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Community ecology
The document discusses community ecology, defining a community as an assemblage of species interactions. It highlights various species interactions, including competition, predation, parasitism, mutualism, and commensalism, and explains concepts such as ecological niches and resource partitioning. Additionally, it covers the impacts of these interactions on species coexistence and community structure.
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Community ecology
- 1. BY SURABHI TANWAR Masters Studentin the Environmental Sciences Institute of Science, Mumbai COMMUNITY ECOLOGY
- 2. What is aCommunity? It is an assemblage of species living close enough together for potential interaction. Communities differ in their species richness, the number of species they contain, and the relative abundance of different species.
- 3. FOUR main kindsof species interactions; all play a role in the formation of community structure... Competition (-,-) Predation, parasitism (+,-) Mutualism (+,+) Commensalism (+,0)
- 4. Competition. ◦ Interspeciescompetition: can occur when resources are limited.
- 5. Competition. ◦ Interspeciescompetition for resources can occur when resources are in short supply. There is potential for competition between any two species that need the same limited resource. ◦ The competitive exclusion principle: two species with similar needs for same limiting resources cannot coexist in the same place. G. F. Gause (1934) tested competitive exclusion principle
- 6. Ecological Niches Thetotal of a species’ use of biotic and abiotic resources is called the species’ ecological niche Ecologically similar species can coexist in a community if there are one or more significant differences in their niches As a result of competition, a species’ fundamental niche may differ from its realized niche
- 7. Fundamental Niche vsRealized Niche Fundamental Niche: the niche that a species potentially could occupy, in the absence of competitors. Realized Niche: the niche to which a species is restricted in the presence of competitors.
- 8. Classic experimentsconfirm this. Fig. 53.2
- 9. Resource Partitioning Resourcepartitioning is differentiation of ecological niches, enabling similar species to coexist in a community
- 10. Character displacement Body evolves as aresult of resource partitioning .
- 11. Predation. ◦ Apredator eats prey. ◦ Herbivory, in which animals eat plants. ◦ In parasitism, predators live on/in a host and depend on the host for nutrition.
- 12. Offset oscillationsin the population sizes of the predator and prey Coevolution of predator and prey
- 13. ◦ Plant defensesagainst herbivores include chemical compounds that are toxic. ◦ Animal defenses against predators. Behavioral defenses include fleeing, hiding, self- defense, noises, and mobbing. Camouflage includes cryptic coloration, deceptive markings. Fig. 53.5Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
- 14. Mechanical defensesinclude spines. Chemical defenses include odors and toxins Aposematic coloration is indicated by warning colors, and is sometimes associated with other defenses (toxins). Devil scorpionfish backside
- 15. In Batesianmimicry, a palatable or harmless species mimics an unpalatable or harmful model monarch viceroy
- 16.
- 17. In parasitism,one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process Parasitism exerts substantial influence on populations and the structure of communities Mutualism is where two species benefit from their interaction. Coral polyp & zooxanthellae Commensalism is where one species benefits from the interaction, but other is not affected.
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