Energy Flow and Environmental change Flashcards
How is energy lost in a food chain/web from producer onwards. (5 marks)
All organisms respire and respiration releases energy.
Some energy is lost in animals waste materials.
Some energy used in maintenance / repair.
Some energy used for movement.
Some energy lost as heat to surroundings.
Some organisms die (rather than being eaten)
Describe an experiment you could carry out to show how lichens can be used to indicate the levels of pollution as you move out of a city. (3 marks)
Measure the number of different lichens in the city then at set intervals moving away from the city. If lichens increase and different types appear then pollution is decreasing.
Rat tailed maggots are poor competitors. Suggest why they do not survive well in clean water. (2 marks)
Rat-tailed maggots are poor competitors, which means that other organisms are better adapted to compete efficiently for all the resources, such as food and space, in clean water.
What is biomass?
Biomass is the mass of living material in plants and animals.
What is a pyramid of biomass?
A pyramid of biomass represents the mass of the organisms at each stage in a food chain. It may be more accurate than a pyramid of numbers. For example, one bush may have many insects feeding on it but the mass of the bush is far greater than the mass of the insects.
Where doe the energy come from which starts every food chain?
Green plants transfer solar (light) energy to chemical energy which is then passed through the food chain.
Not all of the energy taken in by an organism results in the growth of that organism. Why? (4 marks)
Not all of the food 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 releases energy for living processes. This includes movement, so the more something moves the more energy it uses and 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 up simply to keep the animal at its normal body temperature.
Much of the energy released in respiration is eventually transferred to the surroundings.
What are the best conditions for decay?
Decay is faster if it is warm, moist. Most decomposers respire and so decay takes place more rapidly when there is plenty of oxygen.
What are decomposers?
Decomposers are a group of microorganisms that include bacteria and fungi. They feed on waste droppings and dead organisms.
What are detritus feeders and how do they help in the process of decay? (2 marks)
Detritus feeders (such as maggots and some type of worms) may start the process of decay by eating dead animals or plants and produce waste materials
In the Carbon cycle what does Photosynthesis do to carbon and what form is it in?
Photosynthesis removes CO2 from the atmosphere.
How is Carbon dioxide returned to the atmosphere?
Green plants as well as animals respire. This returns CO2 to the atmosphere.
Combustion of fossil fuels releases CO2 into the atmosphere.
Animals eat green plants and build the carbon into their bodies. When organisms die (or produce waste) microorganisms release CO2 back into the atmosphere through respiration.
What are the best conditions for composting and why?
4 marks
The most efficient methods of composting allow the waste to be mixed with oxygen and moisture. They allow energy to escape by heating the surroundings.
Gardeners may add worms and layers of garden soil to composters to speed up the process.
What living thing is a good indicator for air pollution?
Lichen
Is all material passed through a food chain?
No some remains uneaten and is left to decay
