Exam 3

6 types of species interactions

6 types of species interactions

1. predation/parasitoidism

2. parasitism

3. herbivory

4. competition

5. mutualism

6. commensalism

which 3 species interactions are trophic interactions

predation/parasitoidism, parasitism, and herbivory since all are (+,-)

Trophic Interaction

Consumer eating a resource; involves the transfer of energy/nutrients across trophic levels

True Predators

Consume whole, live prey (animals or plants)

True predators consist of what?

Carnivores, seed-predators, and filter feeders

What are the effects of true predators?

Large impact on prey populations and natural selection

Parasitoids

Offspring consume and eventually kill live organisms from the inside out

What organisms are often killed by parasitoids?

Many insects (especially larvae) and seeds are killed this way

How many parasitoids per host usually?

One per host

What is the genus of fungi that are parasitoids associated with behavior manipulations?

Cordyceps

What is an example organisms that cannot be classified to a species interaction?

Blood parasites

What 3 types of organisms are included in consumers of parts of organisms?

Grazers, browsers, and itinerant lickers and suckers

Grazers, browsers, and itinerant lickers and suckers consist of what?

Most herbivores, suckers of plant juice, nectar, bloodm and hemolymph

Herbivory often doesn't kill prey (1), but instead consumes part of the prey and (2) prey probability of death and (3) fitness.

1. Directly

2. Increases

3. Lowers

Grazing vs Browsing

Grazing: herbaceous, ground level Browsing: more woody, higher

Name an advantage for grazing and browsing:

Grazing: less woody (more nutrients) Browsing: more accessible year round

Parasite

Live on or in the host/victim

How do parasites effect hosts?

Often doesn't kill host directly but consumes part of the host and lowers its fitness

What are the 3 forms of adaptations used by prey and consumers?

1. Behavior

2. Morphology

3. Chemistry

Protective behavior can include what 5 behaviors in prey?

1. Escape

2. Avoid

3. Hide

4. Startle

5. Alarm call

Protective Morphology (prey)

Structures or coloration for defense or deception

Protective morphology can do what to help prey?

Help reduce the ability for predators to capture, attack, or handle the prey.

What 6 protective morphology traits help reduce capture, attack, or handling in prey?

1. Shells

2. Spines

3. Tusks

4. Horns

5. Hair

6. Deciduous appendages

Cryptic (shape or coloration)

Transparency and camouflage

Aposematism

Warning coloration; associated with a harmful, usually chemical, defense

Batesian Mimicry

A harmless organisms mimics a harmful one

What 2 things can prey animals do to have protective chemistry?

1. Incorporate ingested toxins

2. Make their own toxin

Prey animals with protective chemistry often have (1) coloring.

Aposematic

Mullerian Mimicry

Two or more distasteful or poisonous species come to resemble one another

What can prey plants do to have protective chemistry?

Produce compounds like limit digestibility

What are the 2 types of protective chemistry in prey plants?

1. Quantitative Defense Chemicals

2. Qualitative Defense Chemicals

Quantitative Defense Chemicals

Amount present varies continuously, difficult to digest

Qualitative Defense Chemicals

Present or absent, toxic chemicals

What are 3 chemicals associated with prey plant chemical defenses? Quantitative or qualitative?

1. Nitrogen compounds - often qualitative

2. Terpenoids - both

3. Phenolics - often quantitative

What is an example of a nitrogen compound used for prey plant chemical defenses?

Alkaloids

What are 2 examples terpenoids used for prey plant chemical defenses?

1. Citronella

2. Menthol

What are 3 examples of phenolics used for prey plant chemical defenses?

1. Tannins

2. Flavonoids

3. Lignin

What are the 2 costs of defenses in prey? (behavior and morphological/chemical)

1. Behavioral: reduced feeding activity or refuge crowding

2. Morphological/chemical: energetically expensive

Having defenses can reduce what 3 things in prey? (costs)

1. Growth

2. Development

3. Reproduction

What are 5 behavior adaptations used by consumers?

1. Finding

2. Capturing

3. Subduing

4. Ingesting or entering

5. Deceiving victims

What are 7 morphological traits used by consumers?

1. Teeth

2. Claws

3. Spines

4. Grabbers

5. Tentacles

6. Filters

7. Fancy tongues

True or false: only victims use cryptic coloration

False, consumers can use it to sneak up on victims

What are 2 chemistry adaptations used by consumers?

1. Venoms

2. Special digestive chemistry

What do behavior adaptations do for consumers?

Help capture and subdue prey

What are 3 behavior adaptations / type of predators are used by consumers?

1. A sequence

2. Ambush predators

3. Cursorial predators

What is the sequence (5 parts) in a behavior adaptation for consumers?

Detect, pursue, catch, handle, and consume

Ambush Predators

Predators rely on stealth rather than speed

Cursorial Predators

Predators chase down prey using high speed or endurance

High-speed locomotion can be at (1) distances and can include movement of (2).

1. Short or long

2. The whole body or just one part

What are 4 morphological adaptations used by predators?

1. Weaponry

2. Feeding anatomy

3. Cryptic coloration

4. Eye placement

What are 2 chemical adaptations used by predators?

1. Having different types of venom (hemotoxic, neurotoxic, etc.)

2. Having venom tolerance

What can herbivores do when plants have defense chemicals?

Tolerate chemical defenses

Top-Down Control

Abundance of a population can be limited by its predators/herbivores/parasitoids

Since many top predators are (1), the top-down impacts are (2) to substantiate.

1. Gone

2. Hard

What are 2 examples of evidence (introduced and recovering predators) of difficulty substantiating top predator effects?

1. Introduction of brown tree snakes to Guam devasted fauna

2. Return of wolves to Yellowstone had direct impacts on prey and mesopredators and indirect impacts throughout the community

In predator-prey population cycles, how does the size of the predators and preys effect length of cycles?

Smaller organisms have shorter cycles

Which number, predator or prey, "follows" behind the other

Predator numbers "follow" behind prey

What does it mean for prey when rN = cNP?

Prey population has 0 growth

What does it mean for prey when rN > cNP?

Prey are increasing

What does it mean for prey when rN < cNP?

Prey are decreasing

What does it mean for predators when acNP = mP?

Predator population has 0 growth

What does it mean for predators when acNP > mP?

Predators are increasing

What does it mean for predators when acNP < mP?

Predators are decreasing

Isoclines

Lines representing all points when the predator or the prey population has 0 growth

Phase-Plane Diagram

Diagram shows joint population trajectory

What happens if N and P are exactly at the joint equilibrium point?

No cycles occurring

What do the "corners" of the phase-plane diagram describe?

The 4 stages of predator-prey population cycles

Predators and preys are always (1) cycle out of cycle.

1/4

What happens to the period length when r or m increases?

Period decreases so cycles become faster and shorter

What are 2 main assumptions of the Lotka-Volterra Predator-prey model?

1. No density dependence

2. No "real foraging behavior"

What were the Carl Huffaker's experiments?

Predator and prey mites lived on oranges

What happened in Huffaker experiments when habitat complexity was added?

Predators could not find prey as easily, lead to cycles

Numerical Response

Change in predator abundance in response to prey abundance

What are 2 examples of numerical responses?

1. Births and deaths

2. Immigration/emigration

Faster numerical responses can lead to what?

Quick reduction in prey numbers

Functional Response

Relationship between prey density and predator feeding rate

How many different types of functional responses are there?

3 - Type I, II, and III

Type I Functional Response

Prey consumption increases linearly with prey density

Equation for Type I Functional Response

feeding rate = cN

Why is type I functional response unrealistic?

Ignores handling time and other limits to predator feeding rate

What is an example of an organism with type I functional responses?

Some filter feeders

Type II Functional Response

Prey consumption plateaus as prey density increases

Equation for Type II Functional Response

Maximum possible feeding rate = 1/h

What 2 things does type II functional response take into account?

1. Handling time (h)

2. Predator satiation

What is an example of an organism with type II functional responses?

Specialist predators

Type III Functional Response

S-shaped relationship where feeding rate is initially low and increases with prey density

What 2 things does type III functional response include?

1. Prey switching

2. Search image formation

Prey Switching

When predators change diet to more abundant prey

Equation for Type III Functional Responses

Feeding rate increases less at higher densities - plateau at 1/h

What is an example of an organism with type III functional responses?

Generalist predators

What type of functional response is assumed in Lotka Volterra predator-prey equations?

Type I

What are the 2 main applications of consumer-resource dynamics?

1. Predict consequences of changes in consumer and resource populations

2. Management, conservation, and biocontrol

What is an example of a cosumer-resource application in the field with biocontrol?

Prickly pear in Australia

Coevolution

Evolution of interacting species in response to each other

Symbiosis

2 different species live in a close physical relationship

Symbiosis includes what 3 species interactions?

1. Mutualism

2. Parasitism

3. Commensalism

Most of the earth's biomass is made up of what type of organism? (related to species interaction)

Mutualists

What 2 key transitions in the history of life are associated with mutualists?

1. Symbiotic origins of eukaryotes

2. Colonization of land by plants

Does mutualism mean there are no costs in the interactions?

No, just that gain > loss

What are the 3 categories of mutualism?

1. Exchange of goods and services

2. Intimacy of association

3. Level of dependency