55 terms


Levels of Ecological Study
organism, population, community, ecosystems, biosphere
B, b, D, d, r, rmax
B-Total Births
b-births per capita
D-total deaths
d-deaths per capita
r- growth rate
rmax- max growth rate
Survivorship curves
They show the likelihood of survival at different ages throughout the lifetime of the organism.
Fitness trade offs
Occur because every individual has a restricted amount of time and energy at its disposal--meaning that its resources are limited.
The physical ability to reproduce
age structure graphs
the proportion of people approaching reproductive age as well as those of reproductive age
density dependent growth
Pop. growth rate goes DOWN as population density goes UP. Caused by competition, predation, parasitism, disease
density independent growth
population growth limited by environmental factors (natural disasters) regardless of population
Logistic Growth
dN/dt= rmaxN((K-N)/K)
r= rmax((K-N)/K)
r selected species
species with high fecundity and low survivorship.
k selected species
species with low fecundity and high survivorship
the struggle between organisms to survive in a habitat with limited resources
interaction in which one organism captures and feeds on another organism
relationship between species in which both benefit
relationship between species in which one benefits and the other is unaffected
relationship between organisms involving a host in which the host is harmed and the other benefits
interspecific competition
in a community competition for resources between members of different species
intraspecific competition
in a community competition for resources among members of the same species
exploitative competition
when two competing individuals have indirect contact and conflict over shared limited resources. One species is better at obtaining a resource than another
interference competition
when two competing individuals have direct contact and conflict, either physical or chemical, over shared limited resources.
(ecology) the status of an organism within its environment and community (affecting its survival as a species)
n dimensional theory
competitive exclusion principle
ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time
When two species share the same fundamental niche and live together, but neither species goes extinct.
niche differentiation
When species adapt to using different resources when there is high competition for same resource. May be called resource partitioning. Character displacement may/may not happen
habitat heterogeneity
Habitat encompasses the diverse characteristics of the environment that define an area where specific biota live and is necessary for life functions
character displacement
Changes in the physical characteristics of a species' population as a consequence of reducing interspecific competition
ghost of competition past
indirect evidence of earlier interspecific competition resolved by the evolution of niche differentiation
hiding places for prey that stabilize predator-prey cycles
constituative defense
a defense that is always present
inducible defense
a defense that is only expressed (or has hightened expression) when there is significant predation pressure
Top down hypothesis
Top level consumers control community dynamics (e.g. predation)
bottom up hypothesis
bottom trophic level producers control community dynamics
cryptic coloration
aposematic coloration
The bright coloration of animals with effective physical or chemical defenses that acts as a warning to predators
batesian mimicry
a harmless species copies or mimics a harmful species. Hurts the model but benefits the mimic
mullerian mimicry
two harmful species mimic each other. both benefit
relationship in which two species live closely together
red queen hypothesis
states that because all of a species' competitors are continually evolving and becoming more competitive, if a species cannot evolve quickly enough to keep pace with the evolution of competing species, it will become extinct
direct parasite transmission
getting a parasite through direct contact
indirect parasite transmission
getting a parasite from an indirect source or species called a vector.
parasite adaptations
-suckers and hooks for attachment to host, -ability to resist digestive enzymes, -produce a lot of offspring, -loss of sense organs, -loss of digestive system
species area curves
Area vs. number of species: an increase in area = an increase in species
Island biogeography
refers to the theory that species richness on islands is dependent on island size and distance from the mainland.
species richness
the number of different species in a community
island equilibrium model
model of speciation where the equilibrium number of species will be at where the immigration rate meets the extinction rate
innate behaviors
Behavior that appears as an animal develops, apparently without having been learned. Complete without practice.
learned behaviors
behaviors that were taught to an animal and help it meet its needs
classical conditioning
a type of learning in which an organism comes to associate stimuli. A neutral stimulus that signals an unconditioned stimulus (US) begins to produce a response that anticipates and prepares for the unconditioned stimulus. Also called Pavlovian or respondent conditioning.
operant conditioning
a type of learning in which behavior is strengthened if followed by a reinforcer or diminished if followed by a punisher
all the mental activities associated with thinking, knowing, remembering, and communicating
resource partitioning
in a biological community various populations sharing environmental resources through specialization thereby reducing direct competition
poor nutrition hypothesis
a hypothesis which states that plants are a poor food source in terms of the nutrients they provide for herbivores (plant tissues have 10% less nitrogen than animal tissues)
plant defense hypothesis
a hypothesis which states that plants defend themselves effectively enough to limit herbivory. Defenses include: thorns, prickles, hairs, poisons, lignin and cellulose hard to digest
carrying capacity
largest number of individuals of a population that a environment can support