This 6-8 lesson unit is designed around the Big Idea that " The biosphere, geosphere, hydrosphere, and atmosphere are interconnected, as matter cycles and energy flows through them.āGraphically organized gap notes accompany powerpoint that introduce Earth's Spheres & Ecology. Topics covered:Earths Spheres - atmosphere, biosphere, cryosphere, geosphere & hydrosphereTrophic categories & levels, food chains, food webs, ecological pyramidAbiotic & biotic components of an ecosystemNutrient cycles -