EEB Exam 3

trophic interactions

consumer is eating a resource (+,-)

true predators

Consume whole, live animals or plants: mostly carnivores, seed-predators, and filter feeders. Short association.

parasitoids

offspring consume and eventually kill live organisms from the inside out. long association.

number of parasites per host

one- expect for hornworm

Behavior manipulating parasitoids

cordyceps and dinocampus coccinellae

brood parasites

one egg-laying species benefits by having another raise its offspring. host's offspring normally die

Grazers

Animals that eat grasses or leaves of other plants. short association. does not kill plant directly

browsers

more woody version of grazing where food is eaten above the browse line. does not kill plant directly. short assosciation

itinerant licker

does not kill host directly

Suckers

does not kill host directly

parasites

organisms that live on or in a host and cause it harm. does not kill host directly. long association

Consumers of whole organisms

invariably cause death of the victim (true predators, parasitoids, behavior manipulation, brood parasites)

Consumers of parts of organisms

usually do not directly cause the death of the victim. (grazers, browsers, itinerant lickers, suckers, parasites)

Adaptations of Victims

selection for defense against consumption

protective adaptations

behavior, morphology, chemistry

Protective behavior

escape, avoid, hide, startle, alarm call

Protective morphology

reduce ability to capture, attack or handle prey. shells, spines, tusks, horns, hair, deciduous appendages

cryptic shape or coloration

transparency, camouflage

Aposematism

warning colorations that advertise chemical defenses

Batesian mimicry

A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators.

Mullerian mimicry

two or more unpalatable species resemble each other

protective chemistry

digestibility as a defense. plants produce compounds that limit digestibility or interfere with proteins

quantitative defense chemicals

amount present can vary. difficult to digest

qualitative defense chemicals

either present or absent toxic compounds. many are absent unless induced by herbivore feeding

nitrogen defense

alkaloids >[3000]. often qualitative

Terpenoids

menthol and citronella >[10000]. both qualitative and quanitative

Phenolics

tannins, flavonoids, ligin. normally quantitative

cost of defenses

-reduced feeding
-refuge crowding
-energetically expensive
-reduce growth, development, reproduction

Adaptions of consumers

behaviors, morphology, chemistry

consumer behavior

finding, capturing, subduing, ingesting or entering, deceiving victims

consumer morphology

teeth, claws, spines, grabbers, tentacles, filters, fancy tongues, etc. Also, cryptic coloration to sneak up on victims.

consumer chemistry

venoms and digestive chemistry

general strategy to capture prey

detect, pursue, catch, handle, consume

ambush predators

rely on stealth rather than speed

Cursorial predators

chase down prey using high speed or endurance

high speed locomotion

short or long distances, movement of whole body or just one part

feeding anatomy

how tooth layout and skull are designed to eat adapted foods

Eye placement

-predators: eyes in front
-prey: eyes on side

venom

it bites you

posion

you bite it

top-down control

when the abundance of trophic groups is determined by the existence of predators at the top of the food web

Mesopredators

relatively small carnivores that consume herbivores

predator-prey population cycles

an interaction between prey with periodic cycles and predators. As the population expands, there is more food available for predators. As it contracts, there is less food available for predators, putting pressure on their population numbers.

dN/dt=rN

observed population growth rate

prey equation (lotka-volterra)

dN/dt=rN-cNP
N- Number of Prey
P- Number of Predators
r- Intrinsic per capita growth rate
c- death rate of prey by predators

predator equation (Lotka-volterra)

dP/dt=acNP-mP
N- Number of Prey
P- Number of Predators
r- intrinsic per capita growth rate
c- death rate of prey by predators
a- conversion rate of prey to predator pop. growth
m- per capita predator death rate

isoclines

lines representing all points when the predator or the prey population has zero growth

Coevolution

Process by which two species evolve in response to changes in each other

Symbiosis

A relationship in which two different organisms live in close association with each other. mutualism, parasitism, and commensalism

Resource Aquisition

trade on resource for another

dispersive

Trade movement for food

defensive

guarding or shelter in return for food or service

Carl Huffaker Experiment

predator (walkers) and prey (jumpers) mites living on oranges

habitat complexity

impeded predator dispersal and prey refuge-- creates cycles

numerical response

change in the abundance in response to prey abundance

feeding rate units

number of prey consumed per predator per unit time

Type 1 functional response

feeding rate=cN (linear). unrealistic with no handling time/limit to predators. some filter feeders

Type 2 functional response

A functional response in which a predator's rate of prey consumption begins to slow down as prey density increases and then plateaus when satiation occurs. ends at value 1/h. specialist predator

handling time

the amount of time that a predator takes to consume a captured prey

specialist predators

predators that show a strong preference for certain prey species

Type 3 functional response

when a predator exhibits low, rapid, and slowing prey consumption under low, moderate, and high prey densities, respectively. generalist

prey switching

predators focus on most abundant prey species

search image

a learned mental image that helps the predator locate and capture food

Generalist

Species that does not rely on a single source of prey

pollinator

An animal that carries pollen from one plant to another of the same species, enabling plants to reproduce.

generalist pollinators

can feed from the flowers of many different species and plants pollinated by many species

specialist pollinators

can only feed from flowers belonging to one or a few species

plants and mycorrhizal fungi

mutualism. plants get nutrients/water while fungi het carbohydrates

plants (legumes) and rhizobium

plant gets fixed nitrogen bacteria get carbohydrates and living space

large seeds

dispersed by animals. animals get fruit and seeds are indigestible

facultative

not essential for survival or reproduction of one or either species

obligate

Required for the survival or fitness of one or both species

intimate

consistent spatial and temporal association. same individuals interacting

intermittent

inconsistent across time/space. possibly different individuals

mutualism and conservation

Loss of dispersers can result in a reduction in plant abundance

joint evolution

selection pressures adapting species together in close ecological interaction over time

tight joint evolution

reciprocal evolution of two closely interacting populations

diffuse joint evolution

adaptations in one population promote adaptation in one or more co-occurring populations

Coevolution Outcomes: Mutualism

positive reinforcement
prevention of cheating

Coevolution Outcomes: Competition

increase in competitive ability
decrease in niche overlap

Coevolution Outcomes: consumer-resource

Arms race between predator (consumer) and prey (resource)
Parasites and hosts: Already covered the red queen hypothesis

cheating

occurs when one species receives a benefit but does not provide one in return

resource partitioning

sympatric species avoid competition by exploiting different resources

Sympatric

geographically overlapping

character displacement

traits differ more when species are sympatric than when they are allopatric

increased competitiveness

ability to outcompete over time

Shannon's Diversity Index (H')

accounts for both abundance and evenness of the species present. -E(Pi*ln(Pi))

range=0-ln(s)
s=# of species

Simpson's Diversity Index (D')

( N-(N-1) ) / ( total n (n-1) )

N = total number of organisms
n = number of individuals of each species

1/EPi^2
range=1-s

primary succession

An ecological succession that begins in an area where no biotic community previously existed

consumer-resource interactions

Interactions in which organisms gain their nutrition by eating other living organisms or are eaten themselves.

browse line

The point up to which deer have been eating foliage
(ex: white tail deer)

smaller organism

shorter predator-prey cycle

Prickly Pear Cactus

invaded australia because there was no predator

biocontrol

The use of a species to control the population growth or spread of an undesirable species

parasite

obtains nutrients from a living host but usually does not kill host. lowers fitness and increases probability of death

pathogens

disease causing agents

alternate host

a substitute primary host for a parasite with low specificity

transmission vector

the thing that will carry the pathogen (water, air, blood/body fluid, animal)

Ectoparasites of animals

Parasites that feed on external surface of host. consume blood/body fluids

alpha diversity

Species diversity at the local or community scale.