WFSC 403 1nd Edition Exam 3 Study Guide Lectures 18 Lecture 18 October 28 T F Intra specific competition occurs on same trophic level True What is the difference between trophic food chain and food web A food web occurs on different trophic levels a food chain occurs on the same trophic level What is disease An interaction in which a disease organism lives on or within a host plant or animal to the benefit of the disease agent and the detriment of the host What is virulence The degree or ability of pathogenic organism to cause disease often measured by the host death rate T F Parasites always kill their host False What are sub lethal effects Affect behavior in adverse way fever is an example How could sub lethal effects effect the population Could effect reproductive rates What are macroparasites and what are some examples of them Large multicellular organism that cause disease that often do not reproduce in the host but lay eggs inside of the host but hatch outside of the host It may kill the host may not Tapeworm is an example What are microparasites and an example of them Microparasites are single celled that are detrimental to host that is in Pathogen can cause disease What is the red queen hypothesis Coevolution is occurring but the populations are just running and running but never gets anywhere neither really improves Predator gets more efficient at catching prey prey gets better at evading predators What is another name for the red queen hypothesis Evolutionary arms race What is the difference between disease and parasites Microparasites usually cause diseases Small single cell organisms that are detrimental to host that it is in Pathogen can cause disease Reproduce in host Macroparasites are usually parasitism They are multicellular such as tapeworms and ticks Feeds on host at expense of the host may kill the host may not depends Lays eggs in host but doesn t really reproduce in host What does SIR stand for Susceptible infected recover T F Virulence of a pathogen depends on the intensity of the disease it causes and is measured by host mortality False Lecture 19 November 4 What is the difference between what disease and parasites do to a host Macro disease agents reproduce in host Parasites do not reproduce in the host they don t complete life cycles in host How is virulence measured Often measured by death rate What is One Health and why is it important Integrate human and veterinary medicine helpful because Pathogens are common and passed between each Lecture 20 November 6 How do you maximize R0 Does disease affect populations Under what conditions does an epidemic occur R0 is greater then 1 Equivalent to net reproductive rate intrinsic rate of increase of pathogen Transmission rate recovery rate means going to infect other individuals What is Recovery rate Can a disease effect populations And if so how can you measure it Please describe these values X number of susceptible Y number of infected N Total number of individuals b instantaneous birth rate of the host constant d instantaneous death rate of the host constant c contact rate a function of population density N transmission rate per encounter Under what conditions is there an epidemic R0 is greater then 1 What is cryptic cycle From a human point of view the pathogen is cycling in cryptic sort of way We only care about it when it jumps to a host we do care about Lecture 21 November 11 T F Simple host parasite models cannot predict extinction stability or stable cycles False Brucellosis in Bison why are small herds less likely to have it spread The contact rate is too low and they could run out of susceptible individuals Why doesn t the disease run through the big herds of bison There are more baby bison being born and the period that an individual is infect and infectious is relatively short Lecture 22 November 13 T F To stop population growth natality mortality or movement rates must not change with population False If a factor is density independent a graph of population density versus the rate ex Per capita mortality rate will have a slope that is what Zero T F Allee effects occur when population growth rates decrease below replacement level at low population density potentially leading to extinction True If a factor is density dependent a graph of population density versus the rate ex Per capita natality rate will have a slope that is what Either negative or positive T F biotic agents such as predators and diseases can limit or regulate populations but climatic and physical factors such as temperature and nutrients cannot False Lecture 23 November 18 What stops population growth To stop population growth natality mortality or movement rates must change with population density Population regulation requires density dependence What determines average abundance Biotic agents such as predators and diseases can limit or regulate populations as can climatic and physical factors such as temperature water and nutrients Individual differences in physiology genetics or behavior can limit or regulate populations through intraspecific competition for resources What is the allee effect Population growth rates that decrease below replacement level at low population density potentially leading to extinction What is a sink population and source population Sink population local populations in which the rate of production is below replacement level so that extinction is inevitable without a source of immigrants Net excess of mortality immigration exceed emigration Source population local populations in which the rate of production exceeds replacement so that individuals emigrate to surrounding populations Net excess of reproduction emigration exceeds immigration If populations do not increase without limit what stops them A population in a closed system will increase until it reaches equilibrium point at which per capita birth rate per capita death rate Do you expect ecological systems to be near or at equilibrium most of the time No they are usually varying around state space not too close to equilibrium or other boundaries Lecture 24 November 20 What determines if an individual or population is successful If the individual lives to reproduce they are successful T F Selection occurs at the level of the individual evolution does not occur at the individual level True Name two things that affect birth and death rate Behavior Stress Genetic Dispersal k or r Which is a better competitor and better suited for areas with higher