BSC2011 Final Exam Vocabulary List Ecology the scientific study of the interactions betweens organisms and the environ ment Ecological interactions occur at a hierarchy of scales that ecologists study from single organisms to the globe Climate the long term prevailing weather conditions in a given area It is the most sig nificant influence on the distribution of organisms on land and in the ocean Biosphere is the global ecosystem the sum of all the planet s ecosystems and land scapes Global Ecology examines how the regional exchange of energy and materials influ ences the functioning and distribution of organisms across the biosphere Landscape or seascape is a mosaic of connected ecosystems Landscape Ecology focuses on the factors controlling exchanges of energy materi als and organisms across multiple ecosystems Ecosystem is the community of organisms in an area and the physical factors with which those organisms interact Ecosystem Ecology emphasizes energy flow and chemical cycling between organ isms and the environment Community is a group of populations of different species in an area Community Ecology examines how interactions between species such as predation and competition affect community structure and organization Population is a group of individuals of the same species living in an area Population Ecology analyzes factors that affect population size and how and why it changes through time Organismal Ecology which includes the sub disciplines of physiological evolutionary and behavioral ecology is concerned with how an organism s structure physiology and behavior meet the challenges posed by its environment Abiotic nonliving factors the chemical and physical attributes such as temperature light water and nutrients that influence the distribution and abundance of organisms Biotic living factors the other organisms that are part of an individual s environment similarly influence the distribution and abundance of life on Earth Biomes major life zones characterized by vegetation type in terrestrial biomes or by the physical environment in aquatic biomes Disturbance is an event such as a storm fire or human activity that changes a com munity removing organisms from it and altering resource availability Oligotrophic Lakes are nutrient poor and generally oxygen rich Eutrophic Lakes are nutrient rich and often depleted of oxygen in the deepest zone in summer and if covered with ice in winter Dispersal the movement of individuals or gametes away from their area of origin or from centers of high population density To observe if dispersal is a key factor limiting the distribution of a species ecologists may observe the results of intentional or acci dental transplants of the species to area where it was previously absent Immigration the influx of new individuals from other area Emigration the movement of individuals out of a population and into other locations Demography is the study of the vital statistics of populations and how they change over time Life Tables age specific summaries of the survival pattern of a population Survivorship Curve a plot of the proportion or numbers in a cohort still alive at each age Type 1 2 3 curves that are for large mammals like humans birds and fish marine invertebrates respectively Cohort a group of individuals of the same age from birth until all of the individuals are dead Exponential Population Growth also known as geometric population growth This condition is when a population whose members all have access to abundant food and are free to reproduce at physiological capacity dN dt rmaxN Zero Population Growth ZPG occurs when the per capita birth and death rates are equal so r 0 r the per capita rate of increase Carrying Capacity K is the maximum population size that a particular environment can sustain Logistic Population Growth the per capita rate of increase approaches zero as the carrying capacity is reached dN dt rmaxN K N K Life History the traits that affect an organism s schedule of reproduction and survival It entails three main variables when production begins the age at first reproduction or age at maturity how often the organisms reproduces and how many offspring are pro duced per reproductive episode Semelparity reproduces only once in its life time this is typically some plants This type of reproduction would work better in environments under less dependable condi tions Iteroparity repeated reproduction This type of reproduction may be favored in more dependable environment Trade off between reproduction and survival No organism could produce as many off spring as a semelparous species and provision them as well as an iteroparous species K Selection is density dependent selection Selection for traits that are sensitive to population density and are favored at high densities r Selection is density independent selection selection for traits that maximize repro ductive success in uncrowded environments low densities Occurs in environments that are well below the carrying capacity Density Independent a birth rate or death rate that does not change with population density Density Dependent a death rate that rises as population density rises Mechanisms of density dependent regulation competition for resources predation toxic wastes in trinsic factors territoriality and disease Population Dynamics population fluctuations from year to year or place to place For example fluctuations in fish populations influence seasonal harvests of commercially important species Metapopulation when a number of local populations are linked Demographic Transition the movement from high birth and death rates toward low birth and death rates which tends to accompany industrialization and improved living conditions Age Structure the relative number of individuals of each age in the population Ecological Footprint summaries the aggregate land and water are required by each person city or nation to produce all the resources it consumes and to absorb all the waste it generates It is measured in units of land per person Interspecific Interaction include competition herbivory symbiosis and facilitation These are all interactions with individuals of other species in the community Interspecific Competition a interaction that occurs when individuals of different species compete for a resource that limits their growth and survival Competitive Exclusion local elimination of the inferior competitor Ecological Niche the sum of a species use of the biotic and abiotic
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