The Environment and the Biosphere

Biosphere Interactions

​

Key Ideas

• Producers transfer energy to consumers and decomposers.

• Interactions are needed to provide a constant flow of energy to sustain the biosphere

• Water, Carbon, Nitrogen, and Phosphorous cycle through our environment in many ways

Food Chain

• Producers: Living things that make their own food to get the energy they need 

• Consumers: Living things that eat producers or other consumers to get the energy they need 

• Decomposers: living things that break down dead organic material to get the energy they need 

Energy Pyramid

• A model that shows the amount of energy available in each level of a food chain 

Nutrient Cycles

Water Cycle

• Evaporation: Heat from the Sun causes water at Earth’s surface to evaporate

• Condensation: As warm air rises, it cools and condenses, forming clouds

• Precipitation: Water falls back to Earth’s surface when it rains or snows

• Water moves over Earth’s surface (“run-off”) and moves downhill back into the ocean water due to gravity

Human Impact

• Water pollution: Any physical, biological, or chemical change in water quality that has an adverse effect on organisms or that makes water unsuitable for desired uses 

Karma

• Bioaccumulation: the process by which pollutants collect in the cells and tissues of organisms 

• Biomagnification: the increase in concentration of pollutants in tissues of organisms that are at successively higher levels in a food chain or food web 

Carbon Cycle

• Carbon dioxide moves through atmosphere and enters biosphere via photosynthesis and cellular respiration

• Carbon enters the atmosphere when we burn fossil fuels or when things die and decay

• Carbon enters the geosphere when organisms decay and get stuck in sediment

Nitrogen Cycle

• Nitrogen is a nutrient that cells need to build proteins

• Nitrogen makes up 78% of air, but organisms cannot use this form of nitrogen

• Nitrogen-fixing bacteria in soil and water change nitrogen into forms that plants can use

Nitrogen Cycle

• Nitrogen Fixation: N₂ (atmosphere) turns to other forms like NH₃ (lightning and microorganisms)

• Nitrification: NH₃ to NO₂ and NO₃ (oxidized by microorganisms)

• Denitrification: NO₃ to N₂ (reduced by microorganisms)

Phosphorous Cycle

• Phosphorus is a nutrient essential for the growth and development of organisms

• Phosphorus is stored in the geosphere

• Plants absorb the phosphorus, and animals obtain it when they eat plants and other animals

• Decomposers return phosphorus to soil and water as they break down dead organisms

Excess Phosphorous

• Excess phosphorus is due to human activities (detergents, fertilizers, other wastes)

• Can cause serious environmental concerns

• Eutrophication is a natural process that results from accumulation of nutrients in lakes or other bodies of water