Energy and Ecosystems Flashcards
Define the term ‘food chain’
Shows the feeding relationship between producers and consumers
Define the term ‘food web’
More accurate demonstration of feeding relationships. Links food webs of one habitat together.
Define the term ‘producers’
Photosynthetic organisms that produce organic substances using light energy, water , CO2 and mineral ions
Define the term ‘primary consumer’
Organism in the food chain that directly obtains its energy by feeding on the producer. The first consumer/ animal in the food chain
Define the term ‘secondary consumer’
Second consumer in the food chain. Feeds on the primary consumer
Define the term ‘tertiary consumer’
Third consumer in the food chain. Feeds on the secondary consumer
Define the term ‘trophic level’
Position in the food chain occupied by a producer or consumer
Define the term ‘herbivore’
Plant eating consumer
Define the term ‘carnivore’
Meat eating consumer
Define the term ‘omnivore’
Consumer that eats both plants and animals
Define the term ‘habitat’
The place where an organism normally lives and which is characterised by physical conditions and the other types of organism present
Define the term ‘ecosystem’
All the biotic and abiotic components of a particular area
Define the term ‘biomass’
The total mass of living material, normally measured in a specific area over a time period
Explain how plants synthesise organic compounds
-Photosynthesis
-Using CO2 from the atmosphere or dissolved in water and solar energy
-To make glucose
State three ways in which the sugars produced in photosynthesis are used
-Respiration
-To release energy for growth
-To make biological molecules such as cellulose
State how biomass is measured
The dry mass of tissue per unit area
State the method that is used to measure the total chemical energy store in dry biomass
Calorimetry
Describe the method to measure biomass
- Dry mass is weighed
- Water tank with a known volume of water at 400oC
- Dry mass is burnt in a chamber with pure oxygen
- Measure the temperature change of the water
- Energy released= chemical energy stored in dry biomass ( j or Kj )
Define the term ‘Gross Primary Production (GPP)’
The chemical energy store in plant biomass in a given area or volume
Define the term ‘Net Primary Production (NPP)’
The chemical energy store in plant biomass taking into account respiratory losses to the environment
State the equation to calculate ‘Net Primary Production (NPP)’
NPP= GPP - R
What is NPP?
-Energy available to the plant for growth and reproduction
-Energy available to organisms in the next trophic level (including herbivores and decomposers)
State the equation to calculate the net production of consumers
N = I - ( F + R )
N= Net production
I= chemical energy in ingested food
F= chemical energy lost in faeces and urine
R= energy lost in respiration
State six methods used by farmers to increase energy transfers
-Using chemical pesticides e.g. insecticides and herbicides
-Reducing species diversity through monoculture
-Maximising solar input
-Limiting movement
-Heating the environment
-Protein/ supplement rich diet
Explain how using chemical pesticides e.g. insecticides and herbicides increases the efficiency of energy transfers and state two challenges of this farming method
-Increased photosynthesis = increased biomass = increased NPP
Challenges:
-Eutrophication / pollution
-Reduces species diversity
Explain how reducing species diversity through monoculture (growth of one species) increases the efficiency of energy transfers and state two challenges of this farming method
-Reduces competition = higher yield of desired crop = more profit
Challenges:
-Reduces diversity which decreases stability
-Drains nutrients from the soil
Explain how maximising solar input increases the efficiency of energy transfers and state two challenges of this farming method
-Increases initial energy input = increases GPP = increase in NPP
Challenges:
-Costly -> energy intensive
-Light pollution
Explain how limiting movement increases the efficiency of energy transfers and state three challenges of this farming method
-Reduces respiratory losses = more energy to tissues
Challenges:
-Unethical
-Spread of diseases
-Antibiotic resistance (to reduce risk of spread of disease which would occur very quickly but as these are given often it leads to antibiotic resistance)
Explain how heating the environment increases the efficiency of energy transfers and state two challenges of this farming method
-Reduces losses for temperature control = optimal for growth
Challenges:
-Costly
-Pollution
Explain how providing a protein rich/ supplement rich diet increases the efficiency of energy transfers and state two challenges of this farming method
-Increases biomass = increases profits
Challenges:
-Unethical (artificial)
-Costly
State three reasons for the low efficiency of energy transfer from secondary consumers to tertiary consumers in an ecosystem
-Not all of organism is eaten or digested e.g. bone
-Some is lost to respiratory losses or as heat lost through movement
-Some is lost in excretory processes
State two reasons why in natural ecosystems most of the light falling on producers is not used in photosynthesis
-Not all wavelengths of light can be absorbed an utilised
-Doesn’t have the correct chlorophyll
-The light misses the chlorophyll
-Other limiting factors
State the equation to calculate efficiency
Efficiency= energy available after the transfer / energy available before the transfer x100
In natural ecosystems, the efficiency of energy transfers is low. State three reasons why.
-Only energy source is the sun (only 1-3% of light energy absorbed by chlorophyll)
-High species diversity= competition
-There is a natural climax community
-Loss of energy to the surroundings
-Recycling of nutrients in the environment -> decomposes utilise some energy as well so there is less available for the consumers
Explain why farming cattle is less efficient than farming crops due to energy transfer
-Simpler food chain (crop= just producer , cattle= producer then cattle)
-Energy lost between tropic levels
-Energy lost via respiration
