Slides in this set
· An ecosystem is any group of living organisms and
non-living things occurring together.
· HABITAT: The place where an organism lives.
· POPULATION: All the organisms of a species that
live in the same place at the same time and can
· COMMUNITY: All the populations of different
species that live in the same place at the same time.
· The role that a certain species plays in an
ecosystem is called its NICHE.
· BIODIVERSITY: The range of different species with a
range of different alleles living in an environment…read more
· At each TROHPIC LEVEL of a food chain energy is
· This is because all the energy gained by one
organism is not put on as biomass for the next
organism to consume.
· A lot of the energy is lost through respiration,
movement, excretion, heat production etc.
· This why they are generally fewer organisms at
higher trophic levels of a food chain, as there is less
biomass to support them.…read more
· A pyramid of biomass is often drawn using the dry
mass of the organisms at each trophic level to show
how much energy is lost between trophic levels.
· However because some organisms release different
amounts of energy per kg than others a pyramid of
energy is sometimes used instead, as it is more
· Pyramids of energy are drawn using a calorimeter.
A sample of organisms at each level is collected and
burnt in the calorimeter. The energy released is
calculated by measuring the temperature rise in a
known mass of water.
· This is quite destructive and is quite a complicated
procedure so pyramids of biomass usually suffice.…read more
· PRODUCTIVITY is a measure of the rate of flow of
energy through each trophic level.
· It is measured in mega joules per meter squared per
· At the base of the food chain the productivity of
plants is called PRIMARY PRODUCTIVITY.
· The GROSS primary productivity is rate at which
light energy is converted into chemical energy via
· The NET primary productivity is the amount of
chemical energy that is actually available to
consumers as biomass, as some of the energy will
be lost via respiration and various other processes.…read more