Abiotic selection factors

Selection factors

Selection factors are those environmental conditions / factors that affect the individuals and thus their fitness. A distinction is made between abiotic (inanimate) and biotic (living) selection factors.

The selection factors are crucial to the direction of evolution.

Abiotic environmental factors: all selection factors that emanate from the inanimate environment. These can be:

 Temperature (Example 1: Individuals of one species are usually smaller in warmer areas, as their relatives in colder latitudes -> Galapagos penguin inhabits the Galapagos Islands and is about 50cm tall, the Antarctic emperor penguin, however, comes to about 110cm also: Bergmann's rule)

(Example 2: The relative length or size of extremities is greater in animal species in warm areas than in related animals in cold climates -> Comparison of the ears of desert fox (Fennek) and polar foxes.Reasoning see also: Allensche rule)

 Moisture (example: Exceptional environmental conditions, such as the enormous and prolonged aridity in desert areas, lead to plants with very low water consumption, up to the formation of stem succulents that can store water)

 Wind (Example: The wings of the Kerguelenfliege (inhabiting the Kerguelen island groups in the Indian Ocean) have regressed during the course of the evolution.Flies with trained pair of wings were often blown out by storms on the open sea.Therefore, there may be an evolutionary advantage on windy islands to have stunted wings.

 Nutrients (Example: Carnivorous plants are able to settle on nitrogen-poor soils as they can balance the missing minerals through their prey animals)

 Poisons (Example: Selection pressure when antibiotics are given to support resistant bacterial strains.)

Summary

Abiotic (ancient Greek a- = un, bios = life -> inanimate, without life) Selection factors are based on the inanimate environment, ie on physical and chemical influences