 Community: group of interacting populations in a certain area at same time  Communities can be different, they can be different species (plant or animal)  They can be difficult to live in too  Too much of something, too little

 Limiting factors: any biotic or abiotic factor that restricts the existence, numbers, or reproduction of an organism  they control what lives in a environment  Ex:  Temperature  Precipitation (water)  Disease  Space  Food/predators

 Tolerance: the ability of an organism to withstand (tolerate) changes in an environment  what are your ranges of tolerance?

 Succession: natural changes in an environment that occur over time  Refers to natural growth of plants/trees/etc  2 types  Primary  Secondary

 Primary succession: the colonization of barren land by communities of organisms  Done by “pioneer species”  Moss  Lichen  No animals present, no soil present  Occurs on rock  Lichen breaks down rock to form soil so other plants and shrubs can grow

 Primary succession leads to a climax community  a stable, mature, community that undergoes little to no change  Plant life has reached it’s peak in growth

 Secondary succession: occurs after some sort of natural disaster or human caused interruption  Forest fire  Habitat destruction  Soil and animal life already existed there  Does not involve pioneer species  Will also lead to a climax community