Biotic and Abiotic Factors Chapters 3.3, 4.2 and 6.3)

Biogeochemical cycles  the cycling of matter through the biosphere Hydrologic cycle (water cycle) Evaporation  liquid water is heated by the sun, turns into water vapor and rises into the air Condensation  Water vapor in the air cools and turns back into liquid water and forms clouds Precipitation  Liquid water falls back to Earth as rain, snow, sleet or hail Transpiration  plants lose water when they do photosynthesis

Nutrient Cycles Carbon Cycle  4 ways carbon moves through the biosphere Biological processes  respiration, photosynthesis, decomposition Geochemical processes  erosion, volcanic activity Mixed biogeochemical processes  burial and decomposition, production of fossil fuels Human Activities  mining, logging, burning fossil fuels and wood

Nitrogen cycle  majority of Earth’s atmosphere is nitrogen (N 2 ) Organisms cannot use N 2 Bacteria “fix” nitrogen in a process called nitrogen fixation Changes N 2 into NH3 (ammonia)

Factors that Shape Ecosystems Ecosystem vocabulary Biotic factors  living Abiotic factors  nonliving Habitat  the area where an organism lives Niche  the resources available to an organism and how that organism uses them

Community Interactions Competition occurs when several organisms try to use the same resources Predation occurs when one organism catches and eat another organism Predator  the organism that hunts Prey  the organism that is hunted

Symbiosis occurs when organisms live closely together Mutualism  both species benefit Yucca and Yucca moth Commensalism  one species benefits and the other not harmed nor helped Barnacles on a whale Parasitism  one organism lives in or on another and harms it Humans and Tapeworms

Changes in Ecosystems Ecological Succession is a series of changes over time after a disturbance Primary Succession  this occurs where there is no soil After a volcanic eruption The first species to show up after the disturbance is called a pioneer species Secondary Succession  occurs after a disturbance that does not destroy the soil Fire, flood, clear cut

Biodiversity Biodiversity  the variety of all life on the planet Ecosystem biodiversity  all the habitats, communities and ecological processes in the world Species Diversity  the number of different species in the biosphere Also called species richness Highest near the equator, lowest near the poles All organisms in the biosphere are linked

Threats to biodiversity Human activity can reduce biodiversity by altering habitats, hunting species to extinction, polluting and introducing foreign species into the environment Some of these activities lead to extinction Species that are at risk of going extinct are considered endangered Foreign species that reproduce quickly and threaten native species are called invasive species Conservation  wise use of natural resources, including preserving habitats and wildlife

Global Climate Change Gases in atmosphere help trap heat from the sun much like a green house  called green house effect Necessary for life Evidence of global warming Geological record shows Earth’s climate has changed repeatedly in history How have how human activities contributed to climate change? Increasing levels of CO 2 in the atmosphere Possible effects of global climate change Increase in average global temperature 1-2 C Could cause flooding of coastal areas as ice caps melt Increases in extreme weather Drought, snow, hurricanes Extinction of organisms that cannot adapt to new, higher temps.