Ecology is the scientific study of the interactions between organisms and their environment. Concept 50.1 Ecology is the study of interactions between organisms and the environment Ecology and evolutionary biology are closely related sciences. * Ecology has a long history as a descriptive science.
* Modern ecology is also a rigorous experimental science. * Ecology and evolutionary biology are closely related sciences. * Events that occur over ecological time (minutes to years) translate into effects over evolutionary time (decades to millennia). * For example, hawks feeding on field mice kill certain individuals (over ecological time), reducing population size (an ecological effect), altering the gene pool (an evolutionary effect), and selecting for mice with fur color that camouflages them in their environment (over evolutionary time). Ecological research ranges from the adaptations of individual organisms to the dynamics of the biosphere. * The environment of any organism includes the following components: * Abiotic components: nonliving chemical and physical factors such as temperature, light, water, and nutrients. * Biotic components: all living organisms in the individual’s environment. * Ecology can be divided into a number of areas of study. * Organismal ecology is concerned with the behavioral, physiological, and morphological ways individuals interact with the environment. * A population is a group of individuals of the same species living in a particular geographic area. Population ecology examines factors that affect population size and composition. * A community consists of all the organisms of all the species that inhabit a particular area. Community ecology examines the interactions between species and considers how factors such as predation, competition, disease, and disturbance affect community structure and organization. * An ecosystem consists of all the abiotic factors in addition to the entire community of species that exist in a certain area. Ecosystem ecology studies energy flow and cycling of chemicals among the various abiotic and biotic components. * A landscape or seascape consists of several different ecosystems linked by exchanges of energy, materials, and organisms. Landscape ecology deals with arrays of ecosystems and their arrangement in a geographic region. * The biosphere is the global ecosystem, the sum of all of the planet’s ecosystems.
Ecology provides a scientific context for evaluating environmental issues. * In 1962, Rachel Carson’s book Silent Spring warned that the use of pesticides such as DDT was causing population declines in many nontarget organisms. * Today, acid precipitation, land misuse, toxic wastes, habitat destruction, and the growing list of endangered or extinct species are just a few of the problems that threaten the Earth. * Our ecological information is always incomplete. The precautionary principle (essentially “an ounce of prevention is worth a pound of cure”) can guide decision making on environmental issues. Concept 50.2 Interactions between organisms and the environment limit the distribution of species * Biogeography is the study of past and present distributions of individual species in the context of evolutionary theory. Species dispersal/transplant contributes to the distribution of organisms * The movement of individuals away from centers of high population density or from their area of origin is called dispersal. * The dispersal of organisms is crucial to understanding geographic isolation in evolution and the broad patterns of geographic distribution of species. * One way to determine if dispersal is a key factor limiting distribution is to observe the results when humans have accidentally or intentionally transplanted a species to areas where it was previously absent. * For the transplant to be considered successful, the organisms must...
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