Community Interactions  Three types of interactions –Competition –Predation –Symbiosis  Mutalism  Parasitism  Commensalism

Competition- competing for resources  occurs due to a limited number of resources  Resource- any necessity of life. water, nutrients, light, food.  Competitive exclusion principle- no two species can occupy the same niche in the same habitat at the same time

Predation  Predation- when an organism captures and feeds on another organism.  Predator- hunter  Prey- hunted

Symbiosis  Symbiosis- any relationship where two species live closely together. (3 types) –Mutualism –Commensalism –Parasitism

Symbiosis - Mutualism  Mutualism- both species benefit from a relationship.  Lichens (fungus and Algae) One example is the lichens, little non-descript patches of stuff you see growing on rocks and tree bark. This is a symbiosis, consisting of a fungus and an alga. The fungus provides a protective home for the algae, and gathers mineral nutrients from rainwater and from dissolving the rock underneath. The alga gathers energy from the sun. There are thousands of species of lichen in the world; actually thousands of species of fungi with just a few species of algae which can form a partnership with almost any of them.

Symbiosis - Mutualism  Mutualism- both species benefit from a relationship.  Mychorrizae (plant and fungus) One example is the mychorrizae – the fungus embeds itself in the roots of the plant and provides additional Surface area for absorption of nutrients. In return, the plant provides a place for the fungus to live as well as Sugars from photosynthesis that are stored in the roots.

Symbiosis - Commensalism  Commensalism – One member of a symbiotic relationship benefits and the other is neither helped or harmed  Ex. Holes used by bluebirds in a tree were chiseled out by woodpeckers after it has been abandoned.

Symbiosis - Parasitism  Parasitism- One creature benefits and one creature is harmed  Ex tapeworm. Feeds in a humans intestines absorbing his/her nutrients.

Relationships:Symbiosis = Living Together a) commensalism b) mutualism c) parasitism

Identify these relationships