AQA A2 Biology - Chapter 5 Energy and Ecosystems

Charlotte Lloyd
Flashcards by Charlotte Lloyd, updated more than 1 year ago More Less
Charlotte Lloyd
Created by Charlotte Lloyd over 4 years ago
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Flashcards on AQA A2 Biology - Chapter 5 Energy and Ecosystems , created by Charlotte Lloyd on 05/26/2015.

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Question Answer
What is a producer? Photosynthetic organisms which produce carbohydrates (glucose) from carbon dioxide using energy from the sun
What are consumers? - Distinguish between primary, secondary and tertiary consumers Organisms which obtain their energy by eating or consuming other organsisms; Primary consumers directly eat producers; Secondary consumers eat the primary consumer; Tertiary consumers eat the secondary consumer
What is a decomposer? - Give an example Organisms which break down energy in dead plants and animals releasing the minerals and elements stored within them: Examples include fungi and bacteria; Earthworms are detritivores
What is the difference between a food chain and a food web? Both describe the feeding relationships between organisms; Food chain shows one organism eating another Whilst food webs show the complex relationships between organisms
What is the principle source of energy in all ecosystems? The sun
Describe four ways energy is lost between the sun and the producer Approximately 90% of the sun's energy is reflected Not all wavelengths can be absorbed Light may not fall on the chlorophyll Photosynthetic limiting factors
Describe four ways energy is lost between the producer and the consumer Some of the organism isn't eaten Some part of the organism cannot be digested Energy lost in excretory materials Heat losses - to the environment or due to metabolic activity (respiration)
What is the equation for energy efficiency? Energy transfer = (energy available after the transfer) / (energy available before the transfer)
Give the equation for net production Net production = gross production - respiratory losses Gross production is the total quantity of energy that the plants in a community convert to organic matter
What are the drawbacks associated with a pyramid of number? No account taken for size Numbers can be so great it is impossible to represent them accurately
What are the advantages and disadvantages associated with a pyramid of biomass? Does take into account the size of an organisms But organisms must be dead
Why is a pyramid of energy often the best choice? More reliable Most accurate representation of energy flow
What are the units associated with energy in an energy pyramid? kJm^-2year^-1 kJ per metre squared per year
What is an agricultural ecosystem? Made up of domesticated animals and plants to produce food; Try to maximise energy from the sun transferred to humans
What is productivity, in relation to plants? Productivity is the rate at which something is produced Gross productivity is the rate at which plants assimilate energy from the sun into chemical energy Net productivity = gross productivity - respiratory loses
Give to additional sources of energy in an agricultural ecosystem Food the farmer eats in order to do work Fossil fuels used by machinary
What four things should a pesticide be? Be specific Bio-degrade Be cost effective Not accumalate
Describe biological control of pests: Aims to control pest numbers not eradicate them Pest control organism may become a pest itself Pests will not become resistant Once introduced will reproduce themselves
What does integrated pest control involve? Choosing a plant to suit the local area, Providing a habitat for natural predators, Regular monitoring, Removing pest mechanically, Use of biological agents, Using pesticides as a last resort
How is energy conserved when rearing livestock? Constricting movement, Keeping environment warm to reduce energy lost through thermoregulation, Controlling feeding so they receive the optimum amount of food, Excluding predators, Selective breeding to produce species that are efficient at converting food to biomass, Use of hormones to increase growth
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