What percent of biology study is dedicated to species-specific subjects like ecology and evolutionary biology?
I'm thinking of studying biology... 


Did you have gone through the basic (school) level of biology and chemistry? otherwise the concepts may become hard to handle. 


  especially ecological and evolutionary biology 


Ecology and evolutionary biology is in fact highly information-dependent area. 

Ecology is the study of habitat, lifestyle and interrelationship of different organisms. So there will come the role of different organisms in ecological relationships. 

But there are other parts like statistical calculation of gene frequencies, energy uptake, etc. These parts will contain lesser amount of species-specific information. 

Evolutionary biology too; have various fields and aspects, and could be studied in various ways. 

If you need to study about evolution of a certain genera with fossil evidences; or estimate  the evolution of biochemical pathways; a lot of species or genus-specific information may require. 

Whereas there are generalized areas, such as basic principles of evolution, its mechanisms, statistical models, etc. 

(update coming soon...)