Abiotic Factors

Abiotic factors: the non-living factor which affects the distribution of an organisms.
Temperature: extreme temperatures affect the enzymes in the organism and therefore it's overall metabolism (chemical reactions).
If the temperature is too cold, the enzymes will not have enough kinetic energy to catalyse the reaction quickly enough.
Light intensity: light is needed for photosynthesis, so the more light available the greater the rate of photosynthesis. As plants photosynthesise more, the more energy they will have for seed/spore production.
Water availability and humidity: water acts as a solvent in cells and is involved in many reactions directly. It acts as a hydrostatic skeleton in many species. Water loss by evaporation.
pH: pH can affect the extra cellular enzymes and surface proteins. pH may also affect the availability of mineral salts in the soil and therefore can affect growth of plants.
The more extreme these factors are, the fewer the number of species that can tolerate them and the smaller the population sizes will be.