Hierarchical Life History AxesTraining of maturityFrequency of ReproductionEffort per Reproductive BoutDistribution of EffortAcross all lifeAcross major phylogenetic scalesAcross major linages (mammals, molluscs, angionsperms)Across genera (sunflowers)Within single speciesEnviornmentr speciesdN/dt = B-D B = bN , D= dNdN/dt = rNDensity Dependent (Logistics Growth Models)dN/dt = rN [(K-N) / K] Hierarchical Life History Axes- Training of maturity- Frequency of Reproduction- Effort per Reproductive Bout- Distribution of EffortLife History Variation- Across all life- Across major phylogenetic scales- Across major linages (mammals, molluscs, angionsperms)- Across genera (sunflowers)- Within single species- Enviornmentr species- Produce many offspring- Reproduce early in life- Small body size- Rapid development- Grow from low population to high very quickly- Boom/bust cycle (opportunistic)- Unpredictable environment- Develop fastk Species- Produce few offspring- Reproduce later in life- Competitive- Large body size- Develop slowly- Constant population- Constant environmentDo life history strategies evolve?- With trade-offs- Natural selectionSemelparous- r species - Only reproduce once- Die after reproductionIteroparous- Reproduces more than once- Put energy into survival and growthDarwinian Demon- Harvests large amounts of energy- Lives forever- Always reproduces- No such organism- Offspring always big and surviveOntogenies of resource allocation- Description of development- How much energy is being put into growthCensus- Actual count of all organismsPopulation density- Number of individuals per unit areaPopulation growth rate- Change of number of individuals at a given timeDistribution- Size, shape, and location of the area it occupies and the spacing of the individuals in the areaAbundance- Total number of individuals, biomassDensity- Number of individuals per unit areaMalthus’ Equation- There is a limit to how many people earth can support- Food supply can’t keep up with growth- Limit population growthDiscrete Time Model (Geometric Growth)- Not continuous- λ = Nt+1 / Nt- Count individuals at two times- is the slopeΛ- What population will be after t generations, in closed systemContinuous Time Models (Exponential Growth Model)dN/dt = B-D B = bN , D= dNdN/dt = rN- Continuous births and deaths- Assume resources unlimited, random mating, no immigration- Predict what population will be after t- Size after t generations, continuous growthDensity Dependent (Logistics Growth Models)dN/dt = rN [(K-N) / K]- N<K, r +- N=K, r=0- N>K, r-- Population will initially increase- K is constanto Is likely to change over both space and timeo All individuals equalo Each 1/KthContinuous vs. Discrete- Continuous any number (distance)- Discrete limited whole number (Number of
View Full Document
Unlocking...