Like this study set? Create a free account to save it.

Sign up for an account

Already have a Quizlet account? .

Create an account

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

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions and try again


Reload the page to try again!


Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

Voice Recording