The document summarizes key concepts in ecology. It discusses the biosphere and levels of biological organization. It describes biotic and abiotic factors, ecosystems, niches, communities, populations, and species. It explains habitats, symbiosis, and how organisms obtain energy. It outlines food chains, webs, and ecological pyramids. Finally, it briefly discusses nutrient, water, nitrogen, and carbon cycles.

1. Chapter 2 Ecology

7. Species

8. Population

9. Community

25. Section 2.2 Summary – pages 46 - 57 Sun-Producers-Consumers-Decomposers- Released as heat Autotrophs First-order heterotrophs Third-order heterotrophs Second-order heterotrophs Decomposers

27. Food Web: Interconnected, overlapping food chains

28. Food Web

32. Different Types of Pyramids

35. Water Cycle

38. Carbon Cycle