Ecology Exam 1 Study Questions and Accurate Answers (100% Correct).

Ecology Exam 1 Study Questions and Accurate Answers (100% Correct). ecology an understanding of the relationships between organisms and their environment or the study of interactions that determines the abundance and distribution of a species what causes dead zones? pesticide and fertilizer run off along the Mississippi River which streams into the Gulf of Mexico....leads to dead zones (too much phosporous and nitrogen--causes algae to grow and die suddenly, during decomposition, oxygen is depleted which results in the death of animal life) environment the external physical and biological factors influencing growth, survivorship, development and reproduction of organisms abiotic factors physical environment including climate, soil, nutrients, fire, floods etc. biotic factors biological environment including competitors, predators, prey, diseases, etc. habitat a place where organisms live and the environmental factors found there what is the first general principle of ecology? ecological systems function according to the laws of thermodynamics what is the second general principle of ecology? the physical environment exerts a controlling influence on the productivity of ecological systems what is the third general principle of ecology? the structure and dynamics of ecological communities are regulated by population processes what is the fourth general principle of ecology? over generations, organisms respond to change in the environment through evolution with populations first law of thermodynamics? energy can niether be created nor destroyed, only changed second law of thermodynamics? in each energetic transformation, potential energy is reduced, as some energy is lost to the system as heat (entropy increases in a closed system) the second law of thermodynamics states that energetic transdormations are always less than _______ efficient 100% What kind of system is an ecosystem? open, because the sun is a constant source of energy What would happen to an ecosystem without a constant source of energy? the ecosystem would degrade the second law places a limit to the number of ______ in an ecosystem trophic levels population a group of interbreeding individuals of the same species found in the same place (sympatric) at the same time species a group of actually or potentially interbreeding individuals that are reproductively isolated from all other kinds of organisms community the assemblage of plants, animals, microbes or other organisms living int the same habitat and that interact and affect one another ecosystem an environmental unit consisting of biotic and abiotic components related through exchanges of energy and nutrients metapopulation assemblages of populations of individuals of a particular species within a large spacial scale with the long term survival of the species depending on a shifting balance between local population extinctions and recolonizations in the patchwork of a fragmented landscape producers autotrophs that can either photosynthsize or chemosynthesize (primary production based on photosynthesis) consumers organisms that consume other living organisms decomposers organisms that consume non living organic material herbivores animals that feed directly on producers approximately how much energy is transferred from one trophic level to the next? 10% what are four reasons that energy is lost from one trophic level to the next? not all organisms are consumed, not all parts of organisms are consumed, not all energy consumed is assimilated, most energy assimilated is lost to respiration evolution a change in the genetic frequency of a trait in a population at what level does evolution occur? population at what level does natural selection occur? individual what does theory mean as applied to evolution? a statement of general laws, principles, or causes of something known or observed what are the four Darwinian postulates of evolution? variation exists between populations for any given trait, the genetic traits of organisms are inherited from their parents, more individuals are produced than can survive, the process of natural selection preserves the most fit cultural/ artificial selection used to produce the disparate breeds of animals and plants that have been produced by mankind in remarkably short periods of time parallel evolution evolution of similar adaptations among groups that have a common origin, but which were geographically separated at an early stage in their history convergent evolution evolutionary lines far removed from each other, evolve similar traits in response to similar environmental conditions (sometimes using different starting materials) biological species concept according to this definition, we assume that species are separated by a reproductive isolating mechanism distinct cluster of genes a species is a population sharing enough similar genes is considered to be the same species allopatric model of speciation species is divided into two populations, no gene flow, each population is genetically distinct, each population finds a unique environment in which natural selection follows a different course, population diverges from original gene pool, if two populations are brought back into contact they cannot produce viable offspring ecotype a genetically distinct population within the same species, differences not significant enough to be subspecies subspecies when geographical isolation is incomplete and the differences among the populations are significant enough; dog is a subspecies of the wolf, can interbreed and produce viable offspring adaptation a genetically determined characteristic that enhances the ability of an individual to cope with its environment acclimation a phenotypic response to the environment, often a reversible change in the morphology or physiology of an organism in response to an environmental change evolution a change in the genetic frequency of a trait in a population or species over time at what level does evolution occur? population level at what level does natural selection occur? at the individual level definition of theory as it applies to evolution a set of general laws, principles or causes of something known or observed what are the four Darwinian postualtes of evolution? variation exists within and between populations, the genetic traits of organisms are inherited from their parents, more individuals are produced than can survive, the process of natural selection preserves the most fit cultural/artificial selection used to produce disparate breeds of plants and animals that have been produced by mankind in remarkably short periods of time parallel evolution evolution of similar adaptations among groups that have a common origin but were geographically separated at an early stage in history convergent evolution evolutionary lines far removed from each other evolve similar traits in response to similar environmental conditions (same adaptations but using different starting materials) biological species concept assumes that species are separated by a reproductive isolating mechanism distinct cluster of genes concept a population sharing enough similar genes is considered to be the same species allopatric model of speciation species divided into two populations, no gene flow, each population is genetically distinct, each population has unique environment in which natural selection follows a different course, population diverges genetically from original gene pool, long isolation period, if reunited wont produce viable offspring subspecies geographical isolation is incomplete and differences in populations are significant enough to be called subspecies; dog is subspecies of wolf, the two can interbreed ecotype a genetically differentiated population within a species with differences having ecological significance adaptation a genetic response to the environment changing acclimation a phenotypic response to the environment, often a reversible change in the morphology or physiology of an organism in response to environmental change first principle of population ecology populations tend to grow exponentially assuming that the growth parameter is not zero how do you make a growth curve linear? if you take the natural log of population size deterministic model conditions are specified leading to an exact outcome based on the parameters assigned stochastic model population parameters vary according to some kind of frequency distribution; distribution has a central tendency but has a range of variability around the mean second principle of population ecology principle of self limitation in which there is an upper bound beyond which a population cannot increase anymore carrying capacity the population size at which growth rate is equal to zero, the maximum amount to organisms that an environment can sustain third principle of population ecology consumer-resource interactions tend to produce oscillations discrete population growth populations with distinct generations, no overlap between adults and offspring continuous growth population populations having continuous growth and overlapping generations without age distribution effects