A love, hate thing…

 Every organism in an ecosystem has a role or job to carry out… That job and how it uses the conditions around it is called a niche Examples include:  an organism’s place in the food web; producer, consumer, decomposer.  How it interacts with other living things (biotic factors)  Where and how it lives out its life  Resources (abiotic factors) that affect it.

 Competition  Predation: predator and prey  Symbiosis Mutualism Commensalism Parasitism

 Competition exists between members of the same species and between species.  What are organisms competing for? Resources: food, water, living space, etc.

 Contrary to common thought…  An organism won’t eat all the prey. What would happen to the predator

 Sym; together  Biosis: living  Symbiosis is defined as a “relationship when two organisms live closely (in or on) together.  Three types

 I’ll scratch your back if you scratch mine…

 When one member in the relationship is benefited and the other…well no harm, nor help

 One member is helped by the relationship and the other is harmed.

 Orderly, natural changes and species replacements that take place in the communities of an ecosystem.  Often follows a predictable, orderly pattern.  Two types: Primary and Secondary

 Step 1 - Bare rock (0-1 years) Lichens grow on the bare rock (a pioneer species). As they die, the decaying lichens form soil so moss can grow.

 Step 2 - Grassland (2-4 years) Grasses and other small plants grow; out-competing the mosses for sunlight.

 Step 3 - Transitional or shrub (5-20 years) Small shrubs such as dogwood and sumac begin to dominate.

 Step 4 - Coniferous Forest ( years) Pines and fir trees begin to shade out the smaller shrubs

Pine forest

 Step 5 - Deciduous Forest ( years) Large, slow-growing trees such as oak, maple and hickory replace the pines…if the abiotic factors “allow” it to happen.

 Succession that occurs after a community is disrupted by natural disasters or human activity. Examples = fire, flood… *Occurs in a shorter amount of time because soil and sometimes seeds present.

Yellowstone National Park (after a 1988 forest fire)

Southern WI = Prairie Baraboo = deciduous forests Northern Wa = temperate rainforest in Olympics