combined response
the combined effect of functional and numerical responses by consumers on prey populations; determined by multiplying the number of prey eaten per predator times the number of predators per unit area, giving the number of prey eaten per unit area.
exploitation
an interaction between species that enhances the fitness of the exploiting individual - the predator, the pathogen, etc. - while reducing the fitness of the exploited individual - the prey, host, etc.
meristematic tissue
tissue made up of the actively dividing cells responsible for plant growth
negative photoaxis
movement of an organism away from light
parasite
an organism that lives in or on another organism, called the host, deriving benefits from it; parasites typically reduce the fitness of the host, but not generally kill it
pathogen
any organism that induces disease, a debilitating condition, in their hosts; common pathogens include viruses, bacteria, and protozoa
positive photoaxis
movement of an organism toward light
predator
a heterotrophic organism that kills and eats other organisms for food; usually an animal that hunts and kills other animals for food
predator satiation
a defensive tactic in which prey reduce their individual probability of being eaten by occurring at very high densities; predators can only capture and eat so many prey and so become satiated when prey are at very high densities
prey- dependent functional response
a functional response in which rate of feeding by a predator is a function of prey population size only
ratio-dependent functional response
a functional response in which the rate of feeding by a predator is a function of the ratio of prey population size, i.e., the number of prey per predator
standard error
an estimate of variation among means of samples drawn from a population
