Populations in ecosystems (Topic 7C) Flashcards
define ecology
The relationship of organisms with their living and nonliving environment
define population
all members of a species found in a particular area at a particular time
define community
all the populations in the ecosystem
define ecosystem
a community and the physical environment
define abiotic factors
the non-living things in an ecosystem
define biotic factors
the living things in an ecosystem
define producer
any plant that manufactures food by photosynthesis
producers are also known as…
autotrophs
define consumer
organisms that eat producers and/or other animals
define decomposer
organisms that break down dead organisms making their materials available to other living things
decomposers are also known as…
detrivores
define habitat
the place in the ecosystem where an organism lives
define niche
an organisms role in the ecosystem
define biome
an area on the earth identified by climate, plant and animal life
define the carbon cycle
the movement of carbon in nature
define the nitrogen cycle
the movement of nitrogen in nature
what is the method for mark, release, recapture?
- Capture in a non-harmful way
- Mark in a way that is non toxic and doesnt impact on survival.
- Release back to habitat & allow time for intermingling
- Recapture
what is the equation that goes alongside mark, release, recapture?
(total in first x total in second) / no. of individuals recaptured
when grass is grown in a field fewer nitrate ions are lost than when the field is left with bare soil. explain why
(2 marks)
the presence of grass causes less nutrients to be leached
describe the role of microorganisms after a field of crops is ploughed
(5 marks)
- microorganisms break proteins down
- ammonification
- conversion to nitrates
- by nitrifying bacteria
- nitrates absorbed into roots of new crops
why are phosphates needed by a growing plant?
3 marks
- for production of phospholipids in cell membrane
- synthesis of ATP
- production of DNA
why is it important for a farmer to reduce the leaching of nitrates?
fewer nitrates in the soil for the next crop requiring more application of fertiliser needed
explain how the use of inorganic fertilisers on fields leading to a lake no longer having any plants or fish anymore
6 marks
the run off of fertilisers
leads to increased algae growth
increases competition for light
causing death of plants
which increases food supply for microorganisms
respiration of microorganisms used up oxygen
fish die die to lack of oxygen
explain how including leguminous plants in a crop rotation reduces the need to use artificial fertilisers
2 marks
they contain nitrogen fixing bacteria in foods so when the die they add nitrogen containing compounds to the soil
application of very high concentrations of fertiliser to the soil causes plants to wilt. explain why
2 marks
lower water potential in soil than in the plant which prevents roots from taking up water
give the equation that links gross productivity and net productivity
net productivity = gross productivity- respiratory losses
why is an animals mean energy expenditure higher in colder months
the temperature was colder so they needed more energy to maintain its body temperature by respiration
interspecific competition is when…
organisms of the same species compete with each other for the same resources
intraspecific competition is when….
organisms of different species compete with each other for the same resources
predation is when…
an organism (the predator) kills and eats another (the prey)
succession is…
the process by which an ecosystem changes over time
primary succession happens on what kind of land?
newly formed or exposed land
the species that is first to colonise a new land surface is called….
the pioneer species
why can only the pioneer species grow on new land?
conditions are hostile and only this species is adapted to cope with these conditions
how do pioneer species change the abiotic conditions?
they die and microorganisms decompose the dead organic material forming basic soil
a climax community is…
the ecosystem is in a steady state with its most complex community of plants and animals
secondary succession happens on…
land thats cleared of plants but where the soil remains
e.g. after a forest fire
the climax community for a particular climate is called….
climatic climax
conservation is…
the protection and management of species and habitats in a sustainable way
what are 5 methods of conservation?
- managment of succession
- seed banks
- captive breeding
- fishing quotas
- protected areas
the carrying capacity is the….
maximum stable population size of a species that an ecosystem can support
