Population Dynamics & Ecology: Endemic & Cosmopolitan Species, Demography, Growth Model, &, Exams of Nursing

Download Population Dynamics & Ecology: Endemic & Cosmopolitan Species, Demography, Growth Model, & and more Exams Nursing in PDF only on Docsity! 2024 Bio 2200 midterm # 2 study guide Solution University of Virginia Regular logistic growth - -Goes up exponentially then plateaus Niche - -The range of abiotic and biotic conditions an organism can tolerate/handle Fundamental niche - -the range of abiotic conditions under which a species can persist Realized niche - -the range of abiotic and biotic conditions under which the species can persist fundamental/realized niche of american chestnut - --Fundamental niche: Is climatic and soil conditions throughout eastern USA. - Realized niche: Almost non because of introduced biotic factor. could the realized niche ever be larger than the fundamental niche? - -yes, the presence of a muralist can allow a species to survive where it couldn't survive on its own. (Plants with nitrogen fixing bacteria) How does the realized niche determine the geographical range of a species - -Places on the globe where abiotic and biotic conditions are within the range of condition the spcies can tolerate=Geograpgical range Make an Experiment Hypothesis:Sugar maple cannot grow further to the west becasue it is too dry there. - -Treatment: Water with amount of water matching natural precipitation in Lethbridge. Control: water with amount matching areas within its geographical range Replication: 100 seedlings in each group Randomization: Choose seedlings to get treatment vs control randomly Prediction: If the hypothesis is correct then the treatment group will have a higher mortality than seedling in control ecological niche model - -Used to predict locations in a region that have suitable conditions for a species. 2 reasons why a spcies might be absent from a location that an ecological niche model predicted to be suitable? - -1) Biotic factors are not suitable (Competitors) 2) Site is suitable for a species to grow. but the species cannot get there. (Barrier) Endemic species - -Lives only in a small localized region Cosmopolitan species - -Has a large geographical range CHaracteristics of population distrubution - -1) Geographical range 2) Abundance- (# of individuals) 3) Density- (# of individuals per unit area or volume) 4) Dispersion- Clustered, evenly spaced and random (Spacing of the individuals) 5) Dispersal- (Movement of individuals from one area to another for GOOD) Cause of clustered dispersion pattern - -- Clonal reproduction - resources are clustered A biologist who studies 2 species of barnacles notices that the smaller species (Chthamalus) is found from the high tide line to just below the high tide line, whereas the larger species (Balanus) extends down from just below the high tide line to the low tide line. He hypothesizes that the fundamental niche of Chthamalus actually extends down to the low tide line as well, but that it is limited to a narrower realized niche due to competition from Balanus. Design an experiment to test this hypothesis. Be sure to describe the treatment, the control, the prediction, the replication and randomization. - -Treatment: Treatment will involve completely removing the larger species from the high tide line to the low tide line while leaving the smaller species where it naturally occurs. Continual maintenance will be required to keep larger barnacles off the rock giving the smaller species an opportunity to expand if it is capable. Control: The rocks with naturally occurring populations will be left alone. Replication: Selected rocks will need to be from multiple different areas in the native range of the both barnacles so as to have equal opportunity to grow. Randomization: Since multiple areas are being used, each area will need to have both control and treated rocks so localized factors, such as predator activity and nutrient distribution, that may inhibit natural growth will be less of an issue. Prediction: If the hypothesis is true, then treated rocks will have a larger population of small barnacle in all depth of the rock from high tide to low tide Demography - -Study of populations Geometric growth model - -- compares population sizes at regular time intervals. - Used for species who reproduce all at once, once a year. Geometric growth formula: λ=Nt/N1-t λ= N0/N1/N2...etc= - -- Growth rate - Population size during a specific time exponential growth model - -- Model's rate of change increases exponentially. - For species who reproduce continuously. (eg. human) exponential growth formula Nt=N0e^rt - > - -exponential growth Doubling time - -The time required for a population to double in size Density independent regulation - -When birth or death rates do not change with population density. density dependent regulation - -factors that affect population size in relation to population density negative density dependent regulation - -at higher densities there are fewer resources per individual, therefore growth rate decreases positive density dependent regulation - -- growth rates are lower at low population density - low density, hard to find mates (allele effect) allele effect - -individuals in a population may have a hard time surviving or reproducing if population size is too small. individual fitness decreases as population density decreases Bird population studied for 25 years - -- Higher egg survival= higher population growth rate - Egg survival declines as bird density increases - Negative density dependent Populations can be regulated by both positive and negative density dependent factors - -- as population density gets larger, more competition for resources and growth rate decreases - As low populations density, positive density dependance logistic growth model - -a growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment. - Infection point is the point in the middle where the fastest growth is happening - ((dn/dt)=rN(1-(N/K))) carrying capacity - -The max population size that can be supported by the environment Age structure pyramids - -show the relative number of individuals of each age in a population and can be used to predict and explain many demographic patterns Life tables - -Display class specific survival and fecundity data Types of life tables - -cohort life table and static life table cohort life table - -follow a group of individuals born at the same time until they all die static life data - -quantify fecundity and survival of individuals (all ages) at a single time interval - = fraction of patches occupiedp̂ - e= probability of extinction for each patch - c Probability of colonization basic metapopulation are hard to find in nature because - -- Patches are different sizes, different quality, matric is not totally inhospitable, different distances between patches in basic metapopulations # of individuals in a subpopulation depends on - -1) Distance from other patches 2) size of patch rescue effect - -When individuals dispersing to a patch from another patch prevent that subpopulation from going extinct Two species of mice are similar in many characteristics. However, species A has large fat reserves that increase survival over periods when environmental resources are depleted, while species B has no fat reserves. Which species is more likely to exhibit oscillating populations dynamics (i.e. stable limit cycles or damped oscillations) rather than the typical logistic growth pattern? Explain your answer. - - Species A will most likely experience stable limit cycles as they can rely on transient fat reserves that allow them to continue to reproduce past the carrying capacity even after the resources have been used up. Since their fat store is finite, once it is used up and resources are still low, the population will experience a large die off and fall below the carrying capacity. Species B's population is heavily controlled by the resources available and will therefore reach the carrying capacity and the population will remain stable due to low reproduction and survival rates. Species B oscillations will be smaller than Species A and closer to typical logistical growth. Two types of predators - -1) Mesopredators 2) Top predators top predators - -predators that typically consume both herbivores and mesopredators Mesopredators - -relatively small carnivores that consume herbivores herbivors - -Eats producers Lotka-Volterra mathematical Model - -to explain mathematically why and how predator-prey populations cycle in relation to each other prey abundance =N - ΔN: dN/dt=rN-cNp - -r= Intrinsic growth c= capture efficiency P=Probability of an encounter between predator and prey Predator abundance= P ΔP: dP/dt=acNP-mP - -a= Convertsion efficiency (how many new predators can be made) m= Mortality rate acNP= Birth of predators c= capture efficiency prey abundance =N Lotka-Volterra Model - -A model of predator-prey interactions that incorporates oscillations in the abundances of predator and prey populations and shows predator numbers lagging behind those of their prey. 1) Increase in prey leads to increase predators (dN/dt=0) 2) Prey start to decline due to more predators (dP/dt=0) 3) Predators in decline due to abundance or prey 4) Once predators below a certain level, prey start to increase again and the cycle goes on. functional response - -- the relationship between prey density and an individual predators rate of consumption - Change in the rate of food consumption with a change in density of prey - as more prey available, each predator gets to eat more functional response type #1 - -predator eats more and more as prey density increases, until reaches satiation Functional response type #2 - -number of prey consumed slows gradually until satiation (due to time handling) functional response type #3 - -- low rate of consumption at low prey density - Then increases quickly - Then slows down gradually (handling time) Numerical repsonse - -Change in the number of predators in response to change in density of prey 1) Population growth 2) movement Defenses against predation and herbivory - -1) Behvioural- Alarm calling, running, reduced activity 2) Crypsis - Camo 3) Structural - Quils, spikes, prickles 4) Chemical defences- Toxins 5) Tolerance to herbivory, (Grass can regrow when eaten by the top) Defense examples - -Persimmon trees immature fruit contains toxins which is an example of chemical defense endoparasite viruses - -Smallpox, west nile, influenza, tobacco mosaic virus endoparasite Prions - -Mad cow disease, chronic wasting disease endoparasite Protozoans - -Malaria, avian malaria endoparasite Bacteria - -Anthrax, pnumonia, plague, salmonella, STDs endoparasite Fungi - -Dutchelm disease, Chestnut blight, rust (crops), White nose syndrom, Chytrid fungus (amphibians) endoparasite Helminths - -Hookworm, lungworm, lung flake White nose syndrom - -- An emerging infestations on bats in NA - Identified in 2006 on bats in a cave in NY state - Fungus -Geomyces destrctans - by 2012, 75 million bats had been killed in NA Why are European bats not dying from white nose syndrome? - -Co-evolution: Bats in Europe have adapted to the fungus over many years, are tolerant and resistant, while in north america it is fairly new Co-evolution - -host adapts to the parasite causing the parasite to adapt to those changes and so on Co-evolution of bats in europe - -- Fungus and bats lived together long time in europe - bats survived have higher fitness therefore bats evolve resistance - Fungus has higher fitness if it does not kill all of its hosts and evolved to become less lethal - North american bats havent had long enough to build resistance Red queen hypothesis - -Sexual reproduction is favoured because it allows hosts to evolve at a rate fast enough to match the rapid evolution of the parasites Vertical transimission - -Parasite is transfered from parent to offspring Horizontal transmission - -Individual transfers parasite to another individual Vector - -An organism that a parasite uses to disperse from on hosts to another. (eg. Mosquito is vector for malaria) How can parasites avoid killing all their hosts? - -1) Evolve ability to infect a different host when host density is low 2) Evolve to be less lethal 3) Live in the environment or in a reservoir species until the host population recovers Reservoir spcies - -Species that carry a parasite but do not get the disease that the parasite cause in other species. (eg SARS, Bats carry but do not get sick SIR model - -A compartmental model with three compartments: susceptible, infected, and recovered. Mathematical model of infectious disease trasmission: (SIR model) Ro=Sx(b/g) - -Ro= Reproductive ratio of the infection S= Number of susceptible individuals b= Rate of transmission g= Rate of recovery Ro>1 is an epidemic Ro<1 Infection will die out What would make Ro smaller? Ro=Sx(b/g) Ro= Reproductive ratio of the infection - -1) Lowering rate of transmission (b) 2) Increase rate of recovery (g) eg. Increase baseline health 3) Reduce susceptibility eg. Vaccines What is competition? - -A negative interaction between 2 species or individuals that depends on the same limiting resource to survive, reproduce and grow. intraspecific competition - -Competition between same species Interspecific competition - -Competition between 2 different species What is a resource? - -any necessity of life, such as water, nutrients, light, food, or space. - If you say "oh no there isnt enough BLANK for all of us", then its a resource Small balsam plant: Fertilized plants - -their growth increased continuously with more light When N2 = 0, n1=k When N1=0, N2=K Limitations of simple 2-species competition model: - -- Based on 1 resource only - Two species are only competing with each other (in isolation, which is not normal) - Doesn't account for abiotic or noncompetition factors Trade-offs between being a good competitor and resisting predation or herbivory - -Animals that move around and feed a lot tend to be good competitors, but because they are moving around a lot, they are more susceptible to predation Exploitive competition - -individuals consume and reduce a resource to the point that other individuals can't survive Interference competition - -competitors defend resources to prevent competition Apparent competition - -When two species negatively affect each other via an enemy (could be predator, parasite, or herbivore) Mutusalism - -A positive interaction between 2 species in which each spices gets a benefit from the other Ants and acacia trees - -- Acacia tree provides nectar to ants - Ants provide deference against herbivores Ants and acacia trees experiment - -Treatment: Exclude ants from leaves Control: leave ants on tree Replication/Randomization: 20 random tree to be treatment and 20 random trees to be control Measure- 1) # of herbivore insects on each tree. 2) Survival of trees over 10 months Prediction: If ants are providing benefit then we predict more trees would survive when they have ants Obligate mutualist - -cannot survive without its partner; require each other to persist facultative mutualism - -Can live without their partner if necessary; both species can survive alone generalist mutualists - -One species can form a mutualism with many different species Specialist mustualist - -One species can form a mutualism only with one particular species What do spcies get from mutualisms? - -1) Protection from predators and parasites 2) Nutrition/food 3) Shelter 4) protection for competition 5) Pollination 6) seed dispersal Plants and mychrorizal fungi mutualist example - -- Plants get nutrients - Fungus gets sugar Legumes and nitrogen fixing bacteria mutualism resources - -- Plants get nitrogen - Bacteria gets sugars Termites and protozoans in their gut mutualism resources - -- Protozoans get a safe place to live and constant supply of wood to break down - Termites get the products of that nutrition (Ligin and cellulose) Alpheid shrimp and pinkbar goby mutualism resources - -- Shrimp gets warning if predators are approaching (blind) - Goby gets a borrow to hide in Cleaner wrasser and large fish defense mutualism - -- Cleaner wrasser gets food - Large fish get parasites removed oxpecker and mammals defense mutualism - -- Oxpecker gets food (ticks) - Mammals get tick removal Bats and bat pollinated plants - -- Plants have evolved to open at night - Bats get nectar - Plants gets pollen dispersal ANts and some plants seed dispersal mutualism - -- Ants eat parts of seed to get protein rich elasomer - Plants get seed dispersal from ants not consuming whole seed and throwing it away Specialist mutualisms could become mre vulnerable to becoming endangered if their mutualists partner is in trouble - -- Clark nut cracker only eats seeds from white-bark pine - Whitepark is in decline because of white pine blister rust and mountain pine beetle - If Whitebark pine goes extinct so does clarks nut cracker