Ecology

1. Ecology Community Interations

2. Community Interactions • An ecological community consists of all the interating populations within an ecosystem, in other words, community is the biotic component

3. Competition • What are the effects of competition among species? • Harmful ? • Beneficial ?

4. Competition • What is interspecific competition? • Two or more species attempt to use the same limited resources, particularly food and/or space • In interspecific competition, each species involved is harmed, because access to resources is reduced.

5. Competition • The severity of the harm is determined by the level of overlap in ecological niches of the two competitors. • An ecological niche encompasses all aspects of its way of life.

6. Competition • Adaptations reduce the overlap of ecological niches among coexisting species • Just as two objects can’t occupy the same space at the same time, two species can’t occupy the same ecological niche at the same time, competitive exclusion principle • Put two species of the same niche in an ecosystem and one will die out

7. Competition • This is true if the niches they occupy are static, but this is not true. • In this situation resource partitioning may come into effect • Each of the competing species reduces it’s niche in order to survive

8. Competition • Because individuals of the same species generally occupy the same niche intraspecific competition is a major factor in controlling population size. • A predator is anything that’s eats another organism, killing it in the process. (what might this include?)

9. Predation • Due to thier natural relationship predators and prey exert coevolutionary forces on each other. • One wants to hunt more efficiently • The other wants to stay alive

10. Predation • Examples of coevolution • Camouflage • Warning coloration (wasp) • Mimicry (stick insect) • Aggressive mimicry (predator) • Startle coloration (false eyes) • Chemical warfare

11. Symbiosis • Symbiosis – which literally means “living together” is defined as a close interaction between organisms of different species for an extended time. We will discuss three types of symbiosis • Commensualism • Mutualism • Parasitism

12. Symbiosis • Commensualism – is a relationship in which one species benefits while the other is relatively unaffected • Barnacles that attach themselves to the skin of a whale, for example, get a free ride through nutrient-rich waters without harming the whale

13. Symbiosis • Parasitism – one organism benefits by feeding on another • Things such as tapeworms, fleas and numerous disease-causing protozoa, bacteria, and viruses.

14. Symbiosis • Mutualism – when two species interact in a way that benefits both. • The clown fish takes shelter among the venomous tentacles of the anemone, which are harmless to it. The fish derives shelter and protection and , at least occasionally, it brings bits of food to its anemone