2. Community  Collection of species populations  Members from most kingdoms  Linked in a web  Mainly predator/prey  Environment & habitat / Dominant species  Lake/grassland  Sizes

3. Habitats and Niches  Habitat: A collection of niches  Habitat  Physical space where an organism lives  Microhabitats  Niche  The unique position occupied by a particular species in a community – ecological role  Each niche unique  Occupy overlapping BUT different niches  Fundamental vs. realized niche  Resource partitioning  Darwin’s finches

4. Darwins’ Finches

5. Patchiness  Distribution patterns  Random  Aggregated  Conditions & resources not evenly distributed  Temporal variability  Intraspecific & interspecific competition  Events  Gradient  Regular

6. Plankton patchiness  Horizontal, temporal & vertical variability  Physical - Water movements  Biological – plankton related  Light – dark cycle  Gamete concentration  Predator – prey interactions

7. Trophic interactions and productivity  Primary producers, consumers, decomposers  Rule of 10%  Different communities w/ different# of trophic levels  NPP

8. Net Primary Production

9. Trophic interactions and productivity  Guilds  Overlapping niche requirements  Keystone species  Limpets  Dominant  Numerical or biomass abundance  Opportunistic species, specialization, generalists

10. Measuring Productivity  6CO 2 + 6H 2 O  C 6 H 12 O 6 (glucose) + 6O 2  Increase in biomass over a fixed time period  NPP  Plankton

11.  Chylorphyll abundance  Secondary production Measuring Productivity

12. Comparative Ecosystem Productivity  Productivity determinants  Light, temperature, rainfall, nutrients  Tropics, higher latitudes, deserts  Photosynthetic efficiency  1-2 % in terrestrial ecosystems – 0.5 % in aquatic habitats  Conditions for plant growth not met  More secondary production in oceans  Detritivores

13. Trophic Interactions & Pollution  Material transfer  Minerals, vitamins etc.  Pollutants  Heavy metals, organic chemicals, some light elements  Bioconcentration  Biomagnification  Biotransformation  Mercury  methyl mercury

14. Mercury Pollution  Minimata disease, brain damage, kidney damage etc.  Organic methyl mercury  Bioconcentration & Biomagnification

15. Succession  The change in composition and form of vegetation  Immature  mature/self-sustaining  Primary Succession  Pioneer species  Xerarch vs. hydrarch succession  Secondary succession  Climax community

16. Xerarch vs. hydrarch succession

17. Succession

18. Biodiversity  Species & genetic & ecosystem diversity  biodiversity  Ecological diversity  Species diversity  Genetic diversity  Species richness vs. species diversity  Tropical forests, coral reefs and tropical lakes  Genetic diversity  Habitat destruction, pollution and agricultural practices

19. Stability and Resilience  Stability – environmental change  Persistence, constancy, resilience  High diversity = high stability?  Tropical rainforest vs. grasslands

20. Biogeography  Study of the distribution of organisms  Historical & Ecological  Vicariant and dispersal distribution  Endemic taxa  Six major zones