How could the gain or loss of the species of owl affect the ecosystem

Without owls the food chain will be off balanced. Also some animals will become over populated. These animals are important to farmers because they kill/eat rodents that kill the farmers crops and helps keep balance in the food chain. [Google]

Owls that feed in agricultural areas provide benefits to humans by killing large numbers of small rodents which might otherwise eat crops in the field or in storage. Barn Owls are specialist birds and highly adapted to suit their ecological role as hunters of small mammals in open habitat and low light conditions.Oct 4, 2011

Explanation:

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.