Variation

Genotype of an organism is the genetic makeup and collection of alleles that the organism has inherited from its parents. The phenotype of an organism is the collection of observarable features that it has.

Variation between different species is interspecific variation 

Variation between members of a species is intraspecific variation 

Interspecfic variation 

• Differences due to DNA 
• The structure and sequence of the genes in each organism
• The way in which the genes are expressed 

Intraspecific variation 

There are two types of intraspecific variation, discontinuous and continuous 

Discontinuous features fall into one category or another. The human ABO blood group for example. And usually controlled by single alleles. 

Continuous is where the features vary and show a whole range of values. Most the…