The major type of variation caused in the morphology of an individual is a combination of both environmental factor influence and genetic variation. In this type, the diet factor of individuals along with the kind of regular environment it is exposed to in addition to the biological clock the organism follows is considered. So, the eventual result of this type leads to selection by the nature based on the genetic organization of the individual under influence of the environment. The other type of variation is purely genotypically based in which the change in the genotype decides the result of the phenotypic variation of an individual. Another type does not rely on any of either factor-like external environment influence or the genotypic make-up of the individual to decide the phenotypic variation. This type of variation is based on the developmental system of the organisms. Apart from all the mentioned variation, there is a type of phenotypic variations that are genetically fixative and cannot be altered by any means such as remain adaptively fixative and show no selection based on phenotypic variation.
Causes of Phenotypic Variation
The causes for the phenotypic variation are to survive in the changing environment as a mechanism of defense. Another cause for phenotypic variation is the reduction in fitness of an individual due to any environmental influence to help it survive by causing variation in the population.
Genetic variations of individuals are also a cause of phenotypic variation as they are already different on the genetic level so their features of expression will be different as well. The patterns are predetermined at the genetic level making them phenotypically different. The lack of the factors controlling genes at the embryonical level also leads to phenotypic variations in the organism. The pattern of development of an individual decides the phenotype of the organism which is aligned according to an ancestral lineage that decides the external morphology of the individual.
Effects of Phenotypic Variations
All the causes of the phenotypic variations lead to the effects shown by all the organisms including plants and animals and even microorganisms. Due to the combination of environmental influential factors, the genetic make-up of an organism and changes at the basal level of development tends to cause effects like plasticity that is of three types called adaptive, injurious, and neural plasticity. Adaptive plasticity changes their pattern for the environment helping them to survive. In addition to this, they obtain differences at the genetic level, fixed determined pattern for development, and genetic constraints that are regular and continuous in a kind of organism showing specific phenotypic variation.