Quiz 3 Study Guide
Quiz 3 Study Guide Bios 207
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This 3 page Study Guide was uploaded by Cara Cahalan on Thursday April 7, 2016. The Study Guide belongs to Bios 207 at University of Nebraska Lincoln taught by in Spring 2016. Since its upload, it has received 8 views. For similar materials see Ecology and Evolution in Biology at University of Nebraska Lincoln.
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Date Created: 04/07/16
Quiz 3 Study Guide 1 2/12: Life History Tradeoffs (1) Class: Life history history of events during a life that are related to births and deaths Life history traits events themselves or the rates that quantify the transition Trade off doesn’t tell you the best decision, just what the possible choices are. (beer example) Relationship between mean egg size and clutch size across sites is: negative Life history tradeoffs arise from constraint o Energy spent= storage + growth + maintenance + reproduction o E= S + G + M + R o R= N x C (N number of offspring, C cost per offspringsize) o Qualityquantity tradeoff More seeds smaller mass. Less seedsbigger mass (quantityquality tradeoff) o R=N x C= 100,000 x 0.1 = 10,000 E= S + G + M + R o No storage (S=0) and nongrowing adult (G=0) o E= M + R (hard to measure energy or resource allocations) Readings: Classifying reproductive diversity: o Number of offspring Semlparous reproduces once in a lifetime (annual plants) Iteroparous reproduces multiple times o R/k selection spectrum of population growth rate from fast to slow rselection (rintrinsic rate of increase), selection for high population growth rates Kselection (Kcarrying capacity) selection for slower rates of increase o Plant survival depends on stress (external abiotic factor) and disturbance (destruction of biomass) Competitive (low stresslow disturbance) plants that can acquire more resources are better Ruderals (low stress high disturbance) weedy, adapt to brief periods of intense exploitation Stresstolerant (high stresslow disturbance) slow growth rates, slow rates of water and nutrient use o Taking out effects of variables allows for the study of life histories of different organisms 2/15: Life History Tradeoffs (2) Class: What tradeoff is illustrated with these data? o Reproductionsurvival trade off (more offspring fewer survive, fewer offspring more survive) What tradeoff is illustrated in the second? o Reproductionsurvival tradeoff (bigger thorax length longer life) o Positive relationship is not a tradeoff Slope of tradeoff curve is ALWAYS NEGATIVE Growth ratereproduction tradeoff (More cones per tree smaller ring index) o More energy going into producing cones instead of growing itself Quiz 3 Study Guide 2 Opossums: both graphs has positive slopes o What do opossums trade for their longer lives? Slower aging (indicating survivorship) Stronger muscle fibers (gives them slower aging) Reproduction o Reproductionsurvival tradeoff: Island longer life span fewer litters Mainland shorter life span more litters o C longer it takes for muscle fiber deterioration more connections more aging Takes place faster on mainland than island Quantityquality trade off shown in figure A and B o A (quantity) high predation more offspring, low predation fewer offspring o B (quality) high predation smaller embryos, low predation larger embryos They are putting less energy into growth under high predation risk (look at C). Where are they putting the energy instead? o Reproduction o Remember: E= S + G + M + R (cannot be separated from each other within a single organism) The Ecological Theater and Evolutionary Play (by: G. Evelyn Hutchinson, 1965) o Metaphor between ecology and evolution Essential features of life history tradeoffs o Negative correlation between traits (paying a price) o Constrain on energy, space, time, money o Tradeoff doesn’t tell you the right strategy o E= S + G + M + R (budget) o Competing positive ends (traits compete because they are both positive, not one + and one ) o Quantitative trait with variation across environment Readings: 12.1 Selection across a Lifetime Lifetime fitness of an organism is determined in part by the tradeoffs it experiences between competing demands Opossum example: different life history strategies o Mainland opossums created more offspring in the first year because of the predation threat present on the island o Island opossums didn’t have as many offspring at first, but were able to survive long enough to have a second liter Tradeoffs arise when allocation of resources to one lifehistory trait reduces investment in another trait Investment in reproduction comes at the expense of growth or body maintenance Selection may favor mutations that are beneficial early in life, even if those same mutations are harmful later on. Investment in reproduction early in life often reduces an individual’s ability to breed in life Change in selective environment can bring about rapid evolution of lifehistory traits 12.2 Parental Investment Operational sex ratio doesn’t necessary always point to males being in higher supply, is dependent on reproduction and other characteristics of the organism o Seahorses females transfer eggs to males who rear them. OSR favors more available females 2/17: Life History Adjustments Quiz 3 Study Guide 3 Class: Clownfish social experience changes organism anatomy and physiology o Biggest clownfish are female, when they die next largest male becomes female o Each fish is successively smaller than the next to avoid conflicts o Larger anemone support more fish larger hierarchy of rank o Size number trade off Male sand gobies adjustment of family size: Readings: Sequential hermaphroditism changes in sex over the course of a life cycle Way to cope with uncertainty of reproduction is to use flexible strategy to respond to different challenges Females can manipulate the OSR to their needs (either producing more sons or daughters) Females generally benefit more than males from parental care off offspring Reversals in OSR, when they occur, can also cause a reversal in the more typical roles of the sexes (testing sexual selection theory) 2/19: Population Growth Class: t Geometric population growth occurs in discrete time periods: tN λ 0 o Parents are no longer with parents (annuals) 1 N T t o Solve = ( N = lambda 0 rt Exponential growth occurs continuously: N tN e0 o Humans, most organisms λ=e r Therefore… For population growing exponentially what is constant through time? o Number of males and females o Growth rate o Number of individuals Population decline r<0 Population is stable r=0 Population growth r>0 Growth rate, r=birth rate – death rate o Birth rate resources, fecundity, offspring survival, female choice, age at first breeding o Death rate longevity, predators, parasites, pesticides, malemale competition, resources Readings:
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