1 a Define ecology UNIT IV STUDY GUIDE Ecology BSC 2011 Ecology the study of the interactions between organisms and their environment The branch of biology that developed from natural history b How does a population differ from a community Population a group of organisms of same species co occurring in time and space Community all the organisms inhabiting a specific geographical area For example in a tide pool the community would be the seastars crabs barnacles algae etc ALL SPECIES The difference being that the population consists of just a signal species and the community consists of a group of species and their interactions In my own words A community is a bunch of different animals interacting together a population is one species interacting together c How does a community differ from an ecosystem Ecosystem A system that includes all living organisms biotic factors in an area as well as its physical environment abiotic factors functioning together as a unit Abiotic components nonliving chemical and physical factors Temperature moisture light soil These features are studied because they are an important part of the organism s life They often determine which species survive in a particular environment Ex A complete study of the ecology of moles would include an examination of the types of soil in which they dig their tunnels Biotic components living components all the organisms in a particular environment Animals trees bacteria predators mates pathogens Living organisms affect other living organisms All organisms depend on others directly or indirectly for food shelter repro d or protection Ex Goldfish in a bowl Does the goldfish live alone or with other fishes Are there live plants in the bowl How do the fish get food The goldfish needs members of the same species to reproduce To meet its needs the goldfish may complete with organisms of the same or different species that share the bowl d Please provide a specific example that exists in nature of a population a community an ecosystem Population This is a population of Equus zebra aka Zebras in habitants of the African grasslands Community This community of flowers is made up of different species of flowers in the same garden Ecosystem The coral reef ecosystem is a diverse collection of species that interact with each other and the physical environment 2 a Define demography and list several types of vital statistics used in demography Demography the study of pop n vital statistics and the factors that influence these Vital Statistics Population S ize absolute of individuals Population D ensity Population D ispersion individuals area or volume how individuals are distributed in a population b Be able to interpret age structure diagrams for populations One of the tools that demographers use to understand population is the age structure diagram This diagram shows the distribution by ages of females and males within a certain population in graphic form 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 Age structure diagrams show how a population is distributed It divides the population into pre reproductive reproductive and post reproductive phases The shape of the diagram can show you if a country is growing rapidly slowly or negatively It can also show is there is zero growth The wider the base of the diagram the more individuals below the age of fifteen The more individuals under fifteen the more individuals poised to reproduce increases The left hand side is always the males 3 a What is a cohort What can a person learn from a life table and a reproductive table that has been constructed for a particular population of some species I don t why this is crossed out but I ll answer the basics of it Cohort a group of individuals born at the same time Life Table an age specific summary of survival for a population b Be able to interpret survivorship curves Survivorship Curve a demographic tool survival as a function of age a graph showing the or proportion of individuals surviving at each age for a given species or group Type I low death rate when young higher late in age large investment of E caring for relatively few young most survive to max lifespan humans and other large mammals Type II intermediate type curve and intermediate E investments relatively constant death rate regardless of age at any age i e cause of death unrelated to age birds small mammals some lizards Type III high death rate when young but then declines for the relatively few survivors little or no investment of E caring for large s of offspring few survive to max lifespan trees marine inverts fish c Explain the concept of trade offs with respect to life history Life History of an organism is a species specific pattern of birth reproduction and death Trade offs between energy needed for survival and reproduction shape a species life history over evolutionary time 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 Life History of an organism is a species specific pattern of birth reproduction and death Life History Traits Age of first reproduction Frequency of reproduction Length of reproductive activity of offspring per brood or episode Grow slow Live long Reproduce once and die many offspring Grow quickly Live not so long Reproduce once many offspring Variable growth lifespan Multiple bouts of reproduction fewer offspring bout Coconut Palm Cocos nucifera 2 General Life History reproductive patterns Semelparity big bang reproduction Reproduce once and die Usually many offspring with low chance of survival Salmon century plants many annuals dandelions response to a variable environment adaptive often an Iteroparity repeated reproduction throughout life usually fewer offspring brood but higher survival e g most mammals HUMANS to more stable environments adaptation an 4 a Explain what carrying capacity is Carrying Capacity K Max number of organisms that a specific environment can support b How does carrying capacity affect population growth The environment can support this many organisms If population size rises above the carrying capacity more organisms die than are born The population drops below the carrying capacity 5 a Explain the difference between a population that grows exponentially as opposed to
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