Biology 20 Energy and Matter Exchange in the Biosphere

The Biosphere  refers to all areas of the earth in which living organisms are found. This includes: –Atmosphere – air –Lithosphere – land –Hydrosphere – water

The Biosphere Biotic components – are the biological or living components of the biosphere, include all living things.  Ex. bacteria, fish, birds, mammals, plants Abiotic components – are the non-living components of the biosphere, include all chemical and physical factors.  Ex. Temperature, weather, soil acidity, sunlight

Incoming Solar Radiation

 Energy with be reflected or absorbed once it enters the atmosphere.  The colour of a surface affects the amount of energy it will absorb or reflect.  Dark surfaces absorb energy, and lighter surfaces reflect energy.  The reflectivity of a surface is known as its albedo.

 A snow covered field has a high albedo. It may reflect 70-80% of the energy striking it.  During the summer, the same field growing crops will have a lower albedo. It will reflect only 20% or less of the incoming energy.

Volcanoes and the Haze Effect  THE INFLUENCE OF VOLCANIC ERUPTIONS ON THE OZONE, GREENHOUSE, AND HAZE EFFECTS –Volcanic eruptions can enhance climate effects to variable degrees. –They contribute to ozone depletion, as well as to both cooling and warming of the earth's atmosphere.  - INFLUENCE ON THE HAZE EFFECT : –Volcanic eruptions enhance the haze effect to a greater extent than the greenhouse effect, and thus they can lower mean global temperatures. It was thought for many years that the greatest volcanic contribution of the haze effect was from the suspended ash particles in the upper atmosphere that would block out solar radiation.

Recent Volcanic Eruptions Recent Volcanic discoveries

Photosynthesis and Cellular respiration ENDOTHERMS (warm-blooded) animals and methods of survival

Energy flow through chains and webs

 Only part of the available energy from one trophic level can be transferred to the next. Assume that 10% of the energy available at a particular trophic level is transferred to the next.

Energy Transfer and Food Webs Living things can be categorized according to where they are in a hierarchy of energy.  Trophic Level – category that defines how living things gain energy for life processes. (feeding level)  Producers / Autotrophs – organisms that produce their own energy from either sunlight (photosynthesis) or chemical energy (chemosynthesis)

 Heterotrophs – organisms that feed on other organisms  Primary consumers – feed on autotrophs (herbivores)  Secondary consumers – feed on primary consumers (carnivores)  Top Carnivores – organisms that are not consumed by any other organism.

Food Webs  are interlocking food chains that illustrate more complex feeding relationships between organisms.

Scientific Models  Ecological Pyramids - can be used to represent the energy flow in food chains or food webs by showing the amount of energy, the number of organisms or the biomass. All pyramids illustrate the first / lowest trophic level on the bottom with successive trophic levels towards the top.

Pyramids of Energy – illustrates the decreasing amount of energy available at each successive trophic level.

Pyramids of Numbers – describe the number of organisms at each successive level of the food chain. These pyramids can often appear “inverted” when consumers are very small or producers are very large.

Pyramids of Biomass – represents the dry mass of plant and animal tissues in a food chain. The amount of dry mass decreases at each trophic level.

Here is a comparison of the three types of pyramids: