BSC 2011 UNIT IV STUDY GUIDE Ecology 1 a Define ecology Ecology is the study between organisms and their environment b How does a population differ from a community A population is a group of organisms of the same species living in a particular area while a community includes all the organisms living in that area c How does a community differ from an ecosystem While a community is all the organisms in a particular area an ecosystem includes the abiotic and biotic factors of the environment living and nonliving things in environment d Please provide a specific example that exists in nature of a population a community and ecosystem In a specific environment a population is a herd of deer a community is the deer trees insects bacteria mushrooms wolves and flowers the ecosystem is the deer trees insects bacteria mushrooms wolves flowers sum lake soil rocks rain snow and heat 2 Define demography and list several types of vital statistics used in demography Demography is the study of population vital statistics and the factors that influence these Vital statistics include population size population density and population dispersion b Be able to interpret age structure diagrams for populations c Discuss the appearance of an age structure diagram for a population that is growing rapidly as opposed to one that is actually decreasing in size or experiencing ZPG zero population growth In rapid growth majorities are of childbearing age which indicates that there is rapid population growth broad base In no growth or zero population growth most are past childbearing age narrow base 3 b Be able to interpret survivorship curves Type I Survivorship Curve humans and other mammals low death rate when young higher late in age large investment of E caring for few young most survive to max lifespan Type II Survivorship Curve trees marine inverts fish high death rate when young little to no E investment in offspring few survive max lifespan Type III birds small mammals intermediate curve and E investments constant death rate regardless of age cause of death unrelated to age c Explain the concept of trade offs with respect to life history A trade off exists between energy spent on survival vs reproduction The life history strategy of energy tradeoffs of a species evolves over time to maximize fitness There is a cost of parental care on a parents survival Different strategies for the tradeoff between energy for reproduction and energy needed for survival to maximize fitness A sparrow has less energy invested in survival and more into reproduction so they reproduce earlier and at a higher rate An albatross has more energy in survival than reproduction so he lives longer and by living longer he can produce enough offspring to maintain the species d Explain what a species life history refers to and provide an example of two species that have different or contrasting life history strategies describing how they differ A species life history is the strategy of energy tradeoffs of a species that evolves over time to maximize fitness Two life history patterns are semelparity and heroparity Semelparity species reproduce once and then die having many offspring with a low chance of survival like a salmon or century plant Heroparity species repeat reproduction throughout life with fewer offspring but higher survival most mammals Semelparity has an adaptive response to a variable environment and heroparity has an adaptation to more stable environments 4 a Explain what carrying capacity is Carrying capacity K is the maximum population size a particular environment can support b How does carrying capacity affect population growth The size of a population can only grow to equal the amount of resources the environment can provide carrying capacity So if there aren t many resources in an area and too large of a population then there will be starvation and a fight for resources But if there is an overabundance of resources and the carrying capacity is very high then the population will grow 5 a Explain the difference between a population that grows exponentially as opposed to one that grows logistically With exponential growth population growth continues as if there is no K or carrying capacity of an environment With logistic growth population growth slows as population reaches K the carrying capacity of an environment b Describe the shapes of the two different growth curves Exponential growth is J shaped and logistic growth is S shaped c What does the logistic equation take into account that the exponential equation does not Logistic growth takes into count the logistic growth equation the fraction of K the maximum population size a particular environment can support still available as N the population increases d Define the meaning of each term in the logistic growth equation K is the maximum population size a particular environment can support N is the population size e What is the difference between r and rmax r is the per capita rate of population increase or an average individuals contribution to increasing population size Rmax is a species specific intrinsic rate of increase and reflects the maximum per capita rate of increase under ideal conditions 6 Imagine a natural population say a newly established small population of mice in large meadow that is initially small in size and that will proceed to grow logistically Describe how the rate at which this population grows changes over time as it continues to grow in a natural environment in which there are limited resources The mice population will grow rapidly until it reaches the carrying capacity of the environment and then stops growing 8 a How does a Type I survivorship curve differ from a Type III curve with respect to both age specific mortality and survivorship lifespan Type I survivorship curve have a low death rate when young and most survive to the max lifespan Type III curve has a high death rate when young and only few survive to maximum lifespan b Name two types of organisms exhibiting Type I survivorship and two others that exhibit Type III survivorship Type I includes humans and large mammals and type III includes trees marine inverts and fish 9 What is the concept of maximum sustainable yield and how might you best manage a population for maximum sustainable yield The maximum number of individuals that can be harvested right now that will allow the population to return to its carrying capacity as quickly as possibly making it ready for another
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