Energy In Ecosystems Flashcards
What are consumers ?
Animals and fungi that cannot produce food from sunlight therefore they must eat other animals and plants for energy to live
What do herbivores eat ?
Only plant materials (e.g. Sheep)
What do carnivores eat ?
Only animal materials (e.g. Dog )
What do omnivores eat ?
Mixture of plant and animal materials (e.g. Man)
What do arrows in a food chain indicate ?
The direction of energy flow
How much energy is lost at each stage in a food chain and how much energy is passed on?
90% lost
10% passed on
How can energy be lost (3)
Movement
Heat
Undigested food
What can be said about short food chains ?
More efficient
What can we say about the greater the number of links ?
Less energy is passed on at each stage
What is a pyramid of numbers ?
A diagram that shows the number of organisms at each level in a food chain
What 2 trends do we see as we move up the pyramid ?
Number of organisms decreases
Size of organisms increases
What does a pyramid of biomass show?
The total mass of all the organisms at each stage in a food chain
What is the biomass at each level dependent on ?
The energy passed on at each stage in the food chain and can vary throughout the year
What is a pyramid of energy based on?
Productivity
How is a pyramid of energy measured as?
Grams of dry mass per metre squarer per year and then is converted into energy equivalent in kJ per metre squared per year (kJ/m2/year)
What is a pyramid of energy ?
A diagram that shows the amount of energy available at each level in a food chain
What are producers ?
Green plants which produce their own food by changing the sun’s light energy into chemical energy by photosynthesis
Why is nitrogen an essential element ?
Used to make DNA , amino acids and proteins
What percentage of the air is nitrogen ?
80%
What form do green plants absorb nitrogen ?
Nitrates from the soil and use it to make proteins
What is the nitrogen cycle is essential to provide ?
Nitrates for plants to absorb and use
What does the nitrogen cycle ensure ?
A continuous supply of nitrogen for years to come
What does nitrogen fixing bacteria do?
Convert nitrogen gas to nitrate
Can be found in root nodules of clover plant s
What do decomposers do ?
Convert protein to ammonium compounds
What do nitrifying bacteria do ?
Some convert ammonium compounds to nitrites and some convert nitrites to nitrates
What do denitrifying bacteria do?
Convert useful nitrates to nitrogen gas
What is competition ?
When 2 or more organisms require the same resource.
All living things need natural resources but there is not enough for everyone.
What is interspecific competition ?
Occurs when individuals of different species in an ecosystem require similar resources
What is intraspecific competition ?
Occurs between members of the same species. It can be very intense because the requirements of all individuals are identical
Where do we find the nitrogen fixing bacteria ?
Nitrogen fixing bacteria LIVE in legume root nodules
What is a food chain?
A diagram that shows the feeding relationships of organisms living together in a particular ecosystem
Describe how else nitrogen fixations can take place (natural event)
Lightning converts atmospheric nitrogen to nitrate. This nitrate is then dissolved in rain, falls to the ground and enters the soil
