6.3.2 populations and sustainability Flashcards
(22 cards)
carrying capacity
maixmum population size that can be supported by an anevironemnt
limiting factors
factors that can decrease brith rate or increase death rate
- determine carrying capactiy by preventing any increase
usually in the carrying capactiy stage what happens
- fluctuations
- environmental changes
example of abiotic limiting factors
- water
- sunlight
- ph
- temperature
example of BIotic limiting factors
- food avilabliity
- predators
- inter specific competition
- ## intra specific competition
describe predator prey graph
- as predaotr population increases, prey decreases as more are eaten
- prey decreases, less food for predators
- so fewer predators can survive, population reduces
- so prey increases as fewer are eaten
- predator gets bigger as can eat more
effects of intraspecific competition on a graph
- factors eg food and space become limiting
- population drops, less competition, population increases
- population increases, competition increases, population decreases
interspecific compoetition niches
- overlapping niches , the more intense the competition
- competetive exclusion
conservation
active manahement
maintenance of biodiversity
human interference
SUSTAINABLE USE OF RESOURCES
preservation
habitats left untouched
how can humans threaten biodiversity
- habitat destruction => land used for roads, building
- agriculture => eutrophication, herbicides, insecticides
- deforestation
- pollution
- hunting
- fishing
- pathogens
- ## introduced species
examples of what u can do for conservation
- provide extra food = increase carrying capacity by removing limiting factor
- prevent predation
- prevent poachers
- helathcare + vaccination against disease
- control grazing
- ## restricted access
example of what u can do in ex situ conservation
- breeding programs
- protext from predator
- give healthcare
- reintroduce into the wild
reasons for conervation
- human responsibiltiy (ethics)
- economic = ecotoursim, drugs
- social = aesthetic purposes
small scale timber production management
COPPOCICING
- stem of a tree cut close to the ground
- multiple new shoots can grow
POLLARDING
- cut higher up so deer (herbivores) cant eat the shoots
ROTATIONAL:
- divide wood into sections and cut a section a year
- deflected succession
- trees cant grow long enough to block light from the organisms below, allows more light to reach floor
- MORE HABITATS, prevents destruction of them
ALL:
- prevent soil erosion by keeping roots, and SOIL MINERALS MAINTAINED
- maintain habitat close to the ground
LARGE scale timber production
- clear felling
-BUT SOO BAD FOR BIOD
So now: - selective cutting (only cut the largest most valuable trees)
- replanting
- position trees a minimum distance apart to reduce competition
- LIMIT size of area gelled
- control pests and pathogens
how do trees and roots usually prevent soil erosion and maintain nutrient levels
- use water
- so prevent the soil getting washed away
- trees contribute to carbon and nitrogen cycles, maintaining nutreint levels
how to manage fishing
- fishing quotas
- net with LARGER MESH so immature fish arent caught
- SPECIES RESTRICTION
- only fishing at certain times of year (NOT in breeding season)
describe normal population graph
- lag phase = adapt to anviro
- log phase, pop increases explonentially
- lots of food avilability and LITTLE COMPEITION OR LITTLE limiting factors
- reaches carrying capacity
- intra specific competition eg food, intER specific compeition eg space food etc, overlapping niches = competetive exclusion
- larger population attracts more predators , and disease spreads quicker
PROBLEMS w managing fishing
- area too large to cover
- fish caught and die but not kept
- monitoring expensive
+- tissue culture
+ unfirom plants
+ can save rare species from extinction
+ quick
+ can reproduce infertile plants
+ PRODUCTION NOT DETERMINED BY SEASONS
- low gd
- all susceptible to same disease
- expensive
if your presdator is gone, why might you population decrease anyway?
- less of you eaten
- less of another eaten
- INTERSPECIFIC between you
- for eg space , food etc
