Population Ecology Flashcards
population
a group of organisms of a specific species that live in the same area and are able to breed freely with each other
ecology
the study of an ecosystem where organisms interact with each other and their environment
population ecology
looking at a population and the factors that affect its size
species
a group of organisms that are similar and are able to reproduce under natural conditions to produce fertile offspring
population parameters
natality, mortality, emigration and immigration
increasing population
natality and immigration
decreasing population
mortality and emigration
migration
the temporary, seasonal movements following the food and water resources
closed population
no immigration or emigration, only mortality and natality will affect population size
fecundity
number of births per thousand per year
direct methods for determining population size
census - counting every individual but the must be large and within a reasonable area
indirect methods for determining population size
mark-recapture or quadrant method
precautions for determining population size
no hurting of animals, must not affect movement or behaviour, mark cant make the animal more visible to its preditor
carrying capacity
the maximum number of one species that the environment can sustain
types of population growth
exponential and logistical
stable population
fluctuates around the carrying capacity
unstable population
the population exceeds the carrying capacity which makes the habitat deteriorate rapidly
factors that affect population size
density-dependent or density-independent factors
density-dependent factors
limit population growth as a result of the population density. eg. competition for food, disease or parasites
density-independent factors
changes in rainfall, temperature, humidity or catastrophic events
predation
the biological interaction where one species, the predator, kills and eats another species, the prey
how do predators help create and maintain greater diversity within an ecosystem?
by regulating the abundance and distribution of the prey species and keeping the prey population genetically fit
aphid-ladybird
female ladybirds lay eggs amongst aphid colonies. the adults then feed on the aphids
lion-zebra
depend on each other for survival. adaptation is the speed of movement
shark-fish
shark keep fish populations healthy
keystone species
a species that has. disproportionally large effect on its environment relative to its abundance
competition
when two or more individuals compete for the same resources that are in short supply
two types of competition
intraspecific and interspecific
intraspecific competiton
between individuals of the same species competing for resources or mates. is the most intense form of competition
interspecific competition
between individuals of different species where the conditions necessary to survive and reproduce are similar
two types of interspecific competition
competitive exclusion or competitive coexistence
competitive exclusion
when one of the two competing species is more successful. can result in extinction and out competition
competitive coexistence
when two species coexist because they use the resources differently which is resource partitioning
resource partitioning
a process where species with similar requirements living in the same habitat have traits that allow them to use their resources differently.
how are resources partitioned
different time, different parts of habitat, different parts of the same plant
giraffe and kudu
giraffe eat top, kudu eat tree shoots
shorebirds
pickers and probers - probe underground, feed off the shoreline, prey on creatures living in deeper water
Lions and leopards
hunt at different times hunt different prey, hunt in different areas of the same habitat
how humans intervene to control community structure
by culling which is the reduction of a wild animal population by selective slaughter
