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Lecture 7 - And 2 aquatic Biomes(marine&amp...

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Lecture 7 (9/1/10) Food Webs Biomass Pyramids Biomass is the weight of living matter The first feeding (trophic) level is the producers, which capture energy from the non-living environment Consumers derive energy from the chemical energy stored in the bodies of producers or other consumers Biomass declines with each higher trophic level because progressively less food is available In general, 80-95% of stored energy is lost in the transfer between each level Figure 3-23 Ecosystem Productivity Net Primary Productivity (NPP) = rate at which producers create biomass NPP varies greatly with the type of ecosystem (Table 3-5) Nine Major Biomes A biome is a large-scale category that includes many communities/ecosystems of a similar nature Biomes are largely determined by climate, especially temperature & rainfall There are 7 major types of terrestrial biomes 1. Tundra 2. Grassland 3. Savanna 4. Desert 5. Taiga 6. Temperate Forest
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Unformatted text preview: And 2 aquatic Biomes (marine & freshwater) Measuring Biodiversity There are several definitions of biodiversity A commonly accepted approach is to measure biodiversity by counting the number of species in a given area (species richness) Species richness changes with the area sampled Species-area curve used to-Compare biomes-Predict biodiversity in unexplored areas-Predict extinctions due to loss of habitat-Figure 4-6 Biodiversity Loss Community Degradation-Decline in the number of species in an ecosystem-Lower diversity leads to an easier disruption-Ecosystem health can be defined by indicator species Ecological extinction-A species is too rare to have an impact on its ecosystem Extirpation -A species has died out in a local area Extinction-The complete loss of a species-Background extinction rate- 2 to 10 species per year-Table 11-4...
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