Interspecific Exploitation: Predator-Prey Dynamics

Interspecific Exploitation

Interactions between different species affecting fitness.

Exploitative Interactions

Relationships where one species benefits at another's expense.

Fitness

An individual's reproductive success and survival rate.

Herbivory

Consumption of plant material by herbivores.

Predation

Killing and consumption of prey by predators.

Parasitism

Parasite benefits while harming the host.

Lotka-Volterra Model

Mathematical model predicting predator-prey population dynamics.

Population Inertia

Delay in predator response to prey population changes.

Mutualism

Interaction where both species benefit (+/+ relationship).

Consumption Relationships

Grouped interactions of herbivory, predation, and parasitism.

Moose and Wolves Case Study

Population dynamics observed on Isle Royale.

Exploitative Interactions Count

25,000 interactions among 500 species in Lake Okeechobee.

Herbivore Foraging

Herbivores typically consume specific plant parts.

Plant Defenses

Mechanisms plants use to deter herbivores.

Food Availability

Plants generally more available than animal food sources.

High-Energy Plant Foods

Seeds, fruit, and flowers are least available.

Digestive Tract Length

Herbivores have longer tracts for complex plant digestion.

Carnivory

Killing and consumption of other animals by carnivores.

Prey Population Rebound

Increase in prey numbers after predator decline.

Predator Population Dynamics

Predator numbers increase after prey availability rises.

Energy Flow in Ecosystems

Study of energy transfer among organisms.

Species Interactions

Connections between species affecting ecological balance.

Herbivore Impact on Plants

Herbivory can either harm or benefit plant fitness.

Carnivory

Killing and consuming other animals for food.

Prey Consumption

Prey may be partially or entirely consumed.

Predation Rarity

Witnessing predation is a rare event.

Predator Confidence

Predators hunt when not being pursued.

Higher Quality Food

Animals provide more protein and fat than plants.

Digestive Specializations

Carnivores have simpler digestive systems than herbivores.

Carnivory Specializations

Includes claws, senses, teeth, and speed adaptations.

Search Image

Focus on specific prey type for hunting success.

Prey Confusion

Searching multiple prey types reduces hunting success.

Parasitism

Parasite lives on or in a host without killing.

Endoparasite

Parasite living inside the host organism.

Ectoparasite

Parasite living on the surface of the host.

Host Fitness Reduction

Hosts suffer reduced fitness from parasitic relationships.

Parasitoid

Parasite that ultimately kills its host.

Insect Parasitoids

Lay eggs in hosts, consuming them as larvae.

Prey Defenses

Prey evolve strategies to avoid being eaten.

Standing Defenses

Permanently present defenses against predators.

Inducible Defenses

Defenses that develop in response to predator pressure.

Plant Consumption Rate

15-70% of plants eaten annually by herbivores.

Mechanical Defenses

Physical barriers to deter herbivores.

Tough Epidermis

Hard seed shells and bark protect plants.

Entanglement Devices

Waxy cuticle and hairs deter small herbivores.

Piercing Devices

Structures like cutting edges to harm herbivores.

Cutgrass

Wetland species with silica cutting edges.

Spines and needles

Adaptations for water and food retention.

Polymers

Cellulose and lignin prevent herbivory.

Secondary metabolites

Chemical defenses evolved to deter herbivores.

Phenolics

Compounds that reduce protein digestion in herbivores.

Terpenes

Chemicals that block ion transmission and cause dermatitis.

Alkaloids

Compounds that interfere with neurotransmission and cause nausea.

Mechanical defenses

Physical adaptations to deter predators.

Retaliation

Defensive actions like porcupine quills.

Startling behavior

Mimicking predators to scare off attackers.

Deflection of attack

Redirecting attacks to non-vital areas.

Large size

Intimidation through sheer body mass.

Death feigning

Pretending to be dead to avoid predation.

Fleeing

Quick escape from predators.

Crypsis

Camouflage to avoid detection.

Clustering

Safety in numbers to confuse predators.

Nausea induction

Chemical defenses causing discomfort to predators.

Cellulase

Enzyme evolved by some organisms to digest cellulose.

Alkaline pH

High pH in some herbivores prevents tannin binding.

Mutualism

Partnerships with species aiding in digestion.

Sub-toxic consumption

Eating small amounts of toxic plants.

Induced defenses

Plant defenses activated after herbivory.

Social carnivory

Hunting in groups for efficiency.

Pursuit adaptations

Short vs. long distance hunting strategies.

Luring

Using bait to attract prey.

Sit and wait

Ambush tactics in predation.