Ecology Chapter 19 Predators

Predation

Interactions in which an individual of one species (consumer) consumes individuals of another species (prey/plants)

Types of consumption/predation

Predation (predator and prey are both animals)

Omnivory (predator is an animal or plant and prey is plants and animals)

Herbivory (predator is an animal and prey is a plant or algae)

Parasitism (predator is a parasite and prey is a host)

Key differences between predation and herbivory

Any consumption of prey is likely lethal, but plants can tolerate large amts of consumption

Animals can usually move away from predators, but plants are sedentary

Plant tissue is very different than animal tissue, so herbivores must consume far more than predators and specific adaptations are necessary to consume plants

Most predators are generalists (they’ll eat anything) and most herbivores are specialists (specifically evolved to feed on specific species or parts of species)

Predators only need to consider eating prey, but herbivores must consider eating but not getting eaten

Cursorial hunting

Predator chases prey until tired/prey is caught

Other predators hunting prey strategy

Sit and wait ambush hunting

Prey escapes predators by altering

morphology and behavior, movement, physiology (toxins, mimicry)

Plants attempt to ____ the cost of consumption through ____ and ____

Reduce; Resistance; tolerance

Plant resistance

Chemical defenses like poison or endocrine disruptors or plant volatiles

Physical defenses like spines, thorns, etc

Constitutive defenses

permanent defenses that are always “on”'; active prior to an attack

Inducible Defenses

Defenses that are activated by an attack

Plant tolerance

Compensation or overcompensation to herbivory OR the ability to mitigate negative fitness effects of herbivory

Ways plants compensate/mitigate herbivory

Increased photosynthetic activity of undamaged parts

Compensatory growth to damaged parts

Utilized stored resources

Reallocating resource to unattacked parts then reallocating them back

Increase nutrient uptake

Altering plant architecture (ex increased allocation to roots)

Masting

Produce a huge amount of seeds at once to overwhelm herbivores

Lotka Volterra Predator Prey Model

Describes how predator and prey interactions interact to alter the other’s population abundance

Prey isocline

Horizontal; r/a

Predator isocline

Vertical; m/ba

The LV predator prey model moves ___

Counterclockwise!