THE ECOSYSTEM

What is Ecosystem? The community and the abiotic or non-living environment together make up an ecosystem or ecological system.

In this system energy flow is clearly defined from producers to consumers and nutrient cycling takes place in paths that links all the organisms and the non-living environment.

Biomass

This is the mass of all the organisms in a given area. Ideally, it is the dry mass that should be compared.

Carrying capacity:

This is the maximum sustainable density in a given area e.g. the number of herbivores a given area can support without overgrazing.

Factors in an Ecosystem

Abiotic factors (environmental factors)

Temperature

1. Is the hotness or coldness of an area or habitat.
2. It directly affects the distribution and productivity (yield) of populations and communities.
3. Most organisms are found in areas where temperature is moderate.
4. However, certain plants and animals have adaptations that enable them to live in areas where temperatures are in the extremes such as the hot deserts and the cold polar regions.
5. Temperatures not only influence distribution of organisms but also determine the activities of animals.
6. High temperature usually accelerates the rates of photosynthesis, transpiration, evaporation and the decomposition and recycling of organic matter in the ecosystem.

Light

1. Light is required by green plants for photosynthesis.
2. Light intensity, duration and quality affect organisms in one way or another.

Atmospheric Pressure

1. The force per unit area of atmospheric air that is exerted on organisms at different altitudes.
2. Growth of plants and activity of animals is affected by atmospheric pressure e.g., rate of transpiration in plants and breathing in animals.

Salinity

1. This is the salt content of soil or water.
2. Animals and plants living in saline conditions have special adaptations.

Humidity

1. This describes the amount of moisture (water vapour) in the air.
2. Humidity affects the rate of transpiration in plants and evaporation in animals.

pH

1. Is the measure of acidity or alkalinity of soil solution or water.
2. pH is very important to organisms living in water and soil.
3. Most prefer a neutral pH.

Wind

1. Is moving air currents and it influences the dispersion of certain plants by effecting the dispersal of spores, seeds and fruits.
2. Air currents also modify the temperature and humidity of the surroundings. Topography:
3. These are surface features of a place.
4. The topographical factors considered include altitudes, gradient (slope), depressions and hills.
5. All these characteristics affect the distribution of organisms in an area
6. g., the leeward and windward sides of a hill.

Biotic factors

These are the living components in an ecosystem,

1. competition
2. predation,
3. symbiosis,
4. parasitism,
5. human activities.