Abiotic Factors

Abiotic factors are any non-living factors that affect an organism or shape its environment. These include:

  • Temperature
  • Moisture levels
  • Light intensity
  • Soil pH and mineral content
  • Wind intensity and direction
  • Carbon dioxide levels
  • Oxygen levels of the water

Changes in abiotic factors can affect the number of organisms in a population and the rate of growth.

Effects of Abiotic Factors

Temperature

Temperature affects the rate of photosynthesis. As the temperature rises, the enzymes involved can work faster. Due to this, there is an increase in the rate of plant growth.

An increase in temperature also means that animals are able to spend less energy trying to keep warm.

Moisture levels

Animals and plants both need a sufficient amount of water to survive.

Light intensity

Plants need light for photosynthesis and the rate of photosynthesis affects the rate of plant growth.

  • Increased light intensity leads to an increased rate of photosynthesis. As a result, there is an increase in the rate of plant growth.
  • Reduced light intensity leads to a reduced rate of photosynthesis. As a result, there is a reduction in the rate of plant growth.

In areas of slow plant growth, there will be fewer plants for organisms to eat.

Soil pH and mineral content

The pH of soil affects the rate of decay, which in turn affects how fast mineral ions return to soil for uptake by plants.

Different species of plants thrive under varying nutrient concentrations.

  • For plant species that thrive in low pH (acidic) soil – The rate of decay is slow, leading to a slower return of mineral ions to the soil. Therefore, the rate of plant development is relatively slow.
  • For plant species that thrive in high pH (alkaline) soil – The rate of decay is faster, leading to a quicker return of mineral ions to the soil. Therefore, the rate of plant development is relatively fast.

Wind intensity and direction

Wind affects the rate of transpiration in plants.

Transpiration plays a role in the rate of photosynthesis by transporting water and mineral ions from the roots to the leaves.

  • Lower wind speed– Results in a lower rate of transpiration. So, less water and mineral ions are transported from the roots to the leaves.
  • Higher wind speed– Results in a higher rate of transpiration. So, more water and mineral ions are transported from the roots to the leaves.

Carbon dioxide levels

The carbon dioxide levels affect the rate of photosynthesis in plants.  

  • Lower level of CO2 – Slower rate of photosynthesis.
  • Higher level of CO2 – Faster rate of photosynthesis.

Oxygen levels in aquatic environments

Oxygen concentrations in water are typically lower than in the air. Aquatic animals have adapted to survive in water, but only some can only survive in water with low concentrations of oxygen.

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