Exam 2 pt. 2

Question 1

LV prey-predator isoclines and model dynamics

Answer 1

where there is no change in prey population = reaching a stable outcome (dN/dt = 0)

Question 2

Competition and LV

Answer 2

crowding modifies the prey and predator zero isoclines because mutual interference among predators increases with their density and increased prey density and predators reach an upper density level

Question 3

Mutual interference

Answer 3

the prey population can be limited by crowding through intraspecific competition (logistic limitation). Creates isoclines that are no longer neutrally stable, but are damped to converge to a stable equilibrium

Question 4

Spatial heterogeneity

Answer 4

Aggregated prey show spatial heterogeneity (clumped distributions), and the prey isocline looks like Fig. 10.11, generating stable equilibria quickly (coexistence)

Question 5

Pseudo-interference

Answer 5

generates an aggregation of risk among hosts of parasites; at high parasitoid density, attacked density, attacked hosts are more likely to have been parasitized already

Question 6

Parasite

Answer 6

An organism that obtains its nutrients from one or a very few host individuals, normally causing harm but not causing death immediately

Question 7

Microparasite

Answer 7

More common; Small, very numerous
Multiply directly in host
Mostly INTRAcellular - counted by number of infected hosts
Result in either death or some measure of host immunity

Question 8

Macroparasite

Answer 8

Grow but Do not multiply in host
Produce infective stages to attack new hosts
Live INTERcellularly between tissues or on hosts
Can be counted individually
Multiply outside their host & host response varies according to parasite load

Question 9

Parasite diversity

Answer 9

especially endoparasites, tend to live in very stable host environments
Large advantage against host immunity systems (especially endotherms)
Dispersal achieved through very high reproductive output
Develop defenses against the host immune responses
Diversity and abundance are also influenced by interspecific competition among parasites

Question 10

Host diversity

Answer 10

Experimental host diversity mixtures can influence the spread of diease; can also limit the spread of disease infections;
Effectively diluted the density (contact rate) of susceptibles in the populations and reduces the effectiveness of vectors

Question 11

Host survivorship

Answer 11

Reduced with increasing parasite load

Also reduction in age of maturity, fecundity and population rate of increase

Question 12

Dynamics of parasite populations in hosts

Answer 12

Some degree of bottom-up control, in immune memory
Distributions of parasites within host populations also tend to be aggregated with only a few hosts carrying many parasites
Prevalence and intensity are related through various frequency distributions (shift according to nature of many diseases)

Question 13

Prevalence of infection

Answer 13

the proportion of a host population that is infected

Question 14

Intensity of infection

Answer 14

the number of parasites in or on a single host

Question 15

Decomposers

Answer 15

Saprobes like bacteria and fungi that feed on dead or dying plant and animal tissue

Question 16

Detritivores

Answer 16

feed on the same material once it has been fragmented and processed to varying extents by decomposers and physical events

Question 17

Resources of decomposers

Answer 17

dead bodies of animals/carrion; feces and other excreted products; dead plant material

Question 18

Primary distinction of decomposers/detritivores

Answer 18

Do not affect the rate at which their resources are produced; but predators/herbivores do

Question 19

Host diversity

Answer 19

Effectively dilutes the density of susceptibles in the population and reduces the effectiveness of vectors

Question 20

Host survivorship, age of maturity, fecundity, population rate of increase

Answer 20

reduced with increasing parasite load

Question 21

Epidemic

Answer 21

Rp > 1

rapid increase in the incidence of disease with rapid infection of susceptibles

Question 22

Endemic

Answer 22

Rp ~ 1

the rate of spread is much reduced by increased immunity, mortality and decreased density of susceptibles

Question 23

Feeding guilds of herbivores

Answer 23

grazers, browsers, leaf miners, borers, root feeders, sap suckers, gallers, frugivores, seed predators, pollinators, nectarivores

Question 24

Feeding guild

Answer 24

grouped on nature of exploitation (feeding the same way)

Question 25

Effects of herbivory

Answer 25

Influence the distribution and abundance of plants through effects on plant parts, timing in plant development, post-attack effects (i.e., eating seedlings can change life history)

Question 26

Herbivory Effects - Compensation

Answer 26

Herbivores almost always harm plants, although this may look like benefits

Question 27

Increased Mortality (Herbivory)

Answer 27

repeated defoliation by herbivores can kill or make more susceptible to death

Question 28

Reduced growth (Herbivory)

Answer 28

can slow or stop plant growth, but grasses tend to be resistant to the effects of grazing because the low meristem is unaffected

Question 29

Plant fecundity reduction

Answer 29

smaller plants produce fewer or less viable seeds
Plants may flower later
Herbivores can eat reproductive parts directly

Question 30

Herbivory

Answer 30

The interaction between PLANT DEFENSE and HERBIVORE FORAGING

Question 31

“Optimal Defense” (plant defense theory)

Answer 31

Toxins (small)- effective against abundant generalist herbivores and may account for the effectiveness of some specialist herbivores
Digestibility Reducers (large and expensive) - effective against both specialists and generalists by making nutrients less available to herbivores

Question 32

Apparency

Answer 32

how easy it is to find in space/time

Question 33

Continuous model of detritivory

Answer 33

dR/dt = F(R) - aP

R - resource renewal
F(R) - function of the amount of resource
P - number of predators
a - efficiency with which individuals find and capture their food resource
dR/dt - rate of resource renewal

Question 34

Lotka-Volterra Predation Model

Answer 34

dN/dt = rN - aPN

Question 35

Continuous model of detritivory - MUTUALISTS

Answer 35

dR/dt = F(R) + (delta) M

M - number of mutualists
(delta) - measure of mutual benefit dR/dt

Question 36

Continuous model of detritivory - DECOMPOSERS AND DETRITIVORES

Answer 36

that have no influence on resource renewal

dR/dt = F(R)

Question 37

Detritivores and microbivores

Answer 37

feed on bacteria and fungi
their food is often alive
taxonomically diverse
classified by size

Question 38

Detritivores and microbivores by size

Answer 38

Microflora/fauna - <100 um (cold)
Mesoflora/fauna - 100 um - 2 mm (temperate)
Macroflora/fauna - 2 -20 mm (tropics)

Size groups are influenced by latitudes (biomes; niche distributions)

Question 39

Diversity and abundance of detritivores - woodlands

Answer 39

in woodlands, microbial decomposition is highest

Large detritivores can enhance microbial respiration and function as a connected community (allantoin from woodlice??)

Question 40

Diversity and abundance of detritivores - aquatic

Answer 40

separate into different guilds according to feeding methods (shredders, collector-gatherers, grazer-scrapers, collector filterers)