; cloud formation and precipitation
Ecological significance
Wind - role in seed, pollen, and spores dispersal; climate patterns, temp control, rate of evaporation
Ecological significance
Precipitation - primary source of freshwater; water availability; soil formation, and nutrient cycling
Ecological significance
Temperature - all biological processes
Climatic factors with ecological interactions (Wind and precipitation)
Wind for seed dispersal and Precipitation that can limit its distribution.
Low rainfall, strong winds can blow seeds before germination.
Heavy rainfall, saturate soils impeding germination
Climatic factors with ecological interactions (Humidity and temperature)
Affects the abundance and distribution of organisms by their ability to adapt to maintain water balance
Hot and humid envi, organisms lose excess water
Hot and arid envi, organisms and rapid water loss
Relative Humidity (RH)
vapor pressure of water in the air expressed as a percentage of the saturation pressure.
Relative humidity is the ratio of the actual vapor pressure of water in the air to the saturation pressure at that temperature, expressed as a percentage.
Relative Humidity
Higher temperature / warmer air means lower RH
Lower temp / cooler air means higher RH
factors affecting light intensity in a terrestrial habitat
sun angle
Seasonal changes,
cloud cover,
latitude,
topography, and
vegetation density
factors affecting light intensity in a aquatic habitat
depth due to water absorption and scattering
turbidity
angle of sunlight
ice cover
Temperature and capacity to hold water vapor
Warmer air / high temp has a higher capacity to hold water vapor, resulting in lower RH if the water vapor remains constant
Cooler air / low temp has decreased water vapor capacity, resulting in higher RH for the same water vapor content
Relative Humidity and Water Loss
In low RH envi, organisms lose water faster because of higher water vapor capacity creating diffueion (water from organisms to dry air regions)
In high HR envi, organisms have slower water loss due to lower water vapor capacity
Precipitation rate and atmospheric pressure
Lower atm pressure, increased precipitation because of rising air that cools and condenses
Higher atm pressure, reduced precipitation because of clear skies
Wind velocity and animal activity & plant transpiration
High wind speeds often lead to reduced activity levels in small animals due to increased energy expenditure required for movement against strong winds.
High wind speed increases plant transpiration through the removal of humid air surrounding leaves, resulting in a vapor pressure gradient that drives water vapor diffusion into drier air.
Soil
the weathered superficial layer of the earth’s crust comprised of minerals and organic matter and is capable of supporting plant growth (Smith, 1980).
Aside from the plants a great number of micro and macroinhabitants dwell in the soil medium. The burgeoning and survival of all of these organisms, therefore, will be dependent on factors related to the soil itself.