M6 C24: populations and sustainability Flashcards
(53 cards)
what are limiting factors of population growth?
availability of food
competition between predators#
build up of toxic by products from metabolism
disease
what is phase 1 of the population growth curve/
slow phase
what happens in the slow phase?
small no of individuals that are initially present will start to reproduce. birth rate higher than death rate so increase in population
what is phase 2 of the population growth curve?
rapid growth
what happens in rapid growth?
the number of breeding individuals increase so population multiplies exponetially
what is phase 3 of the population growth curve?
stable phase
what happens in the stable phase?
further population growth prevented by external constraints, small fluctuations
birth and death rates aprox equal
what can limiting factors be divided into?
abiotic and biotic factors
what are abiotic factors?
non living eg light, ph temperature
what are biotic factors?
living such as predators, disease, competition
what is carrying capacity?
maximum population size a environment can support
what is immigration?
movement of individual organisms into a area increasing population size
what is emigration?
movement of organisms away from an area decreasing population size
what are density indeopendent factors?
factors that have an effect on the whole population regardless of size eg earthquakes, fires, volcanoes, eruptions
what are the 2 types of competition?
interspecific and intraspecific
what is interspecific competition?
competition between different species
what is intraspecific competition?
competition between members of same species
what is the result of interspecific competition?
both compete for rescources so become limited for both species, this can limit food and there energy for growth and reproduction and smaller populations
what happens in inter specific competition when one species is better adapted than the other?
less adapted species will be out competed and will decline in number until it no longer exists
‘competitive exclusion principle’
why do fluctuations occur in intraspecific competition?
high availability increases population
population increase leads to limited availability for food so population decrease
less competition now so population increases again
is predataion a biotic or abiotic factor?
biotic
what is stage 1 in the predator/prey relationship?
increase in prey leads to increase in predator population as more food is available so they can survive and reproduce
what is stage 2 in the predator/prey relationship?
increase predator leads to decrease in prey, death rate greater than birth rate
what is stage 3 in the predator/prey relationship?
less prey means intraspecific competition as the predators have to compete with each other as there is less food available. decreases predator population