Unit 3.4.5 - Energy Transfer Flashcards
What is an ecosystem?
All the organisms living in a particular area and all the abiotic conditions.
What is the main route by which energy enters an ecosystem?
Photosynthesis
How is energy transferred through the living organisms of an ecosystem?
When they eat each other.
What two diagrams show how energy is transferred through an ecosystem?
Food chains and food webs.
Why is there very rarely quaternary consumers?
Because the is so much energy lost between trophic levels there wouldn’t be enough energy in tertiary consumers for quaternary consumers to survive.
What does autotroph mean?
It is when something produces their own food.
What in the food chains are autotrophs?
Producers
What does heterotroph mean?
It when something gets their food from other organisms.
What in the food chains are heterotrophs?
Consumers
Usually what percentage of energy is passed on to the next trophic level?
10%
Is energy lost through growth of an organism and why?
No, because the energy still remains in the organism as biomass.
Give three reasons why energy is lost between light and the producer
- Not all light hits the plants. 2. Light might not hit a chlorophyll. 3. Light can be of the wrong wave length.
Give five reasons why energy is lost between the producer and the primary consumer.
- Not all plant material is eaten (roots) 2. Some plant material isn’t digested (cellulose) 3. Some energy is used by the plants (active transport) 4. Energy is lost through respiration 5. Some tissues like leaves die and decompose by decomposers.
Give seven reasons why energy is lost between the consumers.
- Not all the animal is eaten (bones) 2. Not all the animal material is digested 3. Some materials/energy is excreted in urine and faeces. 4. Energy is lost by maintaining a constant body temperature. 5. Energy is lost through respiration. 6. Some tissues die and are decomposed by decomposers. 7. Energy is lost through movement (respiration)
What formula can you use to calculate the efficiency of energy transfer?
How does the efficiency of energy transfer change as you move through the food chain?
It increases.
Why is energy transfer the least efficient from the sun to the producer?
So much energy is lost as it cannot be absorbed.
How does the efficiency of energy transfer differ from producer to consumer than from consumer to consumer?
Less efficient from the producer to consumer.
Why is energy transfer less efficient from producer to consumer than from consumer to consumer?
Plants contain a greater proportion of indigestible materials than animals.
How does the efficiency of energy transfer differ from warm blooded organisms to cold blooded organisms?
Less efficient in warm blooded organisms.
Why is energy transfer less efficient in warm blooded organisms than cold blooded organisms?
Warm blooded organisms use a lot of energy from respiration to keep their body temperature constant.
What do pyramid of numbers represent?
The relative number of organisms in an ecosystem at a given moment irrespective of biomass.
What are the three types of pyramids you can use to represent food chains?
- Pyramids of numbers 2. Pyramids of biomass 3. Pyramids of energy
What are the units for pyramids of numbers.
the number m-2y-1
Why are pyramids of numbers not always pyramid shaped?
One producer could sustain a lot of primary consumers (tree).
What do pyramids of biomass represent?
Relative biomass of organisms in an ecosystem at a given moment irrespective of numbers.
What is biomass?
The amount of organic material in an organism.
What is the units for pyramids of biomass?
kg m-2y-1
Why are pyramids of biomass usually pyramid shaped
Because biomass/energy is lost at each trophic level.
Why could a pyramid of biomass not be pyramid shaped?
If at a given moment the mass of the producers are very low.
Give an example when a pyramid of biomass is not pyramid shaped.
A whale going through and eating loads of plankton.
What do pyramids of energy represent?
The amount of energy transferred to each trophic level at a given moment irrespective of numbers of biomass.
Why are pyramids of energy always pyramid shaped?
Energy is always lost and cannot be created.
What are the units for pyramids of energy?
J m-2y-1
What is gross productivity?
The energy transferred to the next trophic level
What are the units for gross productivity?
J mass-1 area-1 time-1
What is respiratory loss?
The energy lost at a trophic level due to respiration
Why doesn’t all energy transferred become biomass in that organism?
Energy is lost through respiration
What is net productivity?
The amount of energy that’s available to the next trophic level
What formula is there for net productivity?
Net productivity = Gross productivity - Respiratory loss
What is intensive farming?
Changing an ecosystem by controlling the biotic and abiotic conditions to make it more favourable for crops and livestock
What is the aim of intensive farming?
Maximise net production by maximising gross production and minimising respiratory loss
What are the three general ways intensive farming can increase productivity?
- Increase the efficient of energy transfer 2. Remove growth limiting factors 3. Increase energy input
What is crop rotation?
Changing what you grow on each field periodically, rotating them around
What are the three ways crop rotation can help you increase crop yields?
- You can get crops with nitrogen fixing bacteria - legumes - to add more nitrogen to the soil 2. Different crops use different nutrients/ions from the soil 3. Different crops have different pest species
What are the three main intensive farming methods?
- Killing pest species 2. Using fertiliser 3. Rearing livestock intensively
What are three ways you can rear livestock intensively?
- Keep the animals in indoor pens 2. Give them special food 3. Slaughter them before they reach adult hood
Why are animals kept in indoor pens during rearing livestock intensively?
It keeps them warm to reduce heat loss and it reduces movement to reduce the respiratory loss
Why are animals given special food during rearing livestock intensively?
The food is high in energy and has less indigestible material in it, this increases the gross productivity
Why are animals slaughtered before them reach adult hood during rearing livestock intensively?
Before they reach adult hood they are still actively growing, young animals use a greater amount of their energy for growth so this means more of their energy is transferred to biomass.
What are three ethical issues with rearing livestock intensively?
- It can cause the animal pain 2. It can cause the animal distress 3. It restricts their natural behaviour
What are the three types of pesticides?
Insecticides, herbicides and fungicides
Why are herbicides used?
To kill weeds to trade the competition so the crop receives more energy so it can grow faster and larger increasing the gross productivity
Why are insecticides used?
To kill insects that would otherwise kill and damage the crop, they also reduce the biomass of the crop
Why are fungicides used?
To kill funguses that would otherwise kill and damage the crop, they also reduce the biomass of the crop
What are three environmental issue with using pesticides?
- It can cause bioaccumulation 2. It can directly affect other non pest species like butterflies 3. It can also indirectly affect other species, like if they were too each a lot of primary consumers that had small bits of the chemical inside of them
Other than using pesticides what is another way to kill pest species?
Biological agent
What is meant by adding a biological agent to kill pest species?
To introduce natural predators, parasites or pathogens to kill the pest
What is an integrated system?
Something that uses both chemical pesticides and biological agents to keep the pest levels below economic injury not eradicating them
Why can integrated systems decrease the overall cost?
If one method is particularly expensive it will save you money
Why are fertilisers used in intensive farming?
To stop minerals from being the limiting growth factor
What are four things fertilisers might contain? And why?
- Nitrate ions - amino acids 2. Phosphate ions - NADPH 3. Phospholipids - flowering 4. Potassium - flowering
What are the two types of fertiliser called?
Natural and artificial
What are natural fertilisers also called?
Organic fertilisers
What are artificial fertilisers also called?
Inorganic fertilisers
Where do natural fertilisers come from?
Animals - manure
What are artificial fertilisers?
Chemicals which contain lots of nitrate, phosphate or potassium ions
What is the difference between how fast natural and artificial fertiliser release their ions? And why?
Natural - slow release as needs to be decomposed Artificial - quick release as highly soluble
Do natural or artificial fertilisers contain more ions?
Artificial
What is an advantage of natural fertilisers?
Improves structure of soil giving good drainage and aeration
Other than quick release and containing more ions what are two advantages of artificial fertilisers?
Easy to store, easy to apply in precise amounts
What can fertilisers cause to water supplies?
Eutrophication
Why do you have to apply the right amount go fertiliser?
Too little and productivity won’t be increase, so less money can be made from selling the crop Too much and money is wasted as excess fertiliser is washed away
