energy and ecosystems - topic 5 Flashcards
define habitat
the place where an organism lives
define population
all of the individuals of one species living in a habitat
define community
multiple populations living and interacting in the same area
define ecosystem
a community and its interactions with the non-living parts of its habitat
define biotic factor and give 3 examples
living factor
- predators
- food availability
- intra/interspecific competition
- disease
- parasitism
define abiotic factor and give 3 examples
non-living factor
- humidity
- temperature
- soil/water PH
- O2 / CO2 concentration
- light intensity
define niche
the role of a species within its habitat
why cant two species occupy the same niche?
species will be in direct competition and one will outcompete the other
define abundance
the number of individuals of a particular species living in a habitat
what is sampling used for?
investigating the abundance and distribution of species and populations
what are the two types of sampling?
random and systematic
what does random sampling avoid?
bias
describe systematic sampling
sampling points are located at fixed intervals throughout the sampling site.
list two methods that can be used to assess distribution and abundance
transect
quadrat
what are plants called in an ecosystem?
producers
GPP definition
chemical energy store in plant biomass (total energy resulting from photosynthesis).
NPP definition
NPP=GPP-R the chemical energy store in plant biomass taking into account the energy lost due to respiration
what is NPP used for?
create new biomass that is passed on to the next trophic level
Define succession
the change in an ecological community over time
what is the first species to colonise an area called? and give an example
pioneer species
- lichen
how does lichen change the abiotic factors to become less harsh?
death and decomposition of lichen forms a thin layer of humus and so mosses and smaller plants seeds can now survive
can hold more water
more soil depth
what is the final community formed in succession called?
climax community
what does primary succession start with
pioneer species
describe the process of primary succession
- pioneer species such as lichen colonises bare rock
- decomposition of lichen forms humus
- mosses + smaller plants can survive in the depth and nutrients of the humus
- abiotic factors continue to get less harsh until a climax community is formed with a dominant species
what is meant by secondary succession?
succession is disrupted and plants are destroyed, succession restarts but soil is present.
what increases as succession occcurs?
biodiversity
what happens when succession is managed?
earlier stages are miantained preventing a climax a community. a greater variety of habitats are conserved and therefore a greater range of species.
describe and explain how succession occurs (6)
primary
* pioneer pecies
* such as lichen
* occupies bare rock
* decomposes forming humus
* changing abiotic factors
primary succession - intermediate
* seeds can now germinate due to less harsh abiotic conditions
* environment becomes more suitable for new species
primary succession - climax
* environment becomes less suitable for previous species
* final species to colonise = dominant species
* formation of a climax community
why would the NPP of a primary consumer be less than a producer?
- some parts of producer not ingested
- some parts not digestible
- some energy lost as respiritory loss
- some energy lost by excretion
what is the advantage of two species occupying a different niche?
- they dont have to compete for the same food/water/light
- both species can survive
