Ecosystems
What is an ecosystem? Ecology-the study of interactions of living organisms with one another and with their physical environment Ecosystems are complex and defined by many smaller parts combined to form the whole
Habitat-the place where a particular population of a species lives Community-the many different species that live together in a a habitat Ecosystem-consists of a community and all the physical aspects of a habitat
Abiotic vs. Biotic Abiotic Factors-nonliving factors of an ecosystem Biotic Factors-living factors of an ecosystem Biodiversity-the total number of species living within an ecosystem
Ecosystems Change Over Time Ecological Succession is the change of ecosystems over time Primary Succession-succession where plants have never grown Secondary Succession-succession where plants have previously inhabited an area
Primary Succession
Climax community?? May take 100’s or 1000’s of years to reach this stage Stage at which system has reached steady-state equilibrium Most permanent of all the stages Difficult to identify
Disturbance They damage biological communities Include events such as storms, fires, floods, droughts, overgrazing, and human activities They damage biological communities They remove organisms from communities They alter the availability of resources
Intermediate Disturbance Hypothesis If widespread disturbances occur frequently, diversity will be limited If diversity is high, only moderate disturbances have been occurring with moderate frequency
Energy Flow in Ecosystems Most life of Earth depends on photosynthetic organisms Primary Productivity-the rate at which organic material is produced by photosynthetic organisms Producers- organisms that capture solar energy Consumers- organisms that consume food
Trophic Levels Trophic Level- a graphic organizer based on an organism’s source of energy Primary Producer, Primary Consumer, Secondary Consumer, Tertiary Consumer, Quaternary Consumer
Food Chain vs. Food Web A food chain shows an incomplete path of NRG A food web shows a more realistic path of NRG
What Do You Eat? Herbivore- plants Carnivore- other organisms Omnivore- plants and animals Detritivore- organic wastes and dead bodies Decomposer- cause decay
Productivity Rule Ecosystems are generally more productive near the equator More NRG available for living organisms NRG Pyramid-diagram in which each trophic level is represented
Rule is only about 10% of NRG actually gets transferred to the next trophic level