BIO 160: Predation

• heterotrophic organisms


  organisms that acquire their energy by consuming organic matter
• carnivores


  consumes animal tissue
• parasitoids


  consists of a group of insects classified based on the egg-laying behavior of adult females and the development pattern of their larvae
• capture efficiency


  c in cNprey
• per capita death rate


  d in dNpred
• predator population growth


  Type of pop growth which depends on the per capita rate at which prey are captured
• predator's functional response


  The relationship between the per capita rate of consumption and the number of prey is referred to as
• predator's numerical response


  this increased consumption of prey results in an increase in predator reproduction
• size of the prey population


  Nprey in cNprey
• Type I functional response


  the number of prey captured per unit time by a predator (per capita rate of predation, Ne) increases linearly with increasing number of prey
• Type II functional response


  per capita rate of predation (Ne) increases in a decelerating fashion, reaching a maximum rate at some high prey popula- tion size
• time spent searching for prey, and time spent handling the prey once it has been encountered


  This time consists of two components
• high, zero


  At ____ prey density, the search time approaches ____ and the predator is effectively spending all of its time handling prey
• Type III functional response


  may be the predator's search image
• profitable


  Although a predator may have a strong preference for a certain prey, in most cases it can turn to another, more abundant prey species that provides more ___________ hunting.
• switching


  Ecologists call the act of turning to more abundant, alternate prey as...
• switching


  In _________, the predator feeds heavily on the more abundant species and pays little attention to the less abundant species.
• aggregative response


  the movement of predators into areas of high prey density
• optimal foraging theory


  hypothesis that natural selection favors "efficient" foragers, that is, individuals that maximize energy or nutrient intake per unit of effort
• Cost


  can be measured in terms of the time and energy expended in the act of foraging
• benefits


  measured in terms of fitness; typically measured in terms of energy or nutrient gain
• searching (Ts) and handling (Th)


  total time spent foraging (T) can be partitioned into two categories of activity
• most, less


  If predators are about, then it may be to the forager's advantage not to visit a ____ profitable, but predator-prone, area and to remain in a ____ profitable but more secure part of the habitat.
• reduced, increased


  failure to capture prey results in _______ reproduction and _________ mortality of predators.
• Red Queen hypothesis


  To avoid extinction at the hands of predators, prey must evolve means of avoiding capture; they must keep mov- ing just to stay where they are
• predator defenses


  a wide range of characteristics to avoid being detected, selected, and captured by predators
• Chemical defense


  use of toxic substances
• cryptic coloration


  colors and patterns that allow prey to blend into the background of their normal environment
• Object resemblance


  resemble other objects
• flashing coloration


  distract and disorient predators
• warning coloration or aposematism


  bold colors with patterns that may serve as warning to would-be predators
• Batesian mimicry


  The mimic, an edible species, resembles the inedible species. Once the predator has learned to avoid the model, it avoids the mimic also.
• Müllerian mimicry


  Type of mimicry which is effective because the predator must only be exposed to one of the species before learning to stay away from all other species with the same warning color patterns.
• protective armor


  for defense
• behavioral defenses


  a wide range of behaviors by prey species aimed at avoiding detection, fleeing, and warning others of the presence of preda- tors.
• predator satiation


  Prey are thus so abundant that the predator can take only a fraction of them, allowing a percentage of the young to escape and grow to a less-vulnerable size.
• permanent and induced


  The predator defenses just discussed fall into two broad classes:
• Pursuit

  Ambush

  Stalking


  Predators use three general methods of hunting:
• Ambush hunting


  Type of hunting wherein predators lay and wait for prey to come along. It requires minimal energy.
• Stalking hunting


  Type of hunting wherein the predator's search time may be great, but pursuit time is minimal.