1. Ecological Principles Part II PaCES/HIMB Summer Program in Environmental Science David A. Krupp, Ph.D PaCES/HIMB Summer Program in Environmental Science David A. Krupp, Ph.D

2. Topics to be Studied Competition between species Predator-prey relationships Symbiosis Species diversity Trophic relationships Ecological succession Productivity Energy flow Biogeochemical cycles Competition between species Predator-prey relationships Symbiosis Species diversity Trophic relationships Ecological succession Productivity Energy flow Biogeochemical cycles

3. Competition Among Species

4. Ecological Niche Concept Ecological niche = the "role" a species "plays" in the ecosystem. Contrast the ecological niche with the "habitat" which is the physical environment in which the organism lives. Ecological niche = the "role" a species "plays" in the ecosystem. Contrast the ecological niche with the "habitat" which is the physical environment in which the organism lives.

5. Ecological Niche Concept The ecological niche of a species, therefore, includes not just the species’ habitat, but also the ways in which it interacts with other species and the physical environment.

6. Competitive Exclusion Principle No two similar species occupy the same niche at the same time

7. Possible Outcomes of Competition Extinction of one species Resource partitioning: splitting the niche Character displacement: two similar species evolve in such a way as to become different from each other by accentuating their initial minor differences Extinction of one species Resource partitioning: splitting the niche Character displacement: two similar species evolve in such a way as to become different from each other by accentuating their initial minor differences

8. Extinction of One Species

9. Competition in Nature

11. Resource Partitioning

12. Character Displacement

13. Predator-Prey Relationships Possible Outcomes offset oscillations in the population sizes of the predator and prey evolution of prey adaptations that minimize predation evolution of predator that enhance predator’s ability to obtain prey coevolution of predator and prey offset oscillations in the population sizes of the predator and prey evolution of prey adaptations that minimize predation evolution of predator that enhance predator’s ability to obtain prey coevolution of predator and prey

14. Oscillations in Predator and Prey Populations

15. Symbiosis Mutualism Both the symbiont and host benefit (+/+) Commensalism The symbiont benefits with little effect on the host (+/0) Parasitism The symbiont benefits to the detriment of the host (+/-) Mutualism Both the symbiont and host benefit (+/+) Commensalism The symbiont benefits with little effect on the host (+/0) Parasitism The symbiont benefits to the detriment of the host (+/-)

16. Symbiotic Relationships Mutualism coral and zooxanthellae ants and acacia trees

17. Symbiotic Relationships Commensalism cattle egrets and water buffalo

18. Symbiotic Relationships Parasitism endoparasitic liver fluke ectoparasitic monogenetic fluke

19. Species Diversity & Evenness

20. Keystone Species A species whose presence in the community exerts a significant influence on the structure of that community

21. Keystone Species

22. Trophic Levels 1st Trophic Level = Primary Producers 2nd Trophic Level = Herbivores or Primary Consumers 3rd Trophic Level and Higher = Carnivores or Secondary (or higher) Consumers Highest Trophic Level = Top Carnivore Decomposers 1st Trophic Level = Primary Producers 2nd Trophic Level = Herbivores or Primary Consumers 3rd Trophic Level and Higher = Carnivores or Secondary (or higher) Consumers Highest Trophic Level = Top Carnivore Decomposers

23. Simple Food Chains primary producer primary consumer secondary consumer tertiary consumer

24. Food Webs

25. Ecological Succession The progressive change in the species composition of an ecosystem.

26. New Bare Substrate Colonizing Stage Successionist Stage Climax Stage Ecological Succession

28. Primary Versus Secondary Succession

29. No Disturbance (Competitive Exclusion Model) Occasional Strong Disturbance (Intermediate Disturbance Model) Constant Strong Disturbance (Colonial Model) No Disturbance (Competitive Exclusion Model) Occasional Strong Disturbance (Intermediate Disturbance Model) Constant Strong Disturbance (Colonial Model) Successional Models and their Impacts

30. Primary Production Primary production = the amount of organic matter produced by autotrophs Usually restricted to production by photoautotrophs (photosynthesis), but can also include production by chemoautotrophs (chemosynthesis) We will restrict the discussion to primary production due to photosynthesis Primary production = the amount of organic matter produced by autotrophs Usually restricted to production by photoautotrophs (photosynthesis), but can also include production by chemoautotrophs (chemosynthesis) We will restrict the discussion to primary production due to photosynthesis

31. Factors Influencing Primary Productivity Light Light intensity Spectral distribution Temperature Evapotranspiration Inorganic nutrients Light Light intensity Spectral distribution Temperature Evapotranspiration Inorganic nutrients

32. Primary Production Gross primary production (GPP) = the amount of light energy converted into chemical energy by photosynthesis Respiration (R) = consumption of chemical energy by primary producers Net primary production (NPP) = chemical energy stored in primary producers after respiration Gross primary production (GPP) = the amount of light energy converted into chemical energy by photosynthesis Respiration (R) = consumption of chemical energy by primary producers Net primary production (NPP) = chemical energy stored in primary producers after respiration

33. % Earth’s Surface Primary Productivity of Different Ecosystems NPP/m 2 /yr% Earth’s NPP open ocean reefs & algal beds tropical rain forest swamp & marsh

34. Energy Use by an Herbivore feces respiration growth

35. plants herbivores carnivores decomposers Energy Flow Through Ecosystems

36. Energy Pyramids

37. Pyramid of Numbers

38. Biomass Pyramids

39. carbon dioxide inorganic-C plants organic-C animals organic-C decomposers organic-C death eating photosynthesis respiration The Carbon Cycle

40. death animals organic-N decomposers organic-N eating nitrate inorganic-N plants organic-N inorganic nitrogen uptake ammonia inorganic-N nitrification The Nitrogen Cycle (Part I) inorganic-N nitrite ammonification

41. nitrate inorganic-N N2N2 N2N2 denitrification ammonia inorganic-N nitrification The Nitrogen Cycle (Part II) inorganic-N nitrite nitrogen fixation

42. Generalized Biogeochemical Cycles