1. Community Ecology Chapter 54

2. Community An assemblage of populations of various species living close enough for potential interactions

3. 54.1 Community interactions are classified by whether they help, harm, or have no effect on the species involved

4. Types of Interactions Interspecific Interactions Interactions with other species Intraspecific Interactions Interactions within one species

5. Ecological Niche Every species survives and reproduces utilizing a range of chemical and biological conditions Resource partitioning allows species to live in the same habitat by fulfilling different ecological niches

6. Competitive Exclusion Principle Direct interspecific competition will always lead to the extinction of one species One species will have a slight competitive edge in surviving and reproducing

7. Interspecific Species Interactions

8. Predation (+/-)

9. Predation Defense Strategies Cryptic coloration – camouflage Aposematic coloration – warning coloration Batesian mimicry – a harmless species mimics a harmful one Mullerian mimicry – two harmful species mimic each other

10. (a) Cryptic coloration(b) Aposematic coloration Canyon tree frog Poison dart frog (c) Batesian mimicry: A harmless species mimics a harmful one.(d) Müllerian mimicry: Two unpalatable species mimic each other. Hawkmoth Larva (harmless) Cuckoo bee Yellow jacket Green parrot snake (harmful)

11. Herbivory (+/-)

12. Parasitism (+/-)

13. Commensalism Commensalism (+/0)

14. Mutualism Mutualism (+/+)

15. Facilitation (+/+ or 0/+) One species influences the survival and reproduction of another species Ex: plant species that make soil hospitable for other species to thrive

16. 54.2 Diversity and trophic structure characterize biological communities

17. Species Diversity Species richness: Total amount of species in a community Relative abundance: Total amount of one species in a community Diversity is key to a healthy, stable ecosystem

18. Simpson’s Index of Biodiversity Mathematical method of measuring diversity Accounts for abundance and richness of species in an ecosystem

19. Trophic Structure Trophic structure: feeding relationships Represented by food webs, chains How energy flows through ecosystem! Decomposers cycle matter in ecosystem! Energy availability limits length of food chains 10% rule Biomass: amount of mass of individuals in a population

20. Keystone Species Organism with a pivotal role in an ecosystem Not necessarily, usually the dominant (most abundant) species! The removal of a keystone species results in the collapse of the ecosystem Ex: sea otter (Enhydra lutris)

21. 53.3 Disturbance influences species diversity and composition

22. Disturbance & Succession Disturbance – event that changes the dynamics of a community Succession – recovery of that community after a disturbance

23. Primary vs. Secondary Succession Primary – begins with rock Ex: glacier, volcano Secondary – begins with soil Ex: forest fire, flood Climax community – recovered, long term stability

24. Human vs. Natural Disturbance Humans – clearing land for own uses Ex: logging, agriculture Generally, no recovery to climax community

25. 54.4 Biogeographic factors affect community diversity

26. Abiotic shapes biotic

27. 54.5 Pathogens alter community structure locally and globally

28. Abiotic shapes biotic Pathogen: disease causing microorganism Zoonotic pathogen: pathogen of animal origin that are transferred to humans