Notes on ecosystems and biomes

Our discussion of chapters 19 and 20 in the textbook will focus on some basic principles of ecology, structure and function of ecosystems, and the spatial pattern of major terrestrial biomes in relation to the pattern of global climates. The following outline highlights the major points covered.

Chapter 19

• Ecosystem, community, habitat and niche
• Types of relationships among populations: predator-prey, competition, symbiosis or mutualism, parasitism
• Primary producers and their principle characteristics
• Leaves and stomata
• Photosynthesis and respiration (expressed as simple chemical equations)
• Net vs. gross primary productivity and biomass
• Global comparisons of net primary productivity among biomes
• Role of climatic factors (primarily light, temperature and precipitation) in spatial distribution of plant communities
• Latitudinal and vertical zonation
• Biogeochemical cycles for major elements: oxygen, carbon,, nitrogen
• Limiting factors
• Structure of trophic webs or food webs:
• primary producers (autotrophs)
• primary, secondary, tertiary consumers (heterotrophs)
• decomposers
• efficiency of energy conversion and the ecological pyramid
• Concepts of ecosystem stability, diversity, and succession
• Adaptation of plant communities to environmental change
• Ecology of disturbance, including fire

• Terrestrial ecosystems and the biome concept
• Large marine ecosystems
• Major growth forms of vegetation
• Major terrestrial biomes and their correspondence to climate types:
• Equatorial/tropical rainforest
• Tropical seasonal forest/savanna
• Midlatitude broadleaf (deciiduous) and mixed forest
• Needleleaf or conifer forest (taiga) and its montane varieties
• Temperate rain forest
• Mediterranean shrubland and chaparral
• Midlatitude grassland and steppe
• Warm and cold deserts
• Arctic and alpine tundra