populations and sustainability Flashcards
dead organisms bad oops
what does the population growth curve look like?
- lag phase (small founder population)
- exponential growth phase (max breeding rate)
- stationary phase (fluctuations so population is at carrying capacity)
what is carrying capacity?
maximum population an ecosystem can support
what is a limiting factor of a population?
limits populations growth or reduce it
what are abiotic limiting factors?
- light intensity
- temperature
- light quality (wavelengths)
- pH
- water availability
they are mostly density independent
what are biotic limiting factors?
- predation
- competition
- migration
- disease
they are density dependent
what is the effect of interspecific competition?
- reduce overall resource level
- results in smaller populations
- better adapted species survive
what is the effect of intraspecific competition?
- competition for the same resources such as territory
- leads to fluctuations in population size
what does the intraspecific competition graph look like?
1: increase - growth and breeding
2: decrease - competition
3: increase - more resources available
what is conservation?
maintenance of biodiversity in ecosystems through human action or management
what does conservation focus on?
- maintaining diversity between species
- maintaining genetic diversity within a species
- maintaining habitats
what is preservation?
protection of an ecosystem by restricting or banning human activity so it remains its original state
why might an ecosystem be preserved?
- ecological sensitivity
- archaeological sensitivity
- palaeontological sensitivity
what are the 3 categories of reasons for conservation?
- economical
- social
- ethical
what are the economic reasons for conservation?
- provide resources for humans
- allows human survival (medicines, timber)
- prevent soil erosion
- genetic diversity
- high biodiversity protects against biotic and abiotic stress
what are the social reasons for conservation?
- benefits to human health
- ecotourism
- enjoyment of natural beauty
what are the ethical reasons for conservation?
- organisms have a right to exist
- moral responsibility
- preservation of keystone species
what are the aims of sustainable management?
- reserve ecosystems
- resource availability in the future
- healthy lives for humans
- allow LEDCs to develop through use of natural resources
- create an even balance between resource consumption between MEDCs and LEDCs
how is small scale timber production sustainable?
coppicing where trees are cut close to the ground so new shoots can grow
how is large scale timber production sustainable?
- selective cutting
- replanting trees
- place trees far apart to reduce competition
- manage pests to maximise yield
how has fishing been made sustainable?
- larger mesh sizes to allow smaller fish to leave and mature
- restricting commercial and recreational fishing to certain times of the year
- protected areas
what are the key features of the masai mara national reserve?
- wildlife reserve
- savannah ecosystem
- divided by a river and fertile lands
what species inhabit the masai mara national reserve?
- acacia bushes
- wildebeest
- tsetse fly
- shrubs and trees
what are the human impacts on the masai mara national reserve?
- tribal livestock graze on the grass and deprive it of nutrients
- trees removed for fuel
what are the conservation methods of the masai mara national reserve?
- ecotourism
- limited grazing around the edges of the land
- employment of reserve ranger
