animalbehaviorsbirdscarbohydratescellcellscellularcomparingcomplexcycledarwindensitydependentdiffusiondiversitydnaearlyenergyenzymeequationevolutionexamplesexpressionfinchesfoodfunctiongenegeneticgeneticsgrowthinheritancelifelinkedlipidsmacromoleculesmeiosismembranemetabolicorganellesosmoticoverviewoxidationpathwaysphosphorylationplantpopulationpressureproteinproteinsreactionsreceptionreceptorsregulationrelationshipsrespirationrnaselectionsignalingskinkstructuresystemtransductiontransportwater