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biology module 6.4 - population and sustainability - Coggle Diagram
biology module 6.4 - population and sustainability
conservation
conservation = active management involving human intervention to improve biodiversity
social - people enjoy spending time in nature
ethical - species have value, humans should look after them
economic - environment provides us with necessary resources (income)
preservation = keeping species and habitats as they are now
threats to biodiversity : hunting, poaching, pollution, introduce non-native species, climate change, destruction of habitat
ways to maintain biodiversity : preserve habitats, control poaching, restrict dispersal (via fencing)
population size
lag phase
= low population growth initially because there are few mates to find
exponential growth
= max population growth rate, birth rate higher than death rate
transitional phase
= as the population grows, more competition between population - rate of population growth slows down (but doesn't stop)
plateau phase
= population has reached carrying capacity (K), population growth stops as resources run out - population size remains the same as long as environment remains the same
key words to learn :
carrying capacity (K) = maximum number of individuals that an environment can support
biotic potential = population growth rate at maximum (during exponential growth phase)
environmental resistance = sum of environmental factors that restrict the biotic potential (drought, flood, competition)
limiting abiotic factors : temp, light, pH, humidity, o2/h2o availability
limiting biotic factors : predator, disease, competition
density dependent factors = factors that affect a population depending on their size
density independent factors = factors that affect a population regardless of their size
individuals who follow this population curve : low reproductive rate, long lifespan, large body mass (mammals)
timber production
fisheries
predator-prey graphs explained
reducing predator/prey population size
:
predator eat prey, reduce prey population
few prey for the predators to hunt, predators in competition with each other
predator population reduces as they have few prey to feed on
increasing predator/prey population size
:
fewer predators = more prey survive
more prey = reduced competition between predators, increasing predator population size
