Ecosystems Flashcards
Outline the levels of organisation in an ecosystem
● Individual
● Population
● Community
● Ecosystem
Define population
All organisms of the same species living
with one another in a habitat
Define community
All of the populations of different species
living together in a habitat
Define ecosystem
The community of organisms and
non-living components of an area and
their interactions
Organisms within a community are described as
being ‘interdependent’. What does this mean?
● Organisms are dependent upon each other.
● Achange in the population of one species can
affect other populations within a community
Give some examples of interdependence in a
community
● Plants depend on pollinators e.g. bees
● Herbivores are dependent on plants
● Animals are dependent on mates
Describe mutualism
The interaction between two organisms
where both benefit as a result of their
relationship
Describe parasitism
The interaction between two organisms
where only one organism, the parasite,
benefits whilst the host does not
What are abiotic factors? Give some examples.
The non-living aspects of an ecosystem
e.g. temperature, water availability, light
intensity, pollutants
Describe how communities are affected by
environmental conditions
● Environmental conditions (e.g. temperature, light intensity,
water availability) affect the abundance and distribution of
organisms within communities
● e.g light intensity affects the rate of photosynthesis in producers
which serve as a source of food and shelter for other organisms
Describe how communities are affected by pollutants
● Toxic chemicals (e.g. pesticides) bioaccumulate in food chains to
deadly concentrations at higher trophic levels, killing tertiary and
quaternary consumers
● Fertilisers that contaminate water sources can cause
eutrophication, killing multiple populations within a community
● Air pollution can affect the ability of some plant species to survive
What are biotic factors? Give some examples
The living components of an ecosystem
e.g. competition, predation
Describe how competition affects communities
● The presence of competitors affects population distribution
and size
● If one species is better adapted to survive in a certain
environment, it will outcompete other species, causing
their populations to decline
Describe how predation affects communities
● Predation affects prey populations within a community
● e.g. if the number of predators decreases, the number of
prey will increase as fewer are killed
● Populations of all other organisms within the food chain
will also be affected
What piece of apparatus is used to measure the
abundance and distribution of organisms in an area?
Quadrat
