 The study of organisms and their interactions with other organisms and their environment

 Individual organism  Population of organisms  Community: different species in same space  ecosystem

 The study of the number and distribution of a population of organisms through space and time  Knowledge of the factors contributing to the population number is critical

 Water  Light  Air  Minerals  Temperature  Elevation  Space  Insecticides  herbicides

 Living food  Predators  Parasites  Competitors (same species or other species)

 Water supply  Nutrient supply  Mating sites  Nesting/living spaces  disease

 Number of offspring enter barrel  Barrel has certain amount it can hold (carrying capacity)  Many factors keep the population from reaching carrying capacity

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 Competition: struggle for the same food, territory, mates, etc. among members of the same species or different species  Predation: when one species relies upon another for food  Migration: movement of a population during different times of the year

 Parasitism- one organism benefits the other is often harmed.  commensalism - one organsim benefits from the relationship but the other is not affected or harmed.  Mutualism- both organisms benefit from the relationship

 All energy of earth begins with the SUN  Sunlight reaches earth in 8.4 minutes  Sunlight comes in packets of energy called photons  Light energy is converted to potential chemical energy in the bonds of glucose (photosynthesis)  Heat energy is also part of light

Plants use sunlight to produce glucose as a source of energy. When a primary consumer eats a plant, it only gets 10% of the energy that the plant had available to it. This is the 10% law.

12. Food Chain: a group of organisms through which energy flows

Each level of this pyramid is called a TROPHIC LEVEL

13. Most organisms are involved not in just food chains, but in FOOD WEBS: complex interactions of organisms through which energy is passed.

 Carbon  Nitrogen  Sulfur  phosphorus

15. Carbon Cycle

16.

17.

 CAUSED BY HUMANS; RELATED TO HUMAN ACTIVITY

 Why is it important? ◦ Environment changes as species inhabit it- some become extinct in an area, some flourish ◦ Natural disaster may change the environment (earthquake, flood, fire) ◦ Man may change environment (clear cut forests, drain swamps, agriculture)

Mt. St. Helen: erupted on May 18, ash blown from the mountain top traveled hundreds of miles, coating and destroying much plant and animal life