1. Ecology: Ecological Interactions David Mellor, PhD Citizen Science Coordinator Virginia Master Naturalists

2. Overview of Ecology Definition and Scope Energy and Food Webs Nutrient Cycles Population Dynamics Ecological Interactions Community Structure Ecosystem Services Human Impacts

3. Ecological Interactions

4. Interactions When two organisms interact, each can either benefit (+), be harmed (-), or have no effect (o)

5. Interactions Interactions can occur between many different groups: Members of the same species Members of different species

6. Interactions +/+Mutualism -/-Competition +/-Predation, parasitism +/oCommensalism -/oAmensalism o/oNeutral

7. Mutualism +/+

8. Competition -/- Species can compete for any resource: – Food – Space/shelter – Water – Limiting nutrients

9. Competition -/- Within species Between species

10. Predation & Parasitism +/-

11. Commensalism +/o

12. Amensalism -/o

13. Indirect Interactions (trophic cascades) © 2010 Nature Education

14. Species Interactions Worksheet How would you show, experimentally, that two species interact? In other words, how do we know that species X and species Y compete with each other?

15. Interaction Experiments

16. Responses to Predation Animals – Aposematic Coloration – Camouflage and Countershading – Mimicry Plants – Secondary Compounds – Morphology – Mutualisms – Below-ground storage

17. Animal Coloration Mimicry Camouflage Countershading Aposematic: Warning Coloration

18. Plant Responses Morphological Secondary Compounds