Biology- Energy in biomass

Pyramids in biomass

• Radiation from the Sun is the main source of energy for living organisms
• Green plants and algae capture light energy during photosynthesis
• Biomass is the dry mass of living material in an organism
• The biomass at each stage in a food chain is less than at the previous stage

Energy transfers

• There is less biomass and energy available at each successive stage in a food chain
• Materials are used ar each stage and energy may be transferred to the surroundings
• There is energy wastage between each stage of a food chain. This means that not all of the energy taken in by an organism result in the growth of that organism
• Not all of the food eaten can be digested, so energy is stored in faeces or as urea in urine (waste materials)
• Some of the biomass (food) is used for respiration, which relases energy for living precesses. This includes movement, so the more something moves the more energy it uses and the less is available for growth
• In animals that need to keep a constant temperature, energy from the previous stage of the food chain is used simply to keep the animal as its normal body temperature

Decay processes

• Living organisms remove materials from the environment which are returned when the organism dies
• Microorganisms decay waste and dead plants and animals
• Decay is quicker in warm, moist, aerobic conditions
• Processes which use materials must be balanced by those which release them
• All organisms take up nutrients. If they didn't eventually release them, the nutrients would run out
• Detritus feeders (such as some types of worm) may start the process of decay by eating animals or plants and producing waste materials. Decay organisms then break down the waste or dead plants and animals
• Humans can recycle waste in sewage treatment plants and compost heaps

The carbon cycle

• The constant cycling of carbon in nature is known as the carbon cycle
• During photosynthesis carbon dioxide is removed from the atmosphere
• The processes of respiration and combustion return carbon dioxide to the atmosphere
• Green plants as well as animals repire. This returns CO2 to the atmosphere
• When humans cut down and burn trees,CO2 is released into the atmosphere
• Animals eat green plants and build the carbon into their bodies. When plants or animals die (or produce waste) microogranisms release the CO2 back into the atmosphere through respiration

Recycling organic waste

• Recycling organic kitchen and garden waste is necessary to: reduce landfill, reduce methane production, recycle minerals and nutrients in the waste
• There are various methods of recycling organic waste
• The most efficient methods of composting allow the waste to be mixed with oxygem and moisture. They also allow energy to escape by heating the surroundings
• Gardeners may add worms and layers of garden soil to composters to speed up the process
• Councils also collect garden waste and use shredders and large bins to compost the material
• A well-designed compost heap allows air (containg oxygen) in, heat out and has room for soil between the organic waste