This website works best with JavaScript switched on. Please enable JavaScript
- Centre Services
- Associate Extranet
- All About Maths
AS and A-level Biology
- Specification
- Planning resources
- Teaching resources
- Assessment resources
- Introduction
- Specification at a glance
- 3.1 Biological molecules
- 3.3 Organisms exchange substances with their environment
- 3.4 Genetic information, variation and relationships between organisms
3.5 Energy transfers in and between organisms (A-level only)
- 3.6 Organisms respond to changes in their internal and external environments (A-level only)
- 3.7 Genetics, populations, evolution and ecosystems (A-level only)
- 3.8 The control of gene expression (A-level only)
- Scheme of assessment
- General administration
- Mathematical requirements and exemplifications
- AS practical assessment
- A-level practical assessment
Life depends on continuous transfers of energy.
In photosynthesis, light is absorbed by chlorophyll and this is linked to the production of ATP.
In respiration, various substances are used as respiratory substrates. The hydrolysis of these respiratory substrates is linked to the production of ATP.
In both respiration and photosynthesis, ATP production occurs when protons diffuse down an electrochemical gradient through molecules of the enzyme ATP synthase, embedded in the membranes of cellular organelles.
The process of photosynthesis is common in all photoautotrophic organisms and the process of respiration is common in all organisms, providing indirect evidence for evolution.
In communities, the biological molecules produced by photosynthesis are consumed by other organisms, including animals, bacteria and fungi. Some of these are used as respiratory substrates by these consumers.
Photosynthesis and respiration are not 100% efficient. The transfer of biomass and its stored chemical energy in a community from one organism to a consumer is also not 100% efficient.
Photosynthesis (A-level only)
Content | Opportunities for skills development |
|---|---|
The light-dependent reaction in such detail as to show that: The light-independent reaction uses reduced NADP from the light-dependent reaction to form a simple sugar. The hydrolysis of ATP, also from the light-dependent reaction, provides the additional energy for this reaction. The light-independent reaction in such detail as to show that:
|
Students could devise and carry out experiments to investigate the effect of named environmental variables on the rate of photosynthesis using aquatic plants, algae or immobilised algal beads. |
Use of chromatography to investigate the pigments isolated from leaves of different plants, eg, leaves from shade-tolerant and shade-intolerant plants or leaves of different colours. Investigation into the effect of a named factor on the rate of dehydrogenase activity in extracts of chloroplasts. |
Respiration (A-level only)
Content | Opportunities for skills development |
|---|---|
Respiration produces ATP. Glycolysis is the first stage of anaerobic and aerobic respiration. It occurs in the cytoplasm and is an anaerobic process. Glycolysis involves the following stages: If respiration is only anaerobic, pyruvate can be converted to ethanol or lactate using reduced NAD. The oxidised NAD produced in this way can be used in further glycolysis. If respiration is aerobic, pyruvate from glycolysis enters the mitochondrial matrix by active transport. Aerobic respiration in such detail as to show that: |
Students could use a redox indicator to investigate dehydrogenase activity. |
Investigation into the effect of a named variable on the rate of respiration of cultures of single-celled organisms. |
|
Energy and ecosystems (A-level only)
Content | Opportunities for skills development |
|---|---|
In any ecosystem, plants synthesise organic compounds from atmospheric, or aquatic, carbon dioxide. Most of the sugars synthesised by plants are used by the plant as respiratory substrates. The rest are used to make other groups of biological molecules. These biological molecules form the biomass of the plants. Biomass can be measured in terms of mass of carbon or dry mass of tissue per given area. The chemical energy store in dry biomass can be estimated using calorimetry. Gross primary production ( ) is the chemical energy store in plant biomass, in a given area or volume. Net primary production ( ) is the chemical energy store in plant biomass after respiratory losses to the environment have been taken into account, ie where represents gross production and represents respiratory losses to the environment. This net primary production is available for plant growth and reproduction. It is also available to other trophic levels in the ecosystem, such as herbivores and decomposers. The net production of consumers ( ), such as animals, can be calculated as:
where represents the chemical energy store in ingested food, represents the chemical energy lost to the environment in faeces and urine and represents the respiratory losses to the environment. Primary and secondary productivity is the rate of primary or secondary production, respectively. It is measured as biomass in a given area in a given time eg kJ ha year . appreciate the ways in which production is affected by farming practices designed to increase the efficiency of energy transfer by: |
Students could be given data from which to calculate gross primary production and to derive the appropriate units.
Students could carry out investigations to find the dry mass of plant samples or the energy released by samples of plant biomass.
Students could be given data from which to calculate:
Students could be given data from which to calculate percentage yields. |
Nutrient cycles (A-level only)
Content | Opportunities for skills development |
|---|---|
Nutrients are recycled within natural ecosystems, exemplified by the nitrogen cycle and the phosphorus cycle. Microorganisms play a vital role in recycling chemical elements such as phosphorus and nitrogen. (The names of individual species of bacteria are required). The use of natural and artificial fertilisers to replace the nitrates and phosphates lost by harvesting plants and removing livestock. The environmental issues arising from the use of fertilisers including leaching and eutrophication. | Students could devise investigations into the effect of named minerals on plant growth. |
A-Level AQA Biology - Energy Transfers in Organisms
Finish sign up, energy transfers & nutrient cycles, energy transfers.
In any ecosystem, plants are the producers in a food web as they are able to produce their own carbohydrates using carbon dioxide in the atmosphere or water. Between each trophic level in a food web, the majority of the energy is lost due to respiration and excretion. The remaining energy is used to form the biomass.
The amount of biomass remaining in an organism can be measured in terms of mass of carbon or dry mass of tissue per given area. How productive an ecosystem is depends on the abiotic and biotic factors. Plenty of water, light, warmth, and green plants will maximize the rates of photosynthesis and therefore result in more carbohydrates being produced in the plants. This can be quantified using GPP and NPP. Gross primary production ( GPP ) is the chemical energy stored in plant biomass, in a given area or volume. It is the total energy resulting from photosynthesis. Net primary production ( NPP ) is the chemical energy stored in plant biomass taking into account the energy that will be lost due to respiration (R).
NPP = GPP – R
The NPP is the energy left over that is available to the plant to create new biomass and therefore available to the next trophic level in a food web. To work out the net production of consumers (N), such as animals, the formula below can be used:
N = I – F + R
I = the chemical energy stored in ingested food F = the chemical energy lost to the environment in faeces and urine R = respiratory losses.
Rates of productivity are recorded using the units kJ ha–1 year–1. kJ is the unit for energy, but these units also include per unit area and per year. It is recorded as per unit area to standardize the results to enable environments to be compared- it takes into account that different environments will vary in size. The units are also per year to take into account the impact seasons will have on rain, light, and heat – it provides an annual average to allow fair comparisons between environments.
Nutrient Cycles
Nutrients are recycled within natural ecosystems, exemplified by the nitrogen cycle and the phosphorus cycle. Mycorrhizae play an important role in nutrient cycle. Mycorrhizae are fungal associations between plant roots and beneficial fungi. As a result, the fungi entwined around the plant roots provide a larger surface area for water and mineral absorption. The fungi part of the mycorrhizae acts like a sponge and can absorb and hold onto water and minerals surrounding the root. This is of benefit to the plant, as in times of drought the mycorrhizae store of water and minerals can be used. This is a mutualistic relationship because the plant provides the fungi with carbohydrates.
Nitrogen Cycle
Nitrogen is an important element that is needed to create amino acids/proteins, DNA, RNA, and ATP. The cycle is split into four key processes: nitrogen-fixation, nitrification, denitrification, and ammonification.
Nitrogen-fixation
Nitrogen-fixing bacteria are able to break the double bond between the two nitrogen atoms in nitrogen gas in the atmosphere and fix this nitrogen into ammonium ions. The bacteria are either free-living in the soil or it is symbiotic (mutualistic relationship), living in the root nodules of plants. This is common in leguminous plants such as clover and beans.
Nitrification
The ammonium ions in the soil are converted to nitrite and then nitrate ions in the soil by nitrifying bacteria. This is a two-stage oxidation reaction.
Denitrification
This stage is not useful as it returns the nitrogen in compounds back to nitrogen gas in the atmosphere, so it cannot be absorbed by plants. Anaerobic denitrifying bacteria do this.
Ammonification
Proteins, urea, and DNA can be decomposed in dead matter and waste by saprobionts. These are bacteria and fungi that can digest waste extracellularly, this is saprobiotic nutrition, and returns ammonium ions into the soil.
Phosphorus Cycle
Phosphorus is an essential element for life as it is needed to create DNA, RNA, ATP, and phospholipid bilayers. The phosphorus cycle is different from the carbon (not on the specification) and nitrogen cycle because phosphorus is not found as a gas in the atmosphere. Instead, the main store is in sedimentary rocks.
Fertilisers
Fertilisers are added to soil to replace the nutrients lost nitrate and phosphate ions when plants are harvested and removed from the cycle as crops. These fertilisers can be either natural (manure) or artificial fertilisers (inorganic chemicals).
Natural fertilisers are cheaper and often free if the farmer owns animals. However, the exact minerals and proportions cannot be controlled.
Artificial fertilisers are chemicals created to contain exact proportions of minerals. Inorganic substances are more water-soluble, and therefore more of these ions dissolve in the water surrounding the soil. Whilst this is an advantage to the plant for absorbing the nitrates and phosphates, the downside is that their high solubility means that larger quantities are washed away with rainfall and therefore have a greater impact on the environment.
Leaching is when water-soluble compounds are washed away, often into rivers or ponds. If nitrogen fertilisers leach into waterways it causes eutrophication.
Eutrophication is when nitrates leached from fertilised fields stimulate the growth of algae in a pond. The excessive growth of algae creates a blanket on the surface of the water which blocks out light. As a result, plants below cannot photosynthesize and die. Bacteria within the water feed and respire on the dead plant matter. This results in an increase in bacteria, which are all respiring and using up the oxygen within the water. Eventually, fish and other aquatic organisms die due to the lack of dissolved oxygen in the water.
Energy Transfer in Ecosystems
- Understand the concept of biomass and its transfer in food chains.
- Suggest and explain why only a small amount of biomass is transferred to the subsequent trophic level.
- Understand how this limits the number in a food chain.
- Calculate Gross Primary Productivity (GPP) and Net Primary Productivity (NPP) from provided data.
- Evaluate the above-mentioned data effectively.
- Be prepared to calculate the net production of consumers or percentage yield.
- Practice all biomass related calculations.
- Understand the difference between primary and secondary productivity.
- In case of practical scenarios where biomass has been calculated, be sure to understand the methodology used.
A Level Biology
Instant Access to A Level Biology Revision
Sign up now to get access to the entire library of a level biology resources for all exam boards.
If you're ready to pass your AQA A-Level Biology exams, become a member now to get complete access to our entire library of revision materials.
Join over 22,000 learners who have passed their exams thanks to us!
Or try a sample...
Not ready to purchase the revision kit yet? No problem. If you want to see what we offer before purchasing, we have a free membership with sample revision materials.
Signup as a free member below and you'll be brought back to this page to try the sample materials before you buy.
3.5 Energy transfers in organisms
- Life depends on continuous transfers of energy.
- In photosynthesis, light is absorbed by chlorophyll and this is linked to the production of ATP.
- In respiration, various substances are used as respiratory substrates. The hydrolysis of these respiratory substrates is linked to the production of ATP.
- In both respiration and photosynthesis, ATP production occurs when protons diffuse down an electrochemical gradient through molecules of the enzyme ATP synthase, embedded in the membranes of cellular organelles.
- The process of photosynthesis is common in all photoautotrophic organisms and the process of respiration is common in all organisms, providing indirect evidence for evolution.
- In communities, the biological molecules produced by photosynthesis are consumed by other organisms, including animals, bacteria and fungi. Some of these are used as respiratory substrates by these consumers.
- Photosynthesis and respiration are not 100% efficient. The transfer of biomass and its stored chemical energy in a community from one organism to a consumer is also not 100% efficient.
Source: AQA Spec
Included in this download
| Module | Title |
|---|---|
| 3.5.1 | Photosynthesis |
| 3.5.2 | Respiration |
| 3.5.3 | Energy and ecosystems |
| 3.5.4 | Nutrient cycles |
- International
- Education Jobs
- Schools directory
- Resources Education Jobs Schools directory News Search
A-Level Biology Revision Guide Topic 5 Energy Transfers
Subject: Biology
Age range: 16+
Resource type: Assessment and revision
Last updated
24 August 2024
- Share through email
- Share through twitter
- Share through linkedin
- Share through facebook
- Share through pinterest
This is an extremely useful resource for A Level Biology students who want to achieve top marks in their exams. This revision guide contains all the essential knowledge and key words you need to achieve an A* in your exams. Its condensed and is put into an easy to understand format.
Tes paid licence How can I reuse this?
Get this resource as part of a bundle and save up to 43%
A bundle is a package of resources grouped together to teach a particular topic, or a series of lessons, in one place.
A-Level AQA Revision Guide Bundle (ALL UNITS 1-8)
This is an extremely useful resource for A Level Biology students who want to achieve top marks in their exams. This revision guide contains all the essential knowledge and key words you need to achieve an A* in your exams. Its condensed and is put into an easy to understand format. This resource is cheaper to buy as a bundle rather than individually. It contains all the specification needed for an A*
Your rating is required to reflect your happiness.
It's good to leave some feedback.
Something went wrong, please try again later.
This resource hasn't been reviewed yet
To ensure quality for our reviews, only customers who have purchased this resource can review it
Report this resource to let us know if it violates our terms and conditions. Our customer service team will review your report and will be in touch.
Not quite what you were looking for? Search by keyword to find the right resource:
Efficiency of Energy Transfers ( OCR A Level Biology )
Revision note.
Efficiency of Energy Transfers
- Light falls away from plants
- Light passes through leaves or is reflected away
- Light is a mixture of wavelengths, and only certain wavelengths stimulate photosynthesis
- During photosynthesis, primary producers such as plants and algae convert light energy to chemical energy in biological molecules
- The storing of this chemical energy as plant biomass makes a certain amount of energy available to the next trophic level, the primary consumers
- Not all the plant's biomass is eaten by the primary consumer
- Think about the energy content of cow dung, which can be dried and used as a heating/cooking fuel, as it contains a lot of undigested biomass e.g. cellulose
- The primary consumer converts a lot of chemical energy to movement and heat , and only a small amount to new biomass in its own body
- The efficiency of biomass transfer from one trophic level to the next is low , typically around 10%
Calculating efficiency of biomass transfers between trophic levels
- Given the appropriate data, it is possible to calculate the efficiency of biomass transfer from one trophic level to the next, as a percentag e
- Biomass transferred = biomass that has passed to the higher trophic level
- Biomass intake = biomass of the lower trophic level that has been consumed
Worked example
A blackberry bush with a mass of 35 kg is fed upon by aphids with a collective mass of 4.1 kg. Calculate the percentage efficiency of energy transfer in this step of the food chain.
Step 1: Ensure both units are the same
In this case, both are expressed in kg so the units do not need to be converted
Step 2: Substitute the values into the formula
Calculating the efficiency of energy transfer between trophic levels
- A common way of working out the efficiency of energy transfer is calculating the net productivity of one trophic level as a percentage of the net productivity of the preceding trophic level
Net productivity of producers
- The net productivity of producers (also known as net primary productivity or NPP) can be calculated using the following equation:
NPP = GPP - R
- GPP = gross primary productivity
- R = respiratory losses
Net productivity of consumers
- The net productivity of consumers can be calculated using the following equation:
N = I - (F + R)
- I = the chemical energy store in ingested food
- F = the chemical energy lost to the environment in faeces and urine
- R = the respiratory losses to the environment
A wheat farmer decides to use biological control against insect pests that are eating her wheat crop. The farmer introduces a species of toad. By eating the insect pests, the toads ingest 10,000 kJ m -2 yr -1 of energy but lose 2,000 kJ m -2 yr -1 of this energy in faeces and urine. They lose a further 7,000 kJ m -2 yr -1 using energy for respiration. Calculate the percentage efficiency of energy transfer from the insects to the toads.
Step 1: Calculate the net productivity of the toads
N = 10,000 - (2,000 + 7,000)
N = 10,000 - 9,000
N = 1,000 kJ m -2 yr -1
Step 2: Write out the equation for % efficiency and substitute in the known values
% Efficiency = (1,000 ÷ 10,000) × 100
Step 3: Calculate the efficiency
% Efficiency = (0.1) × 100
% Efficiency = 10%
How human activities can manipulate the transfer of biomass through ecosystems
- Human activity can adjust the efficiency of transfer of biomass between trophic levels, usually to maximise it in the context of maximising agricultural productivity
- Providing artificial light in greenhouses on overcast days
- Optimising planting distances between crops
- Irrigation to maximise growth in dry weather
- Use of fertilisers
- Selective breeding for fast growth
- Use of fungicides/pesticides
- Fencing to exclude grazers
- Ploughing and herbicides to kill weeds
- Plant crops that store energy in edible form e.g. seeds, fruit, tubers
- Use of good quality feeds / food supplements
- Use antibiotics and vaccines to reduce disease
- Control predation with fencing or with indoor animal husbandry
- Reduce competition for grazing e.g. rabbits, deer
- Indoor husbandry to reduce energy loss from movement or from getting cold outside
Human activity can increase the efficiency of biomass transfer in an arable farm setting
Exam questions can refer to biomass and energy interchangeably. Remember, the biomass of an organism is effectively a measure of how much chemical energy is stored within it!
You've read 0 of your 10 free revision notes
Get unlimited access.
to absolutely everything:
- Downloadable PDFs
- Unlimited Revision Notes
- Topic Questions
- Past Papers
- Model Answers
- Videos (Maths and Science)
Join the 100,000 + Students that ❤️ Save My Exams
the (exam) results speak for themselves:
Did this page help you?
Author: Phil
Phil has a BSc in Biochemistry from the University of Birmingham, followed by an MBA from Manchester Business School. He has 15 years of teaching and tutoring experience, teaching Biology in schools before becoming director of a growing tuition agency. He has also examined Biology for one of the leading UK exam boards. Phil has a particular passion for empowering students to overcome their fear of numbers in a scientific context.
This discussion is now closed.
- AQA A-Level Biology Paper 3 [21st June 2023] Exam Chat
- AQA A-level biology essay topics
- GCSE Physics Question Help
- Elastic collision and conservation of momentum
- Energy dissipated
- calculate the total thermal energy
- Biology a level question - photosynthesis
- GCSE physics power help
- Hard Enthalpy Change Question - Help Needed
- AQA A-Level Biology Paper 3 (7402/3) - 19th June 2024 [Exam Chat]
- A level physics question
- igcse Edexcel physics 2024 regional
- Transferring uni with bad a levels
- Illustrations in essays?
- Edexcel IGCSE Physics Paper 2 (4PH1/2P-2PR) - 14th June 2024 [Exam Chat]
- Biology - glycolysis
- A level physics Electricity question (5)
- How can 2 waves be in phase if they have different amplitudes?
- How do u know if u need to use mass of water or alcohol - enthalpy change a level
- Transfer application
Energy Transfer Essay
Related discussions
Last reply 2 days ago
Last reply 3 days ago
Last reply 5 days ago
Last reply 2 weeks ago
Posted 2 weeks ago
Posted 3 weeks ago
Last reply 3 weeks ago
Posted 1 month ago
Last reply 1 month ago
Posted 2 months ago
Last reply 2 months ago
Last reply 3 months ago
Articles for you
Student survival guide: electricity and gas bills
Finding a university place in Ucas Clearing 2024: 10 top tips to help you get ready
Top 10 tips for Ucas Clearing 2024
Bringing business people into the classroom: what students learn from industry professionals
IMAGES
COMMENTS
Thermoregulation is a major source of energy loss and transfer to the surroundings in warm blooded animals. Sixth Paragraph. Serves the animals metabolic demands, which include cellular metabolism and regulation of body heat in endotherms. Energy required for metabolic maintenance in respiration, which is deducted from gross productivity to ...
A collection of high mark, sample essays for A-Level Biology, providing helpful revision content and examples of logical structuring. New Specification! Includes essays on the titles: - The Importance of movement in living organisms - Explain the importance of shapes fitting together in cells and organisms - Carbon dioxide may affect organisms ...
Biology is detailed and comprehensive A-level content, uses appropriate terminology, and is very well written and always clearly explained. No significant errors or irrelevant material. For top marks in the band, the answer shows evidence of reading beyond specification requirements. 16-20. Relational.
The importance of shapes fitting together in cells and organisms. 1) Enzyme properties and digestion. 2) Protein structure. 3) Plasma membrane structure and cell transport. 4) Antigens, antibodies, B cells & T cells. 5) Vaccines. 6) Structure of DNA. 7) DNA Replication (not PCR) 8) Transcription & translation.
The Need for Energy. Living organisms are composed of cells, and within each cell, many activities and processes are constantly being carried out to maintain life. Work in a living organism requires energy and usable carbon compounds. Essential work within organisms table. As the metal ions are both moving against their concentration gradient ...
How energy is transferred within and between organisms. 2013. 10 a. The membranes of different types of cells are involved in many different functions. 2013. 10 b. There are many different types of relationships and interactions between organisms. 2012. 10 a.
3.5 Energy transfers in and between organisms (A-level only) Life depends on continuous transfers of energy. In photosynthesis, light is absorbed by chlorophyll and this is linked to the production of ATP. In respiration, various substances are used as respiratory substrates. The hydrolysis of these respiratory substrates is linked to the ...
I want to help you achieve the grades you (and I) know you are capable of; these grades are the stepping stone to your future. Even if you don't want to stud...
Trophic levels describe the position of an organism in a food chain, web or pyramid. Trophic levels can be represented by numbers or by the name of that trophic level e.g. plants and algae are in trophic level 1, otherwise known as producers. Further trophic levels are numbered subsequently according to how far the organism is along the food chain.
44 essay titles and indiciative mark schemes for AQA A level biology Paper 3 25 mark essay question. contents essay mark schemes general guidance. Skip to document. University; High School. Books; Discovery. ... The transfer of energy between different organisms and between these organisms and their environment.
Energy Transfers. In any ecosystem, plants are the producers in a food web as they are able to produce their own carbohydrates using carbon dioxide in the atmosphere or water. Between each trophic level in a food web, the majority of the energy is lost due to respiration and excretion. The remaining energy is used to form the biomass.
Exam-specific revision content for every subject. Unlimited past paper questions on every topic. Personalised, examiner feedback on your answers. Try Adapt Assessment today →. Everything you need to know about Energy Transfer in Ecosystems for the A Level Biology AQA exam, totally free, with assessment questions, text & videos.
Biology Essay 1 --How Energy is Transferred Within and Between Organisms - Free download as Word Doc (.doc / .docx), PDF File (.pdf), Text File (.txt) or read online for free. 1) The sun provides energy for photosynthesis, which captures this energy in plants through the process of chlorophyll absorbing photons and transferring electrons. 2) This captured energy is used to produce ATP and ...
Topic 5 - Energy Transfers in and Between Organisms. Acetyl coenzyme A: A two-carbon molecule formed in the link reaction when acetate reacts with coenzyme A. It is oxidised in the Krebs cycle. Adenosine triphosphate (ATP): Universal energy carrier found in all living cells. Aerobic respiration: A form of cellular respiration that takes place ...
3.5 Energy transfers in organisms. Life depends on continuous transfers of energy. In photosynthesis, light is absorbed by chlorophyll and this is linked to the production of ATP. In respiration, various substances are used as respiratory substrates. The hydrolysis of these respiratory substrates is linked to the production of ATP.
energy transfer can be food chains and trophic levels, transfer of substances across membranes, active immunity, successions, ... AQA A-Level Biology Paper 3 [21st June 2023] Exam Chat ... AQA A-level biology essay topics; Alevel bio synoptic essay; Help my Eng Lang answer; Essay help - CIE IGCSE English Literature; AQA A-Level Biology Paper 3 ...
This is an extremely useful resource for A Level Biology students who want to achieve top marks in their exams. This revision guide contains all the essential knowledge and key words you need to achieve an A* in your exams. Its condensed and is put into an easy to understand format.
By eating the insect pests, the toads ingest 10,000 kJ m-2 yr-1 of energy but lose 2,000 kJ m-2 yr-1 of this energy in faeces and urine. They lose a further 7,000 kJ m-2 y r-1 using energy for respiration. Using the information above, calculate the net production of the toads and the percentage efficiency of energy transfer from the insects to ...
In stable communities, the processes that remove nutrients (e.g. plant growth) are balanced by the processes that return these nutrients (e.g. decomposition of dead plants and animals) This means these nutrients are constantly being cycled in ecosystems. Two examples of these nutrient cycles are: The nitrogen cycle. The phosphorous cycle.
Q-Chat. Phosphate ions are transferred through the food chain as animals eat the plants and animals eat them animals. When plants and animals die, saprobionts break down organic compounds, releasing phosphate ions into the soil for assimilation by plants. Weathering rocks also releases phosphate ions into the seas, lakes and rivers.
Calculate the percentage efficiency of energy transfer from the insects to the toads. Step 1: Calculate the net productivity of the toads. N = I - (F + R) N = 10,000 - (2,000 + 7,000) N = 10,000 - 9,000. N = 1,000 kJ m -2 yr -1. Step 2: Write out the equation for % efficiency and substitute in the known values.
AQA A-level biology essay topics; GCSE Physics Question Help; Elastic collision and conservation of momentum; Energy dissipated; Biology a level question - photosynthesis; calculate the total thermal energy; GCSE physics power help; Hard Enthalpy Change Question - Help Needed; AQA A-Level Biology Paper 3 (7402/3) - 19th June 2024 [Exam Chat]