Species interactions, population dynamics Flashcards
play an extremely important role in biological communities and ecosystem function
Species interactions
Styles of interaction
positive, negative neutral
example of positive interaction
mutualism
example of negative interaction
predation, competition, parasitism
example of neutral interaction
commensalism
plays a critical role in an ecosystem; many other species depend on it for resources; ecosystems collapse/decline/alter if it is removed
keystone species
example of keystone species
fig trees bear fruit year round
one organism directly feeding on/using another living organism
predation
result of predation
adaptation: defensive traits (spines, thorns, toxins) and offensive traits (speed, agility, immunity)
mimic venomous or toxic species
Batesian mimicry
two unpalatable species evolved to look alike
Mullerian mimicry
types of coevolution
batesian mimicry and mullerian mimicry
two or more species living in the same area that develop a relationship; often related to coevolution; usually enhances survival/reproduction
symbiosis
fitness of one organism is lowered by presence of another
competition
types of competition
intraspecific and interspecific
same species compete
intraspecific
different species compete
interspecific
affecting the ability of an organism to consume resources/reproduce
interference
overconsumption of resources – e.g., Asian carp in Illinois River
exploitation
mechanisms of competition
interference, exploitation, direct vs indirect contact
results of competition
niche differentiation, adaptation via natural selection, population control/reduction
resource partitioning, exclusion
niche differentiation
Factors that affect growth (r)
internal, external, density dependent, density independent, carrying capacity,
growth and maturation rates, metabolism, fecundity
internal
habitat quality, food availability, species interactions
external
as population increases, so does effect
Density-dependent
affected no matter population size
density-independent
number/biomass of life that can be supported in an area
A dynamic quantity, can vary with changes in habitat
carrying capacity (k)
Species Population Growth Types
r-selected species and K-selected species
High reproductive rates, often overshoot carrying capacity
Lots of young, few survive
r-selected species
Conservative reproduction rates, slow growth near carrying capacity
Fewer young, longer maturation time
k-selected species
Survivorship patterns
Type I – k-selected patterns
Type II – r-selected and k-selected patterns
Type III – r-selected patterns