UNIT 20: ORGANISM AND THEIR ENVIRONMENT
Sun is the principle source of energy input to biological systems
The flow of energy through living organisms including light energy from the sun
and chemical energy in organisms and its eventual transfer to the environment
The energy flows through biological system, used up by organisms involved or
released into the environment but never recycled
Food chain: showing the transfer of energy from one organism to the next,
beginning with a producer
Energy is transferred between organisms in a food chain by ingestion
Plants break down food by respiration for energy
Animals get their energy by ingesting plants or by eating animals which have
eaten plants
Trophic level: position of an organism in a food chain, food web, pyramid of
numbers or biomass
Energy is lost at each level through the process of respiration as heat
When an organism eats another, it rarely eats all of it so not all is transferred to
the organism
Not all molecules are digested and absorbed
Inefficient
Why food chains usually have fewer than 5 trophic levels
o On average, about 90% of the energy is lost at each level
o The further along the chain you go, the less energy there is
o Towards the end, the organisms get fewer in number
o The loss of energy along the chain limits the length of it
Consuming plants has a greater efficiency than feeding plants to livestock that
will be used as food because we acquire more energy ass less of it is loss
through trophic levels
Food web: a network of
interconnected food chains
Producer: an organism that
makes its own organic nutrients,
usually using energy from
sunlight through photosynthesis
Consumer: an organism that
gets its energy by feeing on other
organisms
, UNIT 20: ORGANISM AND THEIR ENVIRONMENT
Consumers may be classes as primary, secondary, tertiary according to position
in a food chain
Herbivore: an animal that gets its energy by eating plants
Carnivore: an animal that gets its energy by eating other animals
Decomposer: an organism that gets its energy form dead or waste material
Impacts humans have through over-harvesting of food species and through
introducing foreign species to a habitat
o Over harvesting causes the reduction in numbers of a species to the point
where it is endangered or made extinct, affecting the biodiversity
o Disrupt natural food chain of the habitat
o Risk of extinction of a species
Pyramid of biomass
Pyramid of numbers
Inverted pyramid of numbers
Advantage of using pyramid of
biomass
In a pyramid of numbers, 1 large
individual is shown in the same way as
one very tiny individual
Indicates energy available
Always pyramid shape and pyramid of
number is not always
Carbon cycle
Sun is the principle source of energy input to biological systems
The flow of energy through living organisms including light energy from the sun
and chemical energy in organisms and its eventual transfer to the environment
The energy flows through biological system, used up by organisms involved or
released into the environment but never recycled
Food chain: showing the transfer of energy from one organism to the next,
beginning with a producer
Energy is transferred between organisms in a food chain by ingestion
Plants break down food by respiration for energy
Animals get their energy by ingesting plants or by eating animals which have
eaten plants
Trophic level: position of an organism in a food chain, food web, pyramid of
numbers or biomass
Energy is lost at each level through the process of respiration as heat
When an organism eats another, it rarely eats all of it so not all is transferred to
the organism
Not all molecules are digested and absorbed
Inefficient
Why food chains usually have fewer than 5 trophic levels
o On average, about 90% of the energy is lost at each level
o The further along the chain you go, the less energy there is
o Towards the end, the organisms get fewer in number
o The loss of energy along the chain limits the length of it
Consuming plants has a greater efficiency than feeding plants to livestock that
will be used as food because we acquire more energy ass less of it is loss
through trophic levels
Food web: a network of
interconnected food chains
Producer: an organism that
makes its own organic nutrients,
usually using energy from
sunlight through photosynthesis
Consumer: an organism that
gets its energy by feeing on other
organisms
, UNIT 20: ORGANISM AND THEIR ENVIRONMENT
Consumers may be classes as primary, secondary, tertiary according to position
in a food chain
Herbivore: an animal that gets its energy by eating plants
Carnivore: an animal that gets its energy by eating other animals
Decomposer: an organism that gets its energy form dead or waste material
Impacts humans have through over-harvesting of food species and through
introducing foreign species to a habitat
o Over harvesting causes the reduction in numbers of a species to the point
where it is endangered or made extinct, affecting the biodiversity
o Disrupt natural food chain of the habitat
o Risk of extinction of a species
Pyramid of biomass
Pyramid of numbers
Inverted pyramid of numbers
Advantage of using pyramid of
biomass
In a pyramid of numbers, 1 large
individual is shown in the same way as
one very tiny individual
Indicates energy available
Always pyramid shape and pyramid of
number is not always
Carbon cycle
