Abiotic factors are the non-living, physical and chemical features of an ecosystem that affect the organisms living there. The main ones are:
• light intensity and day length
• temperature
• water availability and humidity
• oxygen and carbon dioxide availability
• wind and water currents
• edaphic (soil) factors, such as pH, mineral ions and drainage
• salinity and pH of water
Most of these have their own lesson later in this topic.Abiotic factors affect organisms in two main ways. They affect the rate of processes such as photosynthesis, respiration and enzyme activity, and so affect growth and reproduction. They also determine where species can live: each species can only survive within a certain range of each factor, called its range of tolerance.So abiotic factors affect both the distribution of a species and the size of its population. A factor that is in short supply and holds back the growth of a population is called a limiting factor. For example, in a dense woodland, light at ground level can limit the number of plants growing there.Abiotic factors often vary together. On a rocky shore, organisms near the top are exposed to air for longer at low tide, so they face higher temperatures and more drying out than those lower down. This produces zones of different species up the shore, each species living where it can tolerate the conditions.
• light intensity and day length
• temperature
• water availability and humidity
• oxygen and carbon dioxide availability
• wind and water currents
• edaphic (soil) factors, such as pH, mineral ions and drainage
• salinity and pH of water
Most of these have their own lesson later in this topic.Abiotic factors affect organisms in two main ways. They affect the rate of processes such as photosynthesis, respiration and enzyme activity, and so affect growth and reproduction. They also determine where species can live: each species can only survive within a certain range of each factor, called its range of tolerance.So abiotic factors affect both the distribution of a species and the size of its population. A factor that is in short supply and holds back the growth of a population is called a limiting factor. For example, in a dense woodland, light at ground level can limit the number of plants growing there.Abiotic factors often vary together. On a rocky shore, organisms near the top are exposed to air for longer at low tide, so they face higher temperatures and more drying out than those lower down. This produces zones of different species up the shore, each species living where it can tolerate the conditions.