The document discusses several key concepts in ecology including: - Producers (autotrophs) obtain energy through photosynthesis or chemosynthesis and are the base of the food chain. - Energy and matter cycle through ecosystems in food chains and webs with producers as the first trophic level and multiple consumer levels above. - Nutrients like carbon, nitrogen, and phosphorus cycle through ecosystems via biogeochemical cycles as they pass between organisms and the environment.

1. Biology

3. Levels of Organization Ecosystem Community Population Individual Biome Biosphere

6. 3–2 Energy Flow

33. Ecological Pyramids 50 grams of human tissue 500 grams of chicken 5000 grams of grass Biomass Pyramid: Represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid.

35. Ecological Pyramids Pyramid of Numbers: Shows the relative number of individual organisms at each trophic level.

37. 3–3 Cycles of Matter

49. Nutrient Cycles CO 2 in Atmosphere Photosynthesis feeding feeding Respiration Deposition Carbonate Rocks Deposition Decomposition Fossil fuel Volcanic activity Uplift Erosion Respiration Human activity CO 2 in Ocean Photosynthesis

52. Nutrient Cycles Bacterial nitrogen fixation N 2 in Atmosphere NH 3 Synthetic fertilizer manufacturer Uptake by producers Reuse by consumers Decomposition excretion Atmospheric nitrogen fixation Uptake by producers Reuse by consumers Decomposition Decomposition excretion NO 3 and NO 2

61. 5-1 How Populations Grow

72. 5-2 Limits to Growth

81. Wolf and Moose Populations on Isle Royale Moose Wolves

85. 5-3 Human Population Growth

98. Future Population Growth